Commercial Pilots who don't know about piston engines

[Lumps]

If you are one, please, at the minimum read John Deakins old Pelican Perch articles on AvWeb, or any of Jabawocky's posts concerning engine management right here on the prunes.

If you are thinking of sticking around in GA and potentially abusing many engines over many hours I strongly recommend the Advanced Pilot course. You will be on the right side of history.

If this does not pique your interest, make you question your shiny-shoed instructors advice and make you want to dig deeper on the subject...

If you rely on old wives tales to set your mixture, think that fuel cools an engine from evaporation, pull a Continental engine back to 25" after take off.... in short, if you cannot think for yourself and are not at all curious GO AND FLY TURBINES.

They are marvellous things that by now have engineered out the requirement for any sort of deep knowledge and understanding of what's going on under the cowl.

Piston engines are also marvellous creations, even more marvellous in the eyes of some because, in the higher powered examples, you have to THINK. You can break stuff (eventually) if you don't THINK. There are expensive consequences for not knowing stuff. Some derive some sort of satisfaction at a job well done in this regard. Others think that a CHT of 460°C is fine because the absolute limit is 500°C :sad:

Never thought I'd rant on pprune but there it is. Just had our pristine, factory new, pampered, GAMI'd, EDM'd 540 defiled by yet another victim of our collective ignorance.

Also never thought I'd use emoticons

Peace

"Pelican's Perch" Index - AVweb Features Article (http://www.avweb.com/news/pelican/182146-1.html)

Advanced Pilot (http://www.advancedpilot.com)

Yes, I am a follower of the Holy Trinity: George, John & Walter. They are shining light where there was darkness....

[wishiwasupthere]

That's all good and well, but at the end of the day, when you're being paid to fly someone else's machines, you fly them how they want you to fly them (caveat that with 'as long as it's safe). You can't just go and fly them how you want to because you read something on the Internet.

[Car RAMROD]

You can also degrade a turbine engine by running it just below the absolute limit or by crap handling practices too.

What's your point?


So who broke your fancy new engine? Did you hire it out to an idiot or did one of the pilots in your employ not get taught by you "correctly"? Were they following the AFM or the magical teachings on the internet?

[updown]

It's probably not fair to put all the blame on the pilot...

Did the operator provide adequate training? Did the owner (you) do research before leasing out the aircraft to the operator? Does the operator have a history of ****ing engines? How does he instruct his line pilots to lean the engines? Have you asked them this? :rolleyes:

I remember my GA days. The owner of the company insisted we run the EGT right before it would cut out to save $$$$ on fuel. Not his engines so he didn't care. Not that all the pilots did that....

[BubbaMc]

How was your engine defiled in this case?

[Lumps]

It was flown by an employee of the manufacturer. My bad for assuming they would know what they're doing. Clearly, they wrote the AFM. In this specific case he got a number wrong from what he was actually told, and was leaning (300hp) engine to as low as 76lph at full power.

No damage done, but looking at the EDM data you can see the confusion as mixture goes down, then back up as CHTs shoot through 400°F, then down again... and so on.

Yes, the online APS course is magical.

[Lead Balloon]

That's all good and well, but at the end of the day, when you're being paid to fly someone else's machines, you fly them how they want you to fly them (caveat that with 'as long as it's safe).You don't know it's 'safe' unless you know how a piston engine actually functions and what the various controls actually do to its innards.

The blissfully ignorant are generally only 'safe' because most GA piston engines are engineered to take a lot of abuse. Those who run GA piston engines on the basis of data and knowledge are 'safer', because they aren't exposing the engine to unnecessary abuse.

But Lumps: You were a little naive in believing that an employee from a manufacturer would know what he was doing, given some of the demonstrable rubbish published by manufacturers.

[Jabawocky]

No doubt you have caught my attention.

LUMPS, are you the young fella who contacted me recently about LAME's and company folk not interested in fixing fuel flow on take off for a TC engine and with what by simple diagnosis of the EMS we think had advanced timing?

Or are you the guy who is an ex student from the Perth class? This sounds too much like their story but it is not hard to believe it is another example.

My personal opinion about owners and telling you how to do things, if you are suitably educated in the science of combustion, you should be able to convince the owner/operator that the practises need to change. And if they are really dangerous leave.

I think it is like a CP telling pilots to dive through holes on an RNAV…..(think Lockhart River type crash, not that the CP said it), just because they said to do it I doubt you would. Engine operation is similar.

Lead Ballon :ok:

Lumps……maybe you should suggest they book in for the Feb class in two weeks, only 3 spots left.

[Lumps]

But Lumps: You were a little naive in believing that an employee from a manufacturer would know what he was doing, given some of the demonstrable rubbish published by manufacturers.

Sadly, yes.

If read carefully tried to avoid blaming the pilot another victim of our collective ignorance. It'd be unfair as it's more of a aviation community thing.

Yes, you can bugger up turbines too with dunderheaded tactics, I just don't think they are as vulnerable to ignorance. Push the levers until the correct numbers are obtained. With pistons quite often know one knows what the correct numbers are, not helped by wrong figures in the AFM.

For example take the P&W R985 with a CHT limit of 550°F. If it was an ITT max continuous limitation in a turbine, you could assume running it at say 5-10% below the max continuous ITT would be prudent practise, typically nothing required more than routine maintenance. Run the R985 at 500°F all day and, well, you probably won't be flying all day after a while.

[FoolCoarsePitch]

You can also degrade a turbine engine by running it just below the absolute limit or by crap handling practices too.

What's your point?

I think his point is that with a turbine engine its all black and white in the sense that there is a power lever and needle. All the monkey needs to be taught is don't put the needle beyond that place. There is less room for dummies like in the OPs case to have heard something, run with it treating it as gospel and subsequently giving the engine undesirable treatment. I'm not saying it can't happen, but the scope for it to happen is MUCH less.

The owner of the company insisted we run the EGT right before it would cut out to save $$$$ on fuel.

The irony of this is that, at least at typical cruise settings, the engine would have been happier there than where you would have probably leaned it to.

Continental engine back to 25" after take off
https://i.imgflip.com/y9rmz.jpg

[iPahlot]

Now Lumps, Jaba et al, I'm not having a go at either of you and the engine operating methodologies you support. HOWEVER as mentioned in this thread, students should never just take stuff that is spoonfed to them by their instructors as gospel and do proper research, the same really can be said for LOP operation.

I'm sure you guys will agree that proper LOP needs proper engine monitoring, and properly balanced fuel injectors, not just a single EGT probe you'll find in the vast majority of GA pistons.

Now if some young (or not so young) impressionable person would read your research and then start operating a stock standard engine with 1970's era instrumentation against the owners and/or POH LOP, what are the possible consequences of doing this? Would you consider it safe if someone were to try this?

Having operated radials and a decent percentage of piston types that make up the GA fleet the most "modern" engine feature I've seen in 98% of these were fuel totalisers / digital fuel flow gauges.

Now again, I am by no means discounting the science, should I ever be silly enough to buy my own piston single/twin I will most certainly also invest in hardware that will allow me to safely operate LOP. :ok:

In the meantime I shall go back to monkey mode and push the levers on my PT6's and make sure I don't make the needles go over the line. :E

[Lead Balloon]

Safe ROP operations needs proper instrumentation and engine set up, too.

That's the joke. Those who don't want to operate their engines at settings that dare not speak its name are usually blissfully ignorant of where the engine is set! :}

[iPahlot]

Safe ROP operations needs proper instrumentation and engine set up, too.

Touche :ok:

[FoolCoarsePitch]

Nobody has mentioned anything about LOP operations. Of course you need the proper equipment and knowledge to be able to do it safely and correctly. The grievance of this thread is to do with people routinely doing what you should definitely NOT do period. The follow-on from that topic is the disappointment that many of us share. The disappointment that many of our fellow aviators just do not seem to care or be in the slightest bit interested in the intricacies of the trade. Back in the day when I started reading Pelican Perch it got me hook line and sinker.

[Aerozepplin]

You don't need to be operating LOP or have all-points monitors to gain value from understanding your engine properly. I largely operate low powered carb engines, but have gained a great deal from the writing of Deakin etc.

When teaching a student about leaning I can tell them how it actually works rather than the usual "leaning too much destroys engines!" that I got when I was learning. Likewise why the engine runs rough when you lean aggressively, that it's the leanest cylinder falling off the HP curve, not the engine detonating (as many instructors I know believe).

With that said every time I fly my little O-235 I'm running LOP. If I lean till rough then enrich till smooth the leanest cylinder(s) are likely LOP, possible with some others at peak or ROP. Which is why I laugh when people say "You can't LOP without the equipment!". True I can't climb LOP etc, but how to do I know where each cylinder is on my horrible EGT spread? And unless I'm at high power settings it doesn't matter. Considering the POH tell me to operate it at the worst EGT it could it's not like things could get any worse is it?

[Lead Balloon]

According to wishiwasupthere, that's just stuff you read on the Internet, FoolC! :}

All discussions about piston engine operations are implicitly about ROP and LOP, because:

- if an engine's running, each piston is somewhere on that lean curve, and

- the only way - repeat, the ONLY WAY - to be sure that you are NOT doing something that you should "definitely NOT do" is to know where each cylinder is on that curve.

[Hasherucf]

From experience in maintaining several commercial operators fleets most aircraft still have the old egt/cht combo. Cessna old engine clusters are especially bad for for discerning any useful information. At best you can say 'your in the green' . The scale seems non linear and wishful at best. Full engine trend monitoring is rare as operators don't want to spend the coin.

[Eddie Dean]

Hasher, have the non precision instruments,that we know and love,been detrimental to engine longevity?
Hasn't seemed to have mattered in my limited experience.

[neville_nobody]

From memory the point of those articles were that owners should spend money on a proper all cylinders temperature measurement.

And the irony here is that if they did that flying a piston with that gear in it is really the same as flying turbines! Not hard to blow up or overtemp a turbine engine.

[tio540]

As a novice pilot, I am concerned this post starts buy suggesting engine management advice should be taken from an anonymous contributor called Jabawocky, some dentist, and a lawyer. The industry is in serious trouble.

[RatsoreA]

anonymous contributor called Jabawocky

Actually, he isn't anonymous, he has freely shared his real name and contact details in these forums on several occasions and has met in person many people on here, me included!

A basic search of the website will show you this...

[Aussie Bob]

As a novice pilot, I am concerned this post starts buy suggesting engine management advice should be taken from an anonymous contributor called Jabawocky, some dentist, and a lawyer. The industry is in serious trouble.

As a novice pilot you would do really well to meet Mr. Jabbawocky ....

[das Uber Soldat]

As a novice pilot you would do really well to meet Mr. Jabbawocky ....
Probably true, but its not his point.

[Ultralights]

just because someone is a dentist, lawyer etc, doesn not mean they do not know what they are talking about when it comes to engines, and engine management. yes, i have done the courses, and the Data doesnt lie.

[Lead Balloon]

All of the people who run the APS classes are publicly identified. You can shake their hands and ask them questions. And you can sue them.

Funny thing is that with all the dangerous folklore and wildly inaccurate misinformation they have been spreading over decades, they have yet to be sued for negligent misstatement. Not once. Extraordinarily lucky, considering how litigious the USA and Australia are supposed to be.

An alternative explanation is that their courses are based on science and data - science and data that saw vast improvements in piston engine efficiency and reliability over millions of hours of piston engine operations before the jet age. Very difficult to prove something said by APS is inaccurate, when the science and data prove otherwise.

You want to run an aero piston engine on the basis of a single EGT gauge and single CHT gauge? Go for it. The joke is that if you think the CHT gauge being 'in the green' and the EGT gauge being at some temperature relative to peak means that you're operating the engine as efficiently and as a safely as practicable, it's just blissful ignorance. The fact that the engine might survive the abuse or inefficient operation proves nothing, other than that many engines are manufactured with wide tolerances for abuse and inefficient operation.

A comparison between the condition and costs of running engines the blissful ignorance way, on the one hand, and the condition and costs of running engines on the basis of the science and data used by APS, on the other, is quite instructive. But only for those who are willing and able to learn.

(PS: I have no direct or indirect pecuniary interest in the APS courses. I have a direct interest in aviation safety.)

[iPahlot]

I don't think anyone is arguing the science. What I think people are arguing is that the notion of commercial pilots being ignorant for flying something with only an EGT...

I'd be very interested to see how many commercial companies are going down this route. I know of only one myself, but happy to be corrected.

it's all fine and good to spend money on your privately owned aircraft, but calculate the price it'd take to upgrade a dozen 200 series cessnas, Barons, Chieftains etc when most operators are already working to very tight margins given the increased costs of regulatory compliance, SIDS, ADSB, ageing aircraft etc.

In a perfect world operators would be buying new aircraft every 5 years. If this were the case the piston engine would probably be close to extinct because everyone would go for the safer and more economical option of operating turbines, but unfortunately this is far from a perfect world.

[Hasherucf]

Hasher, have the non precision instruments,that we know and love,been detrimental to engine longevity?
Hasn't seemed to have mattered in my limited experience.

No. Generally there is an outside problem that causes low compressions , burnt valves etc. Could be a newbie pilot , induction leak etc . Most engines go happily go through to overhaul.

[Jabawocky]

As a novice pilot, I am concerned this post starts buy suggesting engine management advice should be taken from an anonymous contributor called Jabawocky, some dentist, and a lawyer. The industry is in serious trouble.

That is So FUNNY ….. I love it! http://www.beechtalk.com/forums/images/smilies/rofl02.gif

The Lawyer……..:D:D:D :ok: Smartest guy I know and I know rocket scientists and Nasa Astronauts (No kidding either). And he just happens to be an Aeronautical engineer (check the engineering drawings on much of the Aerostar) and an FAA DER. and I could go on…..

Thanks for the compliments guys, but this thread was about abuse of an engine. I think the abuse has been stopped with intervention. :ok:

[Jabawocky]

iPhalot
Now Lumps, Jaba et al, I'm not having a go at either of you and the engine operating methodologies you support. HOWEVER as mentioned in this thread, students should never just take stuff that is spoonfed to them by their instructors as gospel and do proper research, the same really can be said for LOP operation.

I'm sure you guys will agree that proper LOP needs proper engine monitoring, and properly balanced fuel injectors, not just a single EGT probe you'll find in the vast majority of GA pistons.

Actually the truth is when you have a conforming engine, it is far easier and safer to run it LOP than ROP properly. Seriously proper ROP ops are harder to do. But you would need to understand why that is so to appreciate what I just said. Cheers :ok:

[hestonfysh]

What's wrong with 25/25?

[Lead Balloon]

As a novice pilot, I am concerned this post starts buy suggesting engine management advice should be taken from an anonymous contributor called Jabawocky, some dentist, and a lawyer. The industry is in serious trouble.You omitted to mention the other shyster in the APS team: John Deakin.

Mr Deakin only has about 37,000 hours in command, around half of it on 747s and the rest on Gulfstream IV, C-46, M-404, DC-3, F8F Bearcat, Constellation, B-29 and V35. What would he know?What's wrong with 25/25?Depends on the engine. But on many piston aero engines, reducing the revs to 2500 moves the peak pressure point closer to TDC (thus increasing the peak pressure) and reducing the throttle from e.g. Sea level MP to 25 effectively leans the mixture and increases the EGT and CHT.

The shysters at APS will have you believe that the 2 biggest enemies of cylinders are internal pressure and temperature, and that you can avoid unnecessarily high internal pressures and temperature by leaving the throttle wide open and not reducing RPM by mutch in the climb. And such is the extent of the APS deception that all of the available aircraft engine monitors on the market have been programmed - much like Volkswagen emissions test fooling software - to show this.

Don't fall for it!

[Ilikeflying]

Aren't we supposed to only maintain max power for 3 minutes before the engine explodes?

So confusing :(

[The name is Porter]

Pelicans Perch is still available online, do yourself a favour :ok:

[Car RAMROD]

So before (well, currently in many aircraft!) all this whizz bang all cylinder monitoring, how did someone run the engine properly/safely?

If the aircraft has that gear but you don't know how to use it, how are you meant to run the engine?


AFM figures surely.


Please forgive my snobby turbine brain. Pistons were so a decade ago!

[Capt Fathom]

I've spent many years flying around with just the basic engine gauges and never had any problems with the engines, running them as per the Poh.
And that includes several types with geared super/turbo charged engines!
Maybe I am just lucky...perhaps!

[FoolCoarsePitch]

So before (well, currently in many aircraft!) all this whizz bang all cylinder monitoring, how did someone run the engine properly/safely?

If the aircraft has that gear but you don't know how to use it, how are you meant to run the engine?


AFM figures surely.


Please forgive my snobby turbine brain. Pistons were so a decade ago!

The old saying goes 'you don't know what you don't know'. You can forgive someone for being none the wiser however you have your head stuck so far up your ass its no surprise that dealing with your own ignorance isn't high on your priority list.

Given you're such a wise guy why don't you explain how the laws of chemistry and physics change when the AFM of the 520 powered Malibu mandated LOP operation or AFMs of Navajos permit LOP operation?

I mean, its in the AFM right? You'd would have been a pretty rad driver of one of those Malibus because people died from not following that one.

[Car RAMROD]

Wow did I hit a nerve with you FCP!

Never flew a Malibu or a Navajo, so sorry buddy your outta luck getting me to explain them!

Yeah I'm a bit of a wise guy, like pulling the piss but wow. Did I get a nerve!


Ok to be serious. How were things done before full engine monitoring on pistons? I never had monitoring on pistons and ran them as per the AFM. Is there something wrong with what is published in AFMs and all this APS stuff knows better?

I'm not debating that with new technology that there aren't benefits. I just wanted to debate the aspect of "what do you do if you don't have fancy gear?" and also point out that turbines aren't as basic as the original comparison was made. Obviously that point was lost on you. Thank you for having a jab at me rather than answering my questions!


And back to not being serious.
Having ones head up their arse (that's correct, arse, not ass) is good. Don't see the rest of the crap in the world :ok:

[Band a Lot]

I will just make the title of topic more accurate -


Pilots who don't know about engines and/or their airframes as related.

[LeadSled]

Ramrod,
What these guys are teaching is anything but new.

In fact, it was all well known by the end of WWII and into the 1950's.

Somehow it all got lost over the years, and in Australia in particular, from about the 1980s on, general ab nitio teaching of engine handling varied from bad to appalling.

Indeed, so bad was the teaching, that you came across such modifications (with DCA approval) of mixture controls disconnected, and carb. heat locked in ON. Such helpful "rules of thumb" as "no leaning below 5000' AGL" ---- pity about the density altitude on a hot summer day, at some of the more elevated of our airfields.

Do yourself a favor, read everything you can off Pelican, and get to one of the courses. Ignorance is never very attractive, in aviation can be fatal.

CleartoEnter,
Nothing "wrong" with the "recommendations" , which are that, recommendations, not limitations.
Re. Best Economy, that might be theoretically correct, but very touchy. Worked great on the Qantas "Double Sunrise" services during WWII --- but not recommended for other than extreme range for the fuel available.
The 50 rich of peak is the one that will getcha!! Around there is going to maximize the possibility of detonation.

Tootle pip!!

[captjns]

I don't understand the controversy, suppositions and what not in this thread... Lycoming, Continental, and Pratt & Whitney (Round motors that is) have been in the industry a long time... written good manuals and with proven procedures and operational techniques.


True, Lycoming and Continental have evolved with water cooled, single power lever/condition lever applications. But at the end of the day... if you stick with their procedures... you'll reach TBO without issues.

[Eddie Dean]

That's sound reasoning, captjns, it would appear some are posting from a private ops perspective rather than as the OP stated commercial operations.

[Lead Balloon]

That's a good point, Eddie. Engines and the laws of physics know when an aircraft is engaged in private operations versus commercial operations, and change accordingly.

Captjns: Most of those great manuals 'allow', and some and even 'recommend', setting EGT to 50 degrees F on the rich side of peak in the cruise. Aside from the fact that a single point EGT gauge leaves you blissfully ignorant of where on the lean curve each cylinder happens to be, 50 degrees F on the rich side of peak is just about the worst place to set mixture if you want to avoid exposing the cylinders to unnecessarily high pressures and temperatures. The laws of physics and chemistry, backed by data from millions of hours of operation, prove it. As I said earlier and now for the last time in this thread:The fact that the engine might survive the abuse or inefficient operation proves nothing, other than that many engines are manufactured with wide tolerances for abuse and inefficient operation.

A comparison between the condition and costs of running engines the blissful ignorance way, on the one hand, and the condition and costs of running engines on the basis of the science and data used by APS, on the other, is quite instructive. But only for those who are willing and able to learn.

[Adsie]

tio540

Not a truer bunch of words said

[Car RAMROD]

Leadie, I'm not spending my money and time to go on an APS course. I'll get zero benefit other than be able to possibly argue their point of view to all and sundry. I did read those pelican things years ago though. If anything I found them thought provoking rather than gospel. There's lots of information out on the web and published books about other aircraft and engines, also written by very experienced and technical people (development test crew), thought provoking too but still not gospel.

If however, I operate pistons again then maybe I'll look to build on what I learnt about piston engines all those years ago. But until then, zero benefit from an APS course.

Yes I was told things like "don't run over square" but I did it anyway. Why? Because that power setting is in the aircraft power chart! My engines have made TBO (and beyond) without the fancy equipment, so operating as per the AFM seems to be good enough!

There does also seem to be a bit of a demarcation between the private and the commercial operators here. Private owners don't exactly have to worry about fronting court for someone else operating outside of the approved procedures and crashing a plane/killing people!

[Eddie Dean]

RAMROD. I like the mult EGT or CHT (or both) as a diagnostic tool.

[Ultralights]

If however, I operate pistons again then maybe I'll look to build on what I learnt about piston engines all those years ago. But until then, zero benefit from an APS course.

dont they offer a 100% money back guarantee if you feel you gained nothing from the course?

and since when has any education been of no benefit? i am willing to bet i could tell you more about your engine by doing a mag check at cruise power at TOD than you could ever gain by doing the same at runup.

i have done the course, and fly behind non mixture equipped aircraft 90% of the time, and when i am flying anything Lycombing or Continental powered, its only fitted with a single EGT probe, and the lessons learnt at the course help me understand whats going on with those aircraft as well.

[Aerozepplin]

There are, or at least were major commercial operators in New Zealand who operated LOP. I don't know if they still are but when I talked to a former senior pilot he was pretty proud they did.

The argument to the POH argument is that it just says "recommended" best economy and best power. It doesn't say you can only operate at "best economy" or "best power", because often you can't, takeoff for example. So if you can operate richer than those, why not leaner?

I know that some POHs have said said no LOP (or was it separate Lycoming advice?) Anyway, the funny thing is, as I said before if I used the "lean till rough then enrich till smooth" i'm running at least some of the cylinders LOP. Am I operating illegally?

I bet if I offered most of you a homeopathic remedy you'd point out that the data doesn't support its effectiveness. Well, likewise the operation of an engine at 50 degrees ROP. The data shows it is the worst position. Simple. Manufacturers are like regulators and move at the speed of roading tar, so the pressure from people who have gathered real hard data are in my mind of a similar value to those who pressure for regulatory reform.

[scavenger]

From Jabawocky in an earlier post:

I can teach anyone to fly safely LOP in under 5 minutes, more like 2-3 minutes including a briefing and demonstration. Mid 2013 during the Aust Womens Pilots conference in Hervey Bay, I took Kreisha Ballantyne, the editor from Australian Pilot flying over Fraser Island. I asked her to fly, and we departed YHBA climbed to 1500' and head rougly towards Lake Mackenzie. Once at 1500 and already over water, I gave a briefing on how to do it, with her eyes closed (1-2 seconds) she did it. This was all done and dusted before we reached the Island shores. She nailed it first go. Simple as that, even a girl can do it we joked! We did not need or use anything of the EMS, no lean find functions, nothing more than the human sensor pack and a 1-2 minute briefing.

To shut the naysayers up, could we get the explanation of how to fly LOP without instrumentation and with eyes shut?

From the same post:

One thing I and Mr Atkinson, Braly, Deakin and Denyer promise is that if someone is actually willing to learn and shows signs of being determined to learn, despite the strongly held beliefs we were all once taught, we will do our best to share the education. This is not at all about being in pi##ing contests.

A bit of education here on how to fly LOP without instrumentation and with eyes shut may go along way to preventing these stupid threads that pop up, funnily enough when there's a course on soon with a few spots left...

[wishiwasupthere]

You won't get it Scavenger. The snake oil salesman want you to pay up to get in on their good oil.

I'm not really sure what the mods are thinking when the OzRunways/Avplan guys who post on PPRUNE get shut down at any hint of advertising, yet with clockwork regularity these guys pop up to spruik their wears under the guise of 'trying to spread the good word' and get away with a bit of free advertising at the same time.

:ugh:

[Lead Balloon]

That's right, those APS guys are making a profit out of the courses. It's no wonder they sprulk (sorry ... spruce) them. The presenters had hoped to get real jobs and amass some real wealth, but failed at that and now need to rip off course attendees.

LOP with your eyes closed and without instrumentation?

A lot of those fantastic manuals for simple piston aircraft say the leaning procedure is to lean until the engine 'runs rough' and enrich to remove the roughness.

After complying with this procedure in the manual - to stay legal and safe of course - where on the lean curve is each of the cylinders?

When you use the same procedure 'cause it's in the manual for a different aircraft with a different engine to stay legal and safe of course - where on the lean on the lean curve is each of the cylinders?

Do you need your eyes open to feel roughness?

It's all part of the joke that just keeps on giving. :D

[scavenger]

A little defensive there, lead balloon. It was a simple question I asked (without mentioning manuals, staying safe and legal or whatever) but I'm not sure from your post whether the answer to my question is:

A lot of those fantastic manuals for simple piston aircraft say the leaning procedure is to lean until the engine 'runs rough' and enrich to remove the roughness.


or something else. Is this what is taught at the course or not? Could you elaborate please?

Actually don't bother, Jabawocky seems to be straight up so I'll wait for him. This isn't the first time supporters of the APS course have, in their hubris, made the course look less attractive to the disinterested observer.

[wishiwasupthere]

It's the arrogance of a perception of knowing better than everybody else.

[Lead Balloon]

You're not a disinterested observer at all, scavenger. Your posts reveal that you're critical of what you perceive to be a marketing trick.[T]hese stupid threads pop up, funnily enough when there's a course coming up with a few spots left... :=

The value of the course is affected by the hubris of some previous attendees?

The joke just keeps on giving! :D

[FoolCoarsePitch]

You guys realize that after they pay for the venue, catering, & logistics etc, the presenters make no money out of it.

It's ok guys, I'd also be pretty peeved off if I went through a whole career believing and propagating old wives tales about engine management only to be told it was all a lie. Peeved off, but I wouldn't be in denial. I also sure as hell wouldn't be accusing the ones sharing their unbiased data with me as trying to profiteer.

[Car RAMROD]

Umm, I fail to see (pun intended), how leaning with your eyes closed and not watching (therefore effectively not having) the engine monitoring gear gets you the correct lean settings. To me that sounds like just as much guesswork as lean till rough then enrich a bit.

Maybe jabba was watching the gauges and told the lady with her eyes closed "that's correct stop there". Learn to do it in 2 seconds, doesn't sound like it's all that difficult compared to these monkey brain turbines :E


Ultralights, I very much agree that going to courses, diving into extra material, publications etc for developing ones knowledge is paramount. I've just stated that for me, courses on things that I don't operate now nor intend to operate anytime soon are pretty much pointless. It's like you going to a course on Airbus or Boeing systems if you don't fly it nor intend to fly it!
By the way, it isn't possible to mag check my engine :)

[scavenger]

Lead Balloon, since you are quick to point out someone else's incorrect use of language, allow me to suggest you learn the meaning of the word disinterested. Just because I may be critical of something does not mean I have a personal stake. In fact, isn't one of the arguments used on here that critical thinking is what's lacking in the naysayers.

Just complete the sentence if you can:

The best way to lean the mixture, with eyes closed as Jabawocky claims is easy to teach, is to ________________.

[IFEZ]

Please enlighten me (as a member of the uneducated masses) on the correct leaning technique to achieve your precise lop figure flying a basic a/c like a warrior or even a C152, without any fancy gadgets & gauges to assist you. This is a genuine question - I'm interested to know. If doing it with your eyes closed is the way to go, then you must be doing it by sound. As Ramrod said, the only way that would work is leaning it until it starts running rough and then richen it until it smooths out.
The APS course sounds like a good idea if you are flying a more advanced a/c but I can't see how it could help your average ppl chugging around in his old warrior or C172 with a throttle, a mixture control, a tacho and basic oil pressure & temp gauges, not even an egt gauge let alone probes on every cylinder!

Sorry scavenger, trod on your toes a bit with that post, but looks like we're after the same info!

[scavenger]

No worries IFEZ, you cut to the heart of the matter. Wait for Jabawocky, his answer will be most illuminating I'm sure. A pity some of his humility did not wear off on some of the attendees.

[Lead Balloon]

[A]llow me to suggest you learn the meaning of the word disinterested.Thanks scavenger. I am very much aware of the denotation of the word "disinterested" (and that it is frequently misused instead of "uninterested").

The best way to lean the mixture, with eyes closed as Jabawocky claims is easy to teach, is to:

- in the case of an engine fitted with a CSU, lean until you feel the aircraft decelerate through the seat of your pants [I do this every flight], and

- in the case of an engine fitted with a fixed pitch prop, until the engine 'runs rough' or ceases producing power, and then enrich to remove the roughness or restore power.

The success of these techniques, and where each cylinder ends up on its lean curve, depends on the engine either having left the factory and being fitted in a way that the proper F/A mixture is delivered to each cylinder (a lottery, given the poor quality control of the manufacture of the components that determine these outcomes) or the engine having been set up that way, post-manufacture and fitment (an outcome that I would have thought would be desirable, instead of runnning the engine inefficiently or abusively to cover up the consequences of poor manufacture).

[The name is Porter]

They'll teach you how to fly ROP if you want. Thing is they'll teach you how to do that at temperatures & pressures that are better for your engine :ok:

I reckon Jaba makes a loss on the course, loves a chat does Jaba, reckon he does it so he can have a good chinwag with likeminded people. So if your mind is closed simple, don't go ;)

[Jabawocky]

scavenger,

With a "CONFORMING ENGINE" it is as easy as…….level out in the cruise, (close your eyes for about 3 seconds while quickly moving the mixture leaner. As soon as you feel the deceleration - stop. Open eyes.

Now I do it in the climb if I want to with my eyes open, not because I am any genius but once you have done it 10-20 times you can do it repeatedly. Once you know your calibrated butt is accurate it is hard to get it wrong. If you move the mixture too slowly and/or have your eyes open you will not sense the deceleration and will miss the sweet spot known as best BSFC.

This technique works at 500' and WOT/max rpm or at FL150/xxxx RPM.

Now the hidden question you ask is how do I do it sans an EMS. Well take a carby O-320 RV6 that a Airline guy I know owns, no EMS but we are 100% sure the engine is a conforming one. guess what, the Big Mixture Pull works every time. And yes that is a carby engine.

Of course if the engine was not conforming, it would not do that nicely and you would know.

Let me be clear, the ROP pilot takes off after an annual and the injectors have been out, and it is a TC/TN engine, he flies home with one cylinder leaned out to a ROP setting that is driving that cylinder head pressure and temp up through the roof, and it runs smooth as a babies bottom. No EMS therefore he never knows. But if he was familiar with the BMP technique, the first thing he would do after maintenance is do an orbit over the field and a BMP, if it played nice he would go home either LOP or ROP (both are valid if done right). If there was a F/A ratio issue he would certainly discover it and land asking the LAME to fix it.

Of course having an EMS would make the diagnosis a LOT easier.

So there ya go……ROP pilots actually need engine monitors more than LOP pilots. Add to that once LOP by BMP method, you can't hurt any engine, period. But if you are an uncertain red knob fiddler you can.

Two last points;
A: The APS class is for piston pilots and LAME's. Yes a lot of LAME's have had many great learning experiences, David Paynter from Brisbane Aero, the late Steve Hobson from Bankstown, and about 15 more I can think of.

the class is NOT a LOP class…..I will say that again, it is NOT a class about flying LOP, in fact it would be about 10% maximum. The science of combustion taught with real in cylinder engine dyno data, how that relates to what you see on an EMS, how to manage for best speed/range or whatever in all types of flight mode, how to diagnose the EMS data (and this is where 100% of pilots and LAME's learn the most) and it is where we spend the most time. Plus quite a number of life saving diagnosis in flight topics, and how to save a fortune on maintenance bills by doing the right things at the right time and saving hours of chasing problems rather than going straight to them.

This last paragraph is what the original poster was really thinking I bet. I now know who he is…..good student and great guy :ok:

B: Andrew Denyer, Leisa and myself have yet to take a profit from APS and in fact personally we are out of pocket. We leave any residual funds to ensure the classes are fully funded despite the costs and it is not cheap to put on.

While I can't speak for John George and Walter, I do know that we did the sums one day sitting down with a cold drink in Tennesse or Louisianna, and the hourly rate would be something like a dollar or less. I doubt George has ever banked a cheque, John used to send them. Think he gave up. When you realise the motivation is more about better education with science and the safety outcomes that delivers, then you might understand that profit is not even a thought let alone a motivation.

While I think of it, imagine the satisfaction when you get an email explaining how the lessons learned in class saved a family from grief because they diagnosed and dealt with a problem before it got them over the top of the Rocky Mountains, or even the many smaller helped solve a problem that saved wasting several thousand dollars in chasing it down. Last year I had a lady (over 65) who did the course discover a whole bunch of defects, some her LAME was dismissive of and telling her the EMS was just scaring her. He was wrong, she was right and the things I found were a disgrace. She saved herself thousands, and maybe her life one day as a result.

That folks makes it all worth the hundreds of hours we put in for no financial gain.

When the master class is released we will reinvest in that for the benefit of our students…..engine monitor diagnosis torture is the best way to describe it :E

IFEZ…..if we could explain that in one internet post, do you think anyone would ever come to let alone pay for a 2.5 days brain strain?

Seriously, I do not care whether you fly a Briggs and Stratten powered ultralight or a Chieftan……..the theory is all the same. If you really want a better explanation send me a PM with your phone number and I will happily chat for a bit….typing the Q&A's back and forward will kill my keyboard :bored:

[scavenger]

Thanks for your straight answer Lead Balloon, that's what I was after. I do not disagree in the slightest.

[Jabawocky]

Lead ballon
- in the case of an engine fitted with a fixed pitch prop, until the engine 'runs rough' or ceases producing power, and then enrich to remove the roughness or restore power.

Actually with a conforming engine and fixed pitch prop, like the O-320 I mentioned above, you can simply use about a 100RPM drop before it even runs rough. ;)

Scavenger, if you want my details are in a PM shortly. :ok:

[scavenger]

And thanks again Jabawocky. In fact I do understand you think:

When you realise the motivation is more about better education with science and the safety outcomes that delivers, then you might understand that profit is not even a thought let alone a motivation.

which is why I was sure you would respond in the manner you did. :ok:

If it's costing you money and safety outcomes are paramount, why not post all the course material somewhere free of charge? You'd save a heap, you could still run the course for those desperate to attend, but safety would be improved for those without the time or resources to attend the course.

[megan]

why not post all the course material somewhere free of chargeIt's already available scavenger

"Pelican's Perch" Index - AVweb Features Article (http://www.avweb.com/news/pelican/182146-1.html)

[Jabawocky]

You'd save a heap, you could still run the course for those desperate to attend, but safety would be improved for those without the time or resources to attend the course.

And the online version is available, but it is not mine to give away.

And the classroom environment cannot be beaten. Hey lets ditch flying training right through to operating a jumbo, it can be learned on youtube! :eek: I think you will get what I mean.

[scavenger]

I think you will get what I mean.

Certainly I do, but that does not stop you from posting materials on line for free.

Given that:

And the classroom environment cannot be beaten

do you recommend the online version, or would it be akin to:

Hey lets ditch flying training right through to operating a jumbo, it can be learned on youtube!

In any case, thanks for answering, and if the materials aren't yours to post for free, but only to sell at a personal loss, I now understand your position a little better.

[Squawk7700]

Aerozep, I used to run the IO-240 with Fadec. What's your fuel burn at 75% on the 235? Mine was around 23L. I should research the auto mixture setting on the Fadec in relation to EGT as its automatic and I wonder what it's doing under the hood.

[Jabawocky]

Just remember you can't use EGT as an absolute number, at varying RPM the EGT absolute changes, same for MP, so everything needs to be referenced to peak to be useful as a guide.

Another thing not well understood. And not easy to teach on a forum. :ok:

[Lumps]

yet with clockwork regularity these guys pop up to spruik their wears under the guise of 'trying to spread the good word' and get away with a bit of free advertising at the same time.

I started the thread. Had no idea there was another course on, was just hoping that someone, a few young CPLs or whoever would click and start wondering about exactly what they know, or more what they know they don't know as might be the case, in Rumsfeldian.

I did the course in Perth a few years back. Thing is with the course, you'd only sign up if you were already questioning your known unknowns, which was the purpose of the thread.

squittle pop!

[Squawk7700]

Just remember you can't use EGT as an absolute number, at varying RPM the EGT absolute changes, same for MP, so everything needs to be referenced to peak to be useful as a guide.



If you are referring to my post Jabba, you are absolutely correct. With Fadec, or at least with the Vm1000 display you have little to no information available to you on what's happening, thus I wonder what the manufacturers set it to as they claim with Fadec fitted your engine will run for eons over TBO.

[Lumps]

and just because it seems relevant to the what do you do with no instrumentation theme:

A while back I ferried an agcat to an operator. At 1800rpm and 28" (R985, 55% power) the CHT (single probe) was showing in the redline, from memory it started at something like 210°C up to 280°C (absolute redline for this engine is an astonishing 550°F!) This is a low power setting, and I was getting around 220°C. I think it is because of the complete lack of baffling to direct the airflow to the rear of the cylinders, that's my guess.

Before I did the APS course I would have just sat it there for the next few hours because frankly there isn't much you could do about it. But being a hubristic know it all I thought hang on.. and pulled the mixture back until the seat-o-meter felt that deceleration just so, and added a sprinkle of "MP and voila! CHTs dropped to around 200°C, airspeed much the same. With absolutely nil engine monitoring save the CHT I knew this was a happy, smooth running LOP round engine, just by what the CHT did. Just gotta look at what's printed on the APS T shirts.

Ok to spruik the T-shirts?

(The ag boys didn't like the look of the exhaust pipe at all when I landed, I'm sure they sooted it up soon enough though. Buggered if I know how these engines survive in actual ag operations - slow, no baffling, max continuous power... now there is a good argument for the superior reliability of turbines, compared to what I'm guessing happens to these motors)

[IFEZ]

Thanks Lead Balloon & Jabawocky for your responses.


Jabawocky - PM sent :ok:

[ForkTailedDrKiller]

Three things you should NEVER discuss: Politics, religion and LOP!

Jaba, I don't know why you bother with threads like this. Those that want to learn more about the engines they operate will make up their own minds about whether or not to attend one of your courses, and those that don't ........ well, who really cares!

Dr :8

PS: For the record, I have done the APS course!

[Left 270]

I haven't done the course but I have read all of Deakin's info as well as a lot of others. What seems to be missed by the pilots who haven't read up is that it really has nothing to do with LOP, but correct mixture settings as a whole. I have never ran LOP and unless I end up an owner I'm never likely to.

But, now having the knowledge I operate ROP in a much safer way, I know when to, and how much to lean by and understand why a blanket rule of 50F ROP CAN be abusive to the engine. I have an understanding of what the needles are trying to tell me (yep, those unreliable single point ones, but if it's all you have then it's the best that you can do), and if nothing else, I am now thinking about what the engine is going through after complying with my requested power/mixture settings, rather then setting 50F ROP religiously at all power settings/stages of flight/ conditions etc. So I think even if nothing's changed, because of company SOP etc, the understanding is priceless.

[The name is Porter]

Jaba, I don't know why you bother with threads like this. Those that want to learn more about the engines they operate will make up their own minds about whether or not to attend one of your courses, and those that don't ........ well, who really cares!

And tightarses wanting stuff for free, I spose they run round town giving away theirs and other peoples' property?

[Jabawocky]

Thanks Forkie for the tip :ok:

But really, the last post is more the point, we teach whole of operation by scientific methods as you well know. But the diagnosis element is the big thing. That is where the major benefit is.

Give 99% of pilots and engine monitor and they are a dog watching TV, it is that simple. They might think they know what they are seeing but being able to diagnose with it is another matter.

And I enjoy the banter, there has been not much else of interest on prune in months so it makes a change! :)

[Lead Balloon]

That's because it's the quickest practical way to achieve the scientifically-proven desired setting for a conforming engine, cleared. ;)

PS: The single most important reason for my decision to attend an APS course was the opportunity to meet and draw on the wisdom of a person who's forgotten more about piston aero engine operation than anyone has ever learned in the third world of GA that is Australia - Mr John Deakin. You can't do that by reading on-line materials.

[Eddie Dean]

Clearedtoenter, what page and complete reference please.

[Ex FSO GRIFFO]

I get the same 'feelings' with every landing in the Tiger Moth......'specially in a > 15Kt X/wind......

Cheers..Lots of 'em..:ok::ok::ok: To ALL who fly 'Tigers'....

[gerry111]

On to the fifth page and still not a squeak out of yr right. Is he OK?

[Jabawocky]

That's because it's the quickest practical way to achieve the scientifically-proven desired setting for a conforming engine, cleared.

PS: The single most important reason for my decision to attend an APS course was the opportunity to meet and draw on the wisdom of a person who's forgotten more about piston aero engine operation than anyone has ever learned in the third world of GA that is Australia - Mr John Deakin. You can't do that by reading on-line materials.

Well I have just narrowed you down to a list ;) long list…………


clearedtorenter;
Very funny, I admire a good sense of humour. Pity you fail to understand how to apply science in the cockpit. :ok:

But with posts like this;My POH says 'For best economy, operate at peak TIT' (about 9 times actually)
Then it says 'Recommended lean 50F Rich of Peak TIT and 'for best power 125F Rich of Peak TIT'

Anything wrong with my POH?

And along with comments by eddie dean……you start to make very big statements about your lack of understanding of science and POH's and what they really mean, and where/when they are wrong. They can be wrong you know, don't you?

I wonder how many of you have met the guys who have written some doozy POH statements, who have bravely stood up and said "I wrote that and now I am regretting doing so". That is a humbling experience.

Keeping ones head in the sand is a safe and comfortable place to be. Except your ass is rather exposed.

Now let me post this graph for the XXth time and please tell me where best economy is with reference to peak TIT. Is it really 50ROP TIT? Now tell not me, but your prune pears, that your POH is correct. It either is or it is not.

http://i849.photobucket.com/albums/ab58/jaba430/Landmarksgraph_zpsbfb07cbb.gif

Better still, pick up the phone and lets chat about it, I give you a money back guarantee to help you learn. Plenty posting here who know what I am offering, some I am not even sure who they are. Up to you, if you are prepared to put your money where your mouth is. I am and we do.

Cheers :ok:

[bolthead]

Maybe I missed it earlier, what is the definition of a ' conforming engine' ?

[Eddie Dean]

What statement would that be Jaba?

[Jabawocky]

I may have been misreading your previous post, it seemed to be of a mischievous nature. If I misunderstood, then my sincere apologies.

Bolt head, a conforming engine is one that has correctly gapped plugs, resistance below 5Kohms, magneto's in a good state of function and timed accurately to the correct numbers, plus fuel/air ratio's that are near to equal on all cylinders. As the design engineers would want them to be. :ok:

[Stikybeke]

Hey Jabba,

"some I am not even sure who they are"

I think I've identified one and by now the hives must be starting to kick in....

On another note though I wonder if there's a market for applying some of these principles in a linear format to the operation of wind turbines? I read somewhere that the ban on them has been lifted.... Still, interesting stuff all this science of proper engine management and no doubt most contributory to the saving of lives.

Sticky
:ok:

[Jabawocky]

Decoder, the thread that vanished was a mystery, as was the alleged student. I even checked with John Deakin. He could not recall this guy and his alleged claim. That was back in November.

As for this thread you are completely wrong……:= I had no idea about it until I saw it.

Given the amount of free advice and education over the years that George John and Walter have given in many formats, why does it seem bad to let someone know there are 3 places left when it might be helpful to them.

Some of you guys are a bit too over the top.

[Supermouse3]

very few fresh CPL holders know the intricacy's of how piston engines even work, most know just enough to pass the exam but that's the extent of it..
I guarantee most wouldn't be able to change the oil- let alone lean correctly...
probably because a lot of instructors don't know either/ or care...

[LeadSled]

Folks,
To be fair, I know of a few newer generation and older generation pilots who have a very balanced approach, they know sod all about kero. burners, as well as their lamentable knowledge of piston engines, where they all got their start.
Tootle pip!!

[Lead Balloon]

The science shows that running an engine at around 50 F degrees rich of peak results in the highest peak pressures and temperatures for the cylinders.

The science shows that the two biggest factors contributing to cylinder fatigue are pressure and temperature.

The science therefore shows that manufacturers who recommend that cruise EGT be set around 50 F degrees rich of peak were either ignorant or, as is more likely, trying to wring as much power as they could out of the engine in marketing competitions that used to be won on the basis of a couple of knots cruise TAS in a sidebar summary in the aviation magazine reviews of the latest model Cessna/Piper/Beechcraft etc.

The science therefore also shows that a person who considers POHs to contain immutable facts and the safest engine management procedures is the person with the religion problem.

(And science also shows why the deceleration felt through the seat of the pants is a reliable, repeatable and safe way of setting cruise mixture lean of peak on a confirming engine fitted with a CSU.)

[Eddie Dean]

Can I get a hallelujah, can I get an Amen.
Come one come all to the altar of the APS God.

[Ultralights]

Can I get a hallelujah, can I get an Amen.
Come one come all to the altar of the APS God.
is this implying that al the info in regards to LOP ops and running 50Def rich are based on faith??

its actually hard science.. nothing religious about it.

[Eddie Dean]

Agnostic I am being. Is APS halal then🍺

[sheppey]

probably because a lot of instructors don't know either/ or care...

Alarmingly true statement. If you are a student pilot try asking your flying instructor (in fact any flying instructor) how he would teach a go-around from a full flap landing at the flare. Type specific of course. Remember this is quite a critical manoeuvre for a new student especially as he/she is about to embark on first solo. Write down the instructors personal opinion.

Compare his step by step answer against the manufacturer's Pilot Operating Handbook. In the Cessna POH it is termed Balked Landing

Similar exercise on the meaning and practical use of Minimum Static RPM. Where is this figure normally located for reference?

Chances are it will shatter your confidence in the instructors knowledge...

[IFEZ]

Sheppey, are you speaking from personal experience? Seriously, those things you mention are BAK/GFPT stuff (or whatever they call it now). Or at least they were back when I did my initial training.

What go-round procedure have you been told or heard is being taught that is so different to the POH..?

If what you say is true, then standards must have slipped somewhat. I'd have been disappointed if one of my students couldn't answer those questions let alone an instructor!

[Tinstaafl]

re. aircraft manufacturer's engine operating *recommendations* (not limits): Nothing in the POH says that the engine is guaranteed to make TBO if the recomendations are followed. Similarly, no certification regulation specifies that TBO must be guaranteed. Those recommendations are purely to make the POH performance numbers.

In a similar vein, think of the old turbo F1 qualifying engines: 1200HP from a forced induction 1.5L engine - and it was toast after one round of qualifying - but, jeez, the performance was fabulous. Great for advertising capability. Meanwhile, the same engine producing only 800HP would (usually) last an entire race but performance was rather lower. Much like POH engine operation to achieve POH performance figures, vs LOP ops to maximise engine life.

[Eddie Dean]

Just now re-reading the Lycoming Flyer on Engine operations.
Talks about engine run in, EGT, CHT, LOP,ROP.
Perhaps worth a read before you kneel at the altar of APS.

[Trent 972]

Commercial Pilots...
While not knocking APS at all because the people who run it are good and decent knowledgable people, I can't help but wonder that all the APS learning is predicated on a "Conforming Engine".
Where can a Commercial pilot, operating possibly many different engines concurrently, find a data plate (or whatever) that says the engine is a "Conforming Engine"?
Seems to me that private owners who know the ins and outs of their own engine would benefit a lot from an APS education but commercial pilots in and out of different machines on a daily basis would be hanging themselves out to dry by not heeding the OEM procedures, without knowing they were operating "Conforming Engines".

[Lead Balloon]

It would be a good start if they had an understanding of what those curves jabba has posted many times actually mean, and the profound implications for piston engine management. A pilot with that understanding would not have operated the engines on the Whyalla Airlines aircraft in the climb in the way they were. :ok:

[Aussie Bob]

What LB says, plus you can get an idea if an engine conforms by leaning in the cruise at say 65% or less. If it runs rough around peak EGT it is unlikely it conforms. If you can lean it past peak EGT and beyond until it looses power and there is no rough running, it likely is a conforming engine.

I reccomend the course, either online or with Jabba. For most pilots, there is heaps to learn.

[Lead Balloon]

Whyalla was a tragically sad set of holes in the Swiss cheese. The latent manufacturing defect in the crankshafts may not have caused a failure, if the leaning procedure for the climb had kept the mixture sufficiently rich of peak.

A pilot with knowledge of what the curves mean would never have adopted the leaning procedure for the high power climb as was the practice at Whyalla, irrespective of what some idiot regulatory or manufacturer's document might have allowed or mandated.

A knowledge and understanding of what the curves mean, and of what the data show, gives you a chance that you might actually comprehend that if you are going to operate rich of peak, you have to set the mixture sufficiently far rich of peak, otherwise you're giving the engine (including that potentially defective crankshaft) the hardest beating you can give it.

It used to be called "airmanship".

[Ultralights]

Seems to me that private owners who know the ins and outs of their own engine would benefit a lot from an APS education but commercial pilots in and out of different machines on a daily basis would be hanging themselves out to dry by not heeding the OEM procedures, without knowing they were operating "Conforming Engines".

I have done the APS course, and i own and operate a lot of aircraft that have no mixture control at all, and those that arnt rotax powered, are aircraft with only 1 CHT and 1 EGT probe,
a relatively small percentage of the course focuses on EGT and LOP ops, the rest is how you can interpret that data you can get from those indicators, and understand the causes, and reasons behind those readings, and how to understand just what is happening with that engine. sure, do your runups and mag checks at low power before a flight, but what can you learn from that? sure, you can determine a dead Mag, but thats about it, after the course, you will learn just how much more info you can find out, and why doing a mag check at top of descent will reveal a lot more than just "A dead mag" you will know how to identify a failing plug, which cylinder its in, and upper or lower plug, so it can be changed before it fails..

a good analogy would by your ab initio training, the LOP ops will be the straight and level component only, but the whole course is similar to your complete PPL training, its not just LOP, its all about engine management and understanding what the engine is telling you..

how many pilots have been to different schools to learn different skills? or have just been to the one school only?
i went to another school to do Aerobatics, Advanced aircraft control and formation, i learned a lot of stuff, and had to UN-learn a lot of incorrect stuff, same with the engine course, i thought, operating an engine with no mixture, i knew all there was about it, and again, i had to unlearn a lot of obviously false info, and relearn from hard data, and also learnt a lot more about engines in general..

[Jabawocky]

Trent
Commercial Pilots...
While not knocking APS at all because the people who run it are good and decent knowledgable people, I can't help but wonder that all the APS learning is predicated on a "Conforming Engine".
Where can a Commercial pilot, operating possibly many different engines concurrently, find a data plate (or whatever) that says the engine is a "Conforming Engine"?
Seems to me that private owners who know the ins and outs of their own engine would benefit a lot from an APS education but commercial pilots in and out of different machines on a daily basis would be hanging themselves out to dry by not heeding the OEM procedures, without knowing they were operating "Conforming Engines".

With appropriate knowledge and engine monitors any pilot be they private owners or commercial operators can tell if they have a conforming engine. There area few commercial operators, some who watch these threads in silence who have fleets of piston aircraft that ensure they are all operating conforming engines all the time.

It is not hard to do. Problem is you need pilots AND LAME's who care enough to use science and not OWT's to achieve it.

The definition of a conforming engine is simply one that is as it should be. The details of this myself and others have done to death already.

UL and AuBob are on the money.

[A Squared]

Commercial Pilots...
While not knocking APS at all because the people who run it are good and decent knowledgable people, I can't help but wonder that all the APS learning is predicated on a "Conforming Engine".
Where can a Commercial pilot, operating possibly many different engines concurrently, find a data plate (or whatever) that says the engine is a "Conforming Engine"?


Umm, I think you're reading just a little bit too much into the word there.

It simply means an engine which conforms to the type certificate, as amended by STC. That is to say; is within overhaul limits, had been maintained according to the manufacturer's instructions, and hasn't been modified outside the manufacturer's Specs.

IOW, in the US at least, any engine in commercial service would be a "conforming engine" unless it had undocumented modifications.

For example, a Ly-Con competition engine would not be a "conforming" engine, as they make modifications like installing high compression pistons not covered by the type certificate of subsequent STC. But then, you won't find a Ly-COn non-conforming competition engine ine an aircraft in commercial service, because it's not permitted by regulation.

[A Squared]

Noone seems to be denying that that maybe the case, but the rediculing and (almost) religious persecution of persons who don't wish to do 'the course' as ignorant and lacking in understanding of the 'science' and further lambasting new and old CPLs as morons is religious fervour gone mad!

This bit bears repeating, and reflection by some here.

I am by no means anti-LOP. I've been reading Deakin's Articles since he first appeared on AVweb, long before the creation of APS. I have also flown DC-6s 6000-ish hours ... All lean of peak (in cruise, anyway) I also ingorperate elements of such into my own personal flying. So, I'm definitely not one to argue against LOP. But I do agree that it is pretty discouraging to see that the LOP fanatics here somehow seem irresistibly compelled to be insulting and denigrating to those who disagree with them, or have not yet been convinced.

As a side note, having seen Mr Deakin in action on the old Avweb forums, I know that he makes a point of being calm, rational and pleasant even in the face of provocation and would be very much against the approach seen here of insulting those who disagree with you. Kind of ironic, really.

[Clare Prop]

I remember coming to Aus and being told that I HAD to set 23"2400 rpm in the cruise under ALL density altitude conditions because "that is the way we do it here in Australia" and if the MAP number exceeded the RPM number divided by 100, the engine would be "overstressed". So we sat in the aircraft and I asked the instructor why, with 29" and 0 RPM the engine wasn't in smithereens...silence. I asked for the power setting tables and got a blank expression. Full throttle height? :confused::confused:

Having flown turbocharged pistons before coming to Aus I was astounded...then all was revealed when I asked for the POH for a new type and was handed one of those black A5 "Aircraft Flight Manuals" I understood why the OWTs were so prevalent in this country. CASA had completely re-invented the wheel, information simply wasn't available and even though POHs are back some of those OWTs are STILL around. :mad::ugh:

[A Squared]

...then all was revealed when I asked for the POH for a new type and was handed one of those black A5 "Aircraft Flight Manuals"

Hmmm, tell me about these. Sounds like an Australian thing? Not being an Aus pilot, not quoite sure what you're referring to.


FWIW, the Engine manual for my airplane (C180 with O-470R) recommends setting the lowes RPM at which the engine will run smoothly, which is alway much less than 100XMAP in Inches hg.

[Lead Balloon]

Who are the "LOP fanatics" you are referring to, A squared?

[A Squared]

Well, since you ask, you specifically, seem to be one who is unable to resist sneering at others who don't share your views. You're not the only one by any means.

[Lead Balloon]

You are mistaking my general obnoxiousness for being an "LOP fanatic".

I am not an LOP fanatic.

I am, in essence, merely pointing out that pilots who don't know how to run piston engines as efficiently and safely as practicable, and don't want to find out how to, fail airmanship 101. :ok:

[A Squared]

Okay, perhaps "fanatic" was a poor choice of words. How about "advocate" ?

[Lead Balloon]

I "advocate" running piston engines as efficiently and safely as practicable. (After all, that is the definition of airmanship, is it not? Safe and efficient operation of aircraft etc...)

Sometimes that means running the engine sufficiently ROP.

Sometimes that means running the engine sufficiently LOP.

Sometimes that means running the engine at peak EGT.

It always means understanding why.

[Clare Prop]

A Squared, when I got here in the early 90s, aircraft had a little A5 booklet thingy that had replaced the POH, it had some take off and landing charts (different to the manufacturer's, eg those boxy things for Cessnas instead of the manufacturer's tables, which AFAIK are STILL in the PPL exam!) and told you where the green arcs were on the T's and P's gauges. The rest of the pages were usually missing. If you were lucky it had the weight schedule and some strange Australian version of the loading charts. It had none of the standard layout of a POH and no useful information on the aircraft systems or normal operating procedures but (I was told) had superceded the POH.

I'm sure there is someone here who was around when they were introduced and can tell us what the reason, apart from the Australian necessity to reinvent perfectly good wheels, was for these things?

[gerry111]

'A Squared',


'Lead Balloon' is a rather private PPRuNe character. But I sometimes think that he may indeed be the guy that I've been safely going flying with on GA adventures for the last 30 years.


I'm also convinced by the APS science regarding LOP operations..


Like 'Lead Balloon', I reckon that if you really understand how your aeroplane, engine and systems really work then you have a safer operation.

[Trent 972]

Thanks Jaba
....With appropriate knowledge and engine monitors any pilot be they private owners or commercial operators can tell if they have a conforming engine....
I think you and yours offer a really good learning experience, for the suitably equipped engine owner.

[A Squared]

I'm also convinced by the APS science regarding LOP operations..


Like 'Lead Balloon', I reckon that if you really understand how your aeroplane, engine and systems really work then you have a safer operation.

I think you completely missed the point of my post.

[Jabawocky]

TrentI think you and yours offer a really good learning experience, for the suitably equipped engine owner.

Thank you :ok:, but let me expand a little further. For the suitably equipped engine owner, I read that as someone wh themselves is suitably equipped, not with knowledge but rather understanding.

With that understanding it makes it possible to work with a non instrumented piston engine, like my CASA friend and his cardinal. That was eye opening for him. Like the RV6 mentioned before, it means you are having to do mental representation a bit, but it sure beats a cook book.

Speaking of cookbooks. I have been talking to a Cessna TTX pilot of late. The POH is far better detailed than many early POH's but my critical assessment is they tried to make a recipe book of it and have left some dangerously vague info in there.

As is typical, the optional LOP operation is described by pages and pages of tabulated LOP fuel flows. Seriously even I glazed over and refused to study them. The simplest and safest side of the EGT curves has been over complicated by this mess that will most likely have pilots head down in a book for hours instead of flying the damned plane.

On the other hand for recommended cruise it says this;
CRUISE
1. THROTTLE Control - ADJUST (no more than 85% power
recommended)
2. PROPELLER Control - ADJUST (no more than 85% power
recommended)
3. MIXTURE Control - LEAN AS REQUIRED
NOTE
Set T.I.T. indicator to 1625°F for Best Power or refer to
Section 5, Performance, Lean-of-Peak Cruise Performance
charts for chosen altitude.
4. Elevator and Aileron Trim Controls - ADJUST
5. RUDDER HOLD Switch - ENGAGE (as desired)
6. OXY QTY Pressure - MONITOR QUANTITY (if in use)
7. OXY OUTLET Pressure - MONITOR PRESSURE (if in use)

This is where the pilots are picking up a simple set and forget, at 80-85% power, and what do you know, this will be roughly 75-125dF ROP. :ugh:

The one side of the curve on a turbocharged engine which can stress the engine (not destroy it instantly) and the best they can do is write that. Yet the safest side of the curve gets 13 pages of tables. I will concede that the ROP tables are the same, but that is where performance and range needs more complicated data. The problem is they tabulate BEST POWER mixture from 90+% downwards. Think RED BOX.

I need a BEX and a good lie down :}

All engines deserve an EMS :ok: And then there is a chance somebody can use the data for useful purposes.

[A Squared]

Speaking of cookbooks. I have been talking to a Cessna TTX pilot of late. The POH is far better detailed than many early POH's but my critical assessment is they tried to make a recipe book of it and have left some dangerously vague info in there.

Unfortunately, a manufacturer's POH pretty much has to be a bit of a cookbook. That's reality. Mind you, I'm not anti-LOP/advanced engine management in any way. However, the guy writing the POH cannot assume that the reader is knowledgeable about internal combustion theory, nor can they include a large tutorial. If your POH contains all the necessary background material to understand the techniques from the AP seminars, there's going to be a whole bunch of pilots who aren't going to read it, or are going to read it and arn't going to understand it. Like it or not, a manufacturer really has to aim for the lowest common denominator with a POH, with something along the lines of: "if you follow these steps and observe these limits, you will achieve an acceptable result". perhaps the examples you cite could have been executed better, but I don't think you're ever going to get away from a cookbook format.

[Jabawocky]

A2

I understand what you mean, and yes they could have done a lot better. I could have done it in probably 2 pages (not 26), achieved a better result and been simpler to extract the range data etc. That would mean greater safety outcomes.

If I had nothing to do and was bored I would have a go at it for giggles. :8

By the way, and I expect you know this but APS is all about critical thinking and application of science and data. The rest is what people think its about. :ok:

Cheers!

[The name is Porter]

I have been talking to a Cessna TTX pilot of late.


I've heard that pilot is smokin' hot!

[Jabawocky]

THAT TTX pilot……she is, but here boyfriend is a tosser :} And by Sunday WAY TOO old for her. :E

[The name is Porter]

Used to be a tosser :E And Sunday doesn't change anything ;) :E

[oggers]

Jabawocky

I can teach anyone to fly safely LOP in under 5 minutes, more like 2-3 minutes including a briefing and demonstration....it is as easy as level out in the cruise, (close your eyes for about 3 seconds while quickly moving the mixture leaner. As soon as you feel the deceleration - stop. Open eyes....This technique works at 500' and WOT/max rpm...how do I do it sans an EMS, the Big Mixture Pull works every time. And yes that is a carby engine.

That claim does not exactly dovetail with information on the GAMI website:

Not all GA engines can run safely LOP. Carbureted engines, for example, lack precise fuel/air metering systems and typically run rough and lose power LOP. And electronic engine monitors that show cylinder head and exhaust gas temperatures for every cylinder are necessary for safe LOP operations. Graphic engine monitors are even better.

...carbureted engines, and those without engine monitors, can and are being damaged from pilots running them too lean. “We’ve never had any issues with lean-of-peak operations in engines equipped with GAMI injectors and graphic engine monitors,” Middlebrook said. “But we’re also seeing burned valves and cylinder damage in carbureted engines or those with single-point EGTs trying to fly lean of peak. If you don’t have matched fuel injection nozzles and a six-point engine monitor, you just don’t have enough information for lean-of-peak operations.”

[Lead Balloon]

That's because many engines come out of the manufacturer or maintenance shop with poorly set up fuel/induction systems. Staying ROP helps to cover up the poor quality.

The curves Jabba has posted many times shows why: The slope of the power curve LOP is steeper than ROP, and therefore differences in the power output of each cylinder as a consequence of the imbalances in F/A in to each cylinder become more evident LOP. "Lean misfire" and "roughness" while leaning is actually vibration caused by the imbalance in the power outputs of different cylinders.

The term "conforming engine" is shorthand for one that's been set up properly. That said, my understanding is that some carbureted engines are notoriously difficult to run smoothly ROP, because there isn't much that can adjusted to deal with imbalance problem.

Some people are happy to throw fuel at the problem caused by poor manufacture or maintenance. That's their decision. The main safety message they need to understand is the need to ensure all cylinders are operating sufficiently ROP. That's because the setting that puts the cylinders under the most pressure and temperature stress is, in fact, a setting ROP: around 50 degrees F ROP.

That's also why an engine monitor is important, even if you don't want to operate LOP.

[oggers]

Lead Balloon

"Lean misfire" and "roughness" while leaning is actually vibration caused by the imbalance in the power outputs of different cylinders.


Sure but that is the basis of my point, not an answer to it.

many engines come out of the manufacturer or maintenance shop with poorly set up fuel/induction systems...The term "conforming engine" is shorthand for one that's been set up properly

Yes, but:

"even if you have a brand new perfect factory engine, that has a perfectly calibrated set of factory fuel injectors in the engine, with a perfect set-up on the fuel system, the engine is still not going to run smooth" (George Braly, GAMI)

So how do you get a carburetted engine with "fuel/air ratio's that are near to equal on all cylinders", ready for jabawocky's 'eyes closed, big mixture pull, feel the decel = safe LOP even at 500'/full power, engine monitor not required' technique? Genuine question.

Here is a selection of quotes from the GAMI website:

"Not all GA engines can run safely LOP. Carbureted engines, for example, lack precise fuel/air metering systems and typically run rough and lose power LOP

...it's not just a matter of pulling back on the mixture. The airplane and engine must be properly equipped for lean of peak operations otherwise you can do serious serious damage to the engine..

You need balanced fuel injectors and a good multi probe engine analyser that shows EGT and CHT for all the cylinders. A single probe EGT/CHT set-up is just not acceptable

If you don’t have matched fuel injection nozzles and a six-point engine monitor, you just don’t have enough information for lean-of-peak operations."

[extralite]

Really enjoyed the various viewpoints. Most of my experience is on turbo props but now owning an IO360 trying to learn as much as i can. I have been setting 25/25 in the climb! I have been keeping CHT under 390 in climb so hopefully not too much problem.

Is this a summary of the 7 pages?

Almost everyone agrees 50 degrees ROP is a no-no because that will correspond to highest CHT and pressure.

If running ROP, just need to make sure it is at least more than 50 degrees, more like 100 degrees?

Running LOP is more controversial but has advocates.

I am not understanding the alternative climb settings that well. Seems to be pretty much high RPM settings and higher throttle settings, within CHT limits?

[LeadSled]

Running LOP is more controversial but has advocates. (http://www.aph.gov.au/Senator_Sterle)

Extralite,
The above against LOP are contributions to the discussion by the ignorati.

LOP was SOP in all large piston engines, and until recent years, was well covered in the Lycoming engine handbooks --- which went into detail not necessarily to be found in the particular aircraft AFM (by whatever name).

The objections to LOP are a measure of the dumbing down of aviation knowledge.

Tootle pip!!

[extralite]

At the very least this is confusing. The "Continental Guide on Engine Care" seems to suggest that in most cases, we do what this thread seems to suggest we don't, ie run at 50-75 degrees ROP. LOP can be used on some engines for longest range but requires careful monitoring. Is this outdated info?

from "Continetal Guide on Engine Care." http://www.insightavionics.com/pdf%20files/Continental.pdf

High Power Cruise
High power cruise is generally defined as power settings between 65 and 74% of rated engine power. In this
range, TCM recommends the fuel mixture be leaned for “best power” settings (see chart on page 27). This can be
done by leaning to the values in the POH, or if EGT information is available, lean the mixture by finding peak
EGT and adjusting richer to get to best power. The leanest cylinder EGT (first to peak) should be at least 50°F
rich of peak, preferably 75°F rich of peak. Since a 75 to 100°F EGT spread is normal, a single point EGT system
should be adjusted to at least 125°F rich of peak. Multi-point EGT systems should be adjusted so the cylinder
with the leanest (first to peak) EGT is 50 to 75°F rich of peak. For turbocharged engines, TIT limitations may
restrict leaning. In those cases, comply with the AFM/POH instructions.
27
TM
Lean of peak operation in the “best economy” range as shown on the “Cruise Power Settings” chart is permitted
on many models and should be used primarily for trips where extended range is desired. Lean of peak operation
requires the operator to monitor EGT closely, as power and temperature may change rapidly in response to small
changes in fuel mixture. Adjust single point EGT system’s cruise mixture 50° to 75°F lean of peak. Adjust Multipoint
EGT systems so the richest (last to peak) EGT is 25° to 50°F lean of peak. Note on the “Cruise Power
Settings” chart that lean of peak operation reduces power by up to 10% at the same RPM and manifold pressure
setting. Do not increase manifold pressure or RPM to “regain” reduced power or speed. The result is the same as
leaning from a higher power setting. You may also notice in the “Cruise Power Settings” chart that part of the
perceived fuel flow reduction operating at “best economy” comes simply because the power is reduced.

[Ultralights]

High Power Cruise
High power cruise is generally defined as power settings between 65 and 74% of rated engine power. In this
range, TCM recommends the fuel mixture be leaned for “best power” settings (see chart on page 27). This can be
done by leaning to the values in the POH, or if EGT information is available, lean the mixture by finding peak
EGT and adjusting richer to get to best power. The leanest cylinder EGT (first to peak) should be at least 50°F
rich of peak, preferably 75°F rich of peak. Since a 75 to 100°F EGT spread is normal, a single point EGT system
should be adjusted to at least 125°F rich of peak. Multi-point EGT systems should be adjusted so the cylinder
with the leanest (first to peak) EGT is 50 to 75°F rich of peak. For turbocharged engines, TIT limitations may
restrict leaning. In those cases, comply with the AFM/POH instructions.

well, Yes, that will give the best power, but also highest cylinder pressures and CHT temps.. but as it says, it provides best power.. best power at the cost of engine longevity.

[Jabawocky]

LOP can be used on some engines for longest range but requires careful monitoring.

This is one of the more interesting beliefs that we discuss in class. The facts are that ROP operations require you to be more careful than were you being LOP.

Until you have watched the effects of mixture control on a well instrumented engine Dyno with say a turbocharged engine fitted up, you will find that a bit hard to accept. Once you have done this and done some serious detonation testing and watched the effect of mixture and detonation, your mind will be changed forever.

There are a few dozen freshly enlightened pilots in the world after last weekend who would fit that bill. ;) Jut like ultralights :ok:

[no_one]

I just fly with a Rotax. It has a throttle that I push in to make the engine noisier and then I go flying.... :)

[Walter Atkinson]

Gentlemen:

Please allow me some observations and explanations:

Reading this thread has thrown me into the "wayback time machine." We had dozens of these threads 15 years ago when we started teaching the APS class. The threads all were like this one: educated, critical thinkers trying to teach those who had relied for years, maybe decades, on what they were taught that was simply wrong, ...and for whatever reason could not come to grips with their misunderstandings.

When we started, we thought we would teach a one day class on engine management. There was NO WAY. It ended up taking 2½ days to present it to make it complete and offer the student a comfortable understanding of the issues at the end of the class. That being the case there is simply no possible way to impart the information on an internet forum. We have given out reams of free information and it is still not possible to fully educate in this manner or with this bandwidth. Sorry. We wish we could. Even the online course is not quite as "complete" in this regard as the live course--at least that what those who have taken both courses tell us.

George is an aeronautical engineer. John is a retired JAL Captain who has flown everything from J-3s to WWII bombers and was a DC-3 and C-46 pilot for Air America in VN. I am a retired dentist who has spent many, many hours in the engine test stand, have flown over 75 different types of aircraft, including J-3s to the B-24 and the C-46 with the big radials. We were all WRONG about a lot when we started this.... like so many on this forum who think they know, but can't support their knowledge with data. ("We've always done it this way and never had any problems" is not proof of anything. It's nice, but it "proves" nothing.)

For George, John and me, we spent a LOT of time trying to overcome what we "knew" to be true that wasn't. It was a painful experience for all three of us to find out that, with all of our experience, what we had believed and were comfortable "knowing" about engine management for so many thousands of flight hours was simply WRONG. It became a soul-searching experience. But, in the trek toward enlightenment and many, many hours in the most advanced engine test facility in the world, we became comfortable relying on the science rather than other people's opinions. The DATA has no opinion or no ax to grind. We will tell you to this day that we do NOT want you to believe us. We want you to believe the DATA. But, to do that, one must be willing to look at the data and challenge what they believe to be true. (Remember, it requires no data or proof to "believe" something. It does require proof to KNOW something.)

George, John and I asked ourselves "How do you know when you are right?" That rather profound question has a telling answer. The only way you can know that you are right is to constantly challenge what you think you know to be true by trying to disprove your position. We have done that and continue to do that through research. As a result, we continue to learn.

The truth is, that back when we were considered "renegades" or "heretics" by the established aviation experts and the local hangar-flying know-it-alls, it was a lot more fun!!! (Our Aussie partners are finding that out!) Now that (at least in the US) we are considered mainstream, engine management experts and a source of solid, fact-based, information about piston engines, it's just not as much fun. The detractors of our teachings have gone on to worry about such things as chemtrails and the like and the forums are far less antagonistic as we have dozens of pilots and mechanics teaching others about what we and they have discovered. The same will happen Down Under--hopefully more quickly than it did here.

We have been offering a $1000us reward to anyone who could present hard, repeatable data that anything we teach is scientifically flawed or incorrect. We want to know if we are mistaken more than anyone else. So far, no one has sent us any data in an attempt to collect the reward.

Our students (of many thousands) include folks from TCM and other OEM reps as well as a number of engine builders. Not one person has ever contradicted anything we have presented. No one.

I guess no one can use an extra $1000us. It's truly a head-shaker.


Now, back to your regularly scheduled programming............

[Squawk7700]

I just fly with a Rotax. It has a throttle that I push in to make the engine noisier and then I go flying.... :)

.... and whilst flying your Rotax you are wasting up to 25% of your unleaded or Avgas fuel due to the lack of altitude compensation in your twin Bing carburetor set-up! With the simplicity, also comes a manufacturer built in nufty buffer which isn't your fault but it costing you money.

(Of course please ignore that if you are running a 912 IS model)

[The name is Porter]

I guess no one can use an extra $1000us. It's truly a head-shaker

Australians are tightarses Walter (if you've ever been tipped by one you'd know!) wait til they find that $1000 US is $1800 (or soon will be)

[FoolCoarsePitch]

Thanks so much for jumping on here to share that post Walter. Reading it put a smile on my face but the aftertaste from yet another realization how backwards we are down under was as bitter as usual.

[Tinstaafl]

Curiously, a 1980 PA31-325 I've been flying &/or managing since 2007 has a manufacturer POH that includes specific instructions on operating LOP. It even includes instructions on how to achieve LOP if temp limits are reached prior to LOP.

And that's using the original single point EGT. Not that I was comfortable with not knowing if every cylinder was sufficiently LOP, so the only time I ever did it was after I took over managing it to demonstrate to the owner the benefits of LOP and explain the need for an EDM to ensure *every* cylinder is sufficiently LOP. A few months later at its annual, one EDM fitted and LOP ever since.

BTW, that EDM made its purchase price back in a single year of operation in fuel saving. If you include install costs, then that first year still made good due to an injector line failure that year that the EDM helped me to decide to return to the maintenance base instead of landing at the nearest aerodrome - and then having to deal with remote maintenance & a stranded plane & pax.

[oggers]

I'm glad you've come along Walter. I believe your company came up with an excellent product at a time when it was needed and gave the engine manufacturers a timely shove.

Perhaps you can answer a question: do you believe it is possible to teach anybody in as little as 2 mins to safely operate a carbureted engine LOP; without limitation on altitude or power, and without engine monitor, using only seat in the pants feel for the "big mixture pull"? As claimed by your Australian colleague.

[no_one]

.... and whilst flying your Rotax you are wasting up to 25% of your unleaded or Avgas fuel due to the lack of altitude compensation in your twin Bing carburetor set-up! With the simplicity, also comes a manufacturer built in nufty buffer which isn't your fault but it costing you money.



Yes simplicity comes at a price, one that is probably worth paying given relatively small sums involved.

The Rotax carbs do have some altitude compensation but it is a primitive mechanical system. I sometimes wonder how rich or lean the engine really is.... and then I just go back to flying.

now back to the regular LOP debate.

[Walter Atkinson]

**do you believe it is possible to teach anybody in as little as 2 mins to safely operate a carbureted engine LOP; without limitation on altitude or power, and without engine monitor, using only seat in the pants feel for the "big mixture pull"? As claimed by your Australian colleague.**

Absolutely. I have done that on multiple occasions. (I taught my Aussie colleague!) It takes about 15 seconds if injected, 2 minutes if carbureted. How you might ask?

Carbed engines have notoriously poor F:A ratios and as a result many think it impossible to run them LOP. Not so. It is NOT imbalanced air--it is imbalanced fuel. The key is finding the optimal IAT using carb heat to get the fuel which has been atomized to become vaporized (I am hesitant to spend hours typing what can be demonstrated in under a minute in the airplane). Once this happens, the F:A ratios will be well balanced. I have accomplished this on radials as well as flat engines. I've personally accomplished this on most Cessnas, Pipers and many other carbed engines. Use the minimal carb heat to get the lowest DIFF number and you're good to go.

It only requires a single-probe EGT and a carb temp gauge.

It is important to appreciate that IF the F:A ratios are balanced all cylinders will be at very nearly the same mixture and the engine will run smoothly LOP. (And better ROP) This is how the engine is SUPPOSED to be. It does not matter how the fuel is delivered to the cylinders. Injected engines have this accomplished by having balanced nozzles (like GAMIjectors), while carbed engines use optimal vaporization to accomplish this. This is not my discovery. About 15 years ago, I read it in the small print (6pt. type footnote) of a 1935 engine operation manual; tried it on various carbed engines and found it to work quite nicely.

Consider this: If the engine is "conforming"--having balance F:A ratios, healthy ignition, no induction leaks and is being operated on the proper fuel--it will run smoothly across the entire mixture range, including LOP. Non-conforming engines will "seem" to run smoothly ROP because the differences in mixture, etc, between the cylinders is masked by the fact that the HP curve is so flat in the commonly useable range of ROP mixtures. Your Mark One calibrated butt doesn't feel the differences when ROP. It does when LOP.

SO..... if you run ROP, you need an engine monitor MUCH more than if you run LOP! If you have a conformity problem LOP, the engine will let you know by running rough. Not so if ROP.

WAIT! You did ask if ANYBODY could learn this in under 2 min.? Hm???????? I'd say "almost" anybody. They have to be willing to challenge what they know that isn't so. <g>

[Ultralights]

The Rotax carbs do have some altitude compensation but it is a primitive mechanical system. I sometimes wonder how rich or lean the engine really is.... and then I just go back to flying.


from my undersanding,( i could be wrong, more data on this would be good) the Rotax Bing carbys are good to maintain Mixture to about 9000 ft, ISA conditions, but the risks of damage from running high CHT,s from high internal pressures are reduced with higher RPM, and water cooled heads. Higher RPM actually lowers the internal cylinder pressures when running at the worst spot of about 50 deg ROP.

As for helping get correct air fuel ratio and vapourisation, the 912 ULS operating manual suggest the best carby air temp be kept at 21 deg C. (going from memory)

[extralite]

With full respect to Walter, would it not be more constructive to show Continental where their operating handbook is incorrect, rather than offering a $1000 reward to "hangar-flying-know-it-alls"? All things being equal, most pilots will gravitate to the information provided by the people that make the engine.

[Jabawocky]

The very first APS class that Andrew and I taught in was a HUGE class in Ada OK several years ago, one of the biggest ever. VIP students including senior TCM folk. They know already.

The problem is, changing a POH which is full of pearls of disaster is not something the airframe manufacturer's lawyers or anyone else wish to entertain. Mainly due to the cost, I assume.

:ok:

[Walter Atkinson]

extralite:

***
would it not be more constructive to show Continental where their operating handbook is incorrect
***

I could not agree with you more. You are exactly correct. (how come I never thought of that!! ;) just kidding...) We began doing that over 15 years ago. We met with a significant amount of resistance to them being willing to even look at the data. Over time, the OEMs have changed their position and are now coming around to agreeing with THEIR OWN data. (remember, "the physics are everywhere the same") One VP in a large aviation manufacturing company came to the APS class and began sending the people in his division in groups until most had taken the APS course. After trying to effect a change in the company over several years, he finally had enough and changed employment. Corporate inertia is a strong force.

Other OEMs continue to send their people to our course. We welcome them to the party. Several CASA people came to the APS class George and I taught in Sidney and there have been some changes in CASA's positions on some things. Whether or not that was a direct result of the APS class is uncertain, but the coincidence is compelling. There are many legal reasons that you will not see the POHs changed. Some new POHs are beginning to show an updated understanding.

Remember, Galileo (oops, that's a mistake, it was Bruno) was burned at the stake, but his facts remained true.

[Walter Atkinson]

BTW, I spent dozens of hours noting the scientific errors in one company's operating manual in an attempt to get the erroneous and downright dangerous recommendations corrected. We're not talking about "opinions." We're talking about math and science inaccuracies. One would think they would have appreciated someone trying to help them not to look foolish to their customers.

It pissed them off. Twelve years later, the same errors remain.

Go figure?

What's a fella to do?

[A Squared]

Remember, Galileo was burned at the stake, but his facts remained true.


Ummm, Galileo was not burned at the stake. He was censured by the Church and placed under house arrest ... a fairly loose house arrest. Claiming Galileo was burned at the stake in a statement about the immutability of facts might not communicate exactly what you're trying to say, if you know what I mean.

[Walter Atkinson]

Brain phart on my part! You are, of course, correct. Thank you for the correction. I was thinking of Giordano Bruno and typed Galileo! Silly me. The result is still the same. :ok:

***

FWIW:

Giordano Bruno, born Filippo Bruno, was an Italian Dominican friar, philosopher, mathematician, poet, and astrologer. He is celebrated for his cosmological theories, which went even further than the then novel Copernican model. He proposed that the stars were just distant suns surrounded by their own exoplanets and raised the possibility that these planets could even foster life of their own (a philosophical position known as cosmic pluralism). He also insisted that the universe is in fact infinite and could have no celestial body at its "center".

Beginning in 1593, Bruno was tried for heresy by the Roman Inquisition on charges including denial of several core Catholic doctrines (including Eternal Damnation, the Trinity, the divinity of Christ, the virginity of Mary, and Transubstantiation). Bruno's pantheism was also a matter of grave concern. The Inquisition found him guilty, and in 1600 he was burned at the stake in Rome's Campo de' Fiori.

[oggers]

Walter, thank you for the reply but I still have some questions:

Carbed engines have notoriously poor F:A ratios and as a result many think it impossible to run them LOP
Yes but do you believe it is safe to run LOP without any limits to power and without instrumentation? You said yes to that but then went on to specify two instruments that are required.

(I taught my Aussie colleague!)....The key is finding the optimal IAT using carb heat to get the fuel which has been atomized to become vaporized (I am hesitant to spend hours typing what can be demonstrated in under a minute in the airplane). Once this happens, the F:A ratios will be well balanced.

That is not the method jabawocky described. He didn't mention the use of carb heat or EGT gauge. But anyway I can see that carb heat would aid vaporisation. At the same time it seems to me that with a little bit of carb heat it would be a marginal gain as the fuel doesn't all vaporise at the same temp. But I've never tried this so I would like to see the data.

If you have a conformity problem LOP, the engine will let you know by running rough. Not so if ROP....Use the minimal carb heat to get the lowest DIFF number and you're good to go...It only requires a single-probe EGT and a carb temp gauge.

How do you know you have the lowest DIFF when using only single EGT? Applying carb heat will enrich the mixture. How can you be sure that the smooth running is a result of balanced flow rather than the enrichment, if you only have single point EGT and the feeling in your butt? After all, if I lean until the engine runs rough and then add back some fuel it will smooth out but I haven't balanced the fuel flow by doing that. If I apply carb heat I can get the same result. So how do I know the mixture is balanced?

[27/09]

How do you know you have the lowest DIFF when using only single EGT? I'd hazard a guess. The engine will run smoothest at the lowest DIFF at LOP.

[Walter Atkinson]

***
Yes but do you believe it is safe to run LOP without any limits to power and without instrumentation? You said yes to that but then went on to specify two instruments that are required.
***

It's less of a problem than running ROP without regard to power or instrumentation. We haven't seemed to mind doing that.

***
That is not the method jabawocky described. He didn't mention the use of carb heat or EGT gauge. But anyway I can see that carb heat would aid vaporisation. At the same time it seems to me that with a little bit of carb heat it would be a marginal gain as the fuel doesn't all vaporise at the same temp. But I've never tried this so I would like to see the data.
***

Well, I think he was talking about injected engines, and he didn't go into details, but I know that he knows. You do need some method to know where the mixture is set whether ROP or LOP. Why do we accept not knowing where the mixture is set when ROP and have a fit if we don't know it LOP? That's backwards. It's much more dangerous not knowing ROP, it's just that we've become comfortable not knowing because we didn't know what we didn't know.

The data will be compelling for you to observe.

***
How do you know you have the lowest DIFF when using only single EGT? Applying carb heat will enrich the mixture. How can you be sure that the smooth running is a result of balanced flow rather than the enrichment, if you only have single point EGT and the feeling in your butt? After all, if I lean until the engine runs rough and then add back some fuel it will smooth out but I haven't balanced the fuel flow by doing that. If I apply carb heat I can get the same result. So how do I know the mixture is balanced?
***

When one leans to roughness and enriches to smoothness one has NO idea where the mixture is set. It could be well ROP or well LOP or anywhere in between, depending on the balance of the F:A ratios. If one leans to roughness, then adds a bit of carb heat, the major effect is to vaporize the fuel, not richen the mixture, although both are happening. From that point do it again, and again, until no more carb heat smooths things out. That is where you will have balanced F:A ratios. This is crude without instrumentation and unless one has a very good handle on how this all works, may be difficult to achieve on the first effort. Instrumentation, even minimal, is a huge asset. One "can" fly needle, ball, and airspeed in instrument conditions, but having an AI, Altimeter, and DG is a BIG help! If you have a carb temp gauge (you do have one, don't you?) once you find the optimal temp, it works under all conditions.

This is one hell of a lot easier to demonstrate than type.

[Walter Atkinson]

***
I'd hazard a guess. The engine will run smoothest at the lowest DIFF at LOP.
***

Correct, and this is usually with a minimal degree of carb heat unless it is a very, low OAT. Additional carb heat from that point does not improve F:A balance and will reduce power.

Use the least carb heat required to get the lowest DIFF number. Once you find that carb temp, it works at all OATs.

I've accomplished this in numerous, different types of carbureted aircraft and it has worked in every, single one of them. I guess Sir Isaac Newton was right. "The physics are everywhere the same."

[extralite]

Thanks for the reply Walter.

Il be trying the LOP. Assuming we go 50 degrees LOP for the hottest cylinder, what would we expect the CHT to do? Intuitively i feel like it would heat up as we leaned off, but from this discussion it seems like it might also cool a little?

[Lead Balloon]

The curves that Jabba posts (which were produced by APS) provide the answer.

The CHT will be cooler at any mixture richer or leaner than around 50 degrees F rich of peak.

To put this another way, your CHT will be hottest at an EGT of around 50 degrees F rich of peak, and will get cooler whichever way you change the mixture.

It's counter intuitive, but your CHT will be cooler at peak EGT than at 50 degrees F rich of peak. Keep leaning from peak EGT and you're going LOP and the CHT is getting even cooler.

That's why the APS folks say that when running ROP, it's important to make sure the mixture is set far enough ROP.

[extralite]

Perhaps the reluctance to run lean is from what we have all learned from early on about engine. Running lean can cause knocking..pre-detonation and damage to valves.

How are leaded aero engines immune to this?

[Jabawocky]

Perhaps the reluctance to run lean is from what we have all learned from early on about engine.

Perhaps…..but what you learned was factually wrong. But learn it you did. That is why some folk have a hard time learning the truth.


Running lean when ROP(Not LOP)can cause knocking..

That is true in a way…..but let me clear things up in simple short statements.

1. On a conforming NA engine on conforming fuel, detonation is not possible.
2. On a turbo charged engine it is possible by misuse of the mixture knob to cause detonation, but only on the rich side of peak.
3. Detonation is what people call knock, but you can't hear it in a plane like you can a car.
4. Pre-ignition, usually (by far the most) caused by a spark plug ceramic being damaged. Occasionally by cross firing in magnetos and possible but rare by helical tangs being screwed in too far and exposed from the head. This damages pistons and really fast.
4(a) Spark plugs get damaged mostly by being dropped by mechanics. Some times but not often as a result of detonation shock waves.
5. Valve damage is hardly unlikely caused by detonation or even preignition. Burned valves are caused by machining errors at time of installation, the defects take time to appear, usually 600 hours +600/-200 and any mixture abuse is likely to speed up the process due heat and pressure, but the defect is there from the start and not pilot induced.

How are leaded aero engines immune to this?

I am not sure how to answer this? :uhoh: Maybe ask your question again in a different way?

Hope that helps.

Pb Ballon :ok: Whoever you are, I feel like you have been a good student of the science.

[Lead Balloon]

What does "running lean" mean? All mixtures that support combustion are somewhere on the lean curve.

And wouldn't the greatest risk of all those nasties (noting that pre-ignition and detonation are different things) be at the mixture setting that produces the greatest cylinder peak pressure and temperature? i.e at around 50 degrees F rich of peak?

When an engine starts running 'rough' when leaned, it is almost always because of the imbalance in F/A ratios going to each cylinder and the resultant imbalance in the power outputs of each cylinder. Nothing is 'misfiring' or detonating or pre-igniting or knocking.

[Jabawocky]

oggers
That is not the method jabawocky described. He didn't mention the use of carb heat or EGT gauge.

Sorry if I have confused you but I do not know what you are referring to?

I suspect it is where I was talking about an engine I know has no leaks, good induction and a carburettor…….and it nicely runs LOP? If that is the one it is an O320 powered RV6 with a FP prop, and it does have a single point EGT (which is almost useless by itself) but I know it runs nicely LOP, and the simple method is to lean for a 100 RPM drop. This is about 10-11% drop in power, or like the old days a 10% BMEP drop.

Let me know if that is not what you were thinking of. Happy to help explain otherwise. Or Walter will if I am not doing a good job of it. ;)

Not everyone will be as confident or have the understanding and feel for this, but many of the APS students will. Why is that you might be thinking?

The answer is what they see in the cockpit using whatever instrumentation they have, complete or very little, they can interoperate that info to reflect what they would have seen in class on a fully instrumented dyno. The human FADEC is a pretty powerful thing. :ok:

[oggers]

Sorry if I have confused you but I do not know what you are referring to?

Ok Jabawocky, so you said it is a "big mixture pull...quickly moving the mixture leaner. As soon as you feel the deceleration - stop." And you said the engine has to be 'conforming' to begin with. There was no mention of carb heat or an IAT gauge. Whereas Walter said:

The key is finding the optimal IAT using carb heat to get the fuel which has been atomized to become vaporized...Non-conforming engines will "seem" to run smoothly ROP...Your Mark One calibrated butt doesn't feel the differences when ROP. It does when LOP.

Walter starts with a 'non-conforming' engine and smooths it out with carb heat. Nothing about feeling the deceleration, only feeling for smoothness. He says you use EGT and IAT. You have described two different ways of setting up for LOP.

Also:

the simple method is to lean for a 100 RPM drop...Not everyone will be as confident or have the understanding and feel for this, but many of the APS students will. Why is that you might be thinking?

I don't think that leaning until you get a 100rpm drop is too difficult for the average pilot. Doing that from 100% power is the concern especially as Walter is now doing that with carb heat applied. I would like to see your data for doing this with a carb engine. Simply describing the priocess raises more questions than it answers.

[oggers]

Walter:

[LOP is] less of a problem than running ROP without regard to power or instrumentation. We haven't seemed to mind doing that.

The question was do you think it safe to run LOP without limitation to power. I don't agree that we 'haven't minded running ROP at full power'. The manufacturers have given us limtations for both LOP and ROP best power mixture. So we have minded. What we haven't minded is running full rich.

Well, I think he was talking about injected engines,

He specifically said "the Big Mixture Pull works every time. And yes that is a carby engine. "

The data will be compelling for you to observe.

No doubt. Please post this data for the carby engine.

If one leans to roughness, then adds a bit of carb heat, the major effect is to vaporize the fuel, not richen the mixture, although both are happening. From that point do it again, and again, until no more carb heat smooths things out. That is where you will have balanced F:A ratios.

Yes I get the concept. But it depends on how much fuel you actually vaporise versus how much heat you have to use. The data will clear this up I'm sure....

[Lead Balloon]

This is why there is a 2.5 day face-to-face course.

Reacting to ad hoc questions on a blog is not an efficient or effective way to teach people engine management. It is also unreasonable to expect someone to divert their personal time to answering every supplementary question that will almost invariably arise from a narrow explanation of the issues relevant to a specific set of circumstances.

If you think you're being scammed, oggers, just move on. Leave the credulous to the snake oil salesmen.

If you don't think you're being scammed, perhaps you should ask yourself whether it's reasonable to demand that you be given, free of charge, a complete, comprehensive, written answer, covering all the 'ifs' and 'buts' and exceptions, to every question you're inclined to ask.

Your closing sentence smells sarcastic and suggests feigned confusion.

The voluntary contributions of the APS folks on blogs often remind me of the old saying: "No kind act goes unpunished."

[Jabawocky]

Pb Ballon is correct
The voluntary contributions of the APS folks on blogs often remind me of the old saying: "No kind act goes unpunished." :ouch:

oggers, let me answer each one at a time.

1.The particular aircraft RV6/O320 I referred to is a conforming engine sans carbie heat. Don't know why and don't care either. On the odd occasion I crack the throttle off the WOT position, another technique that helps in some aircraft because it makes some turbulent flow. Non of what I said is contradicting what Walter said, some times you get lucky and some times you have to deploy all the tricks in the book. There is a PA24 in my hangar that has a multitude of issues of which I am working through, but so far the F/A ratio's are so poor even running full rich it is a nightmare. Yet the LAME's and engine builder have their head in the sand on it. I will win eventually even if all we do is get the ROP side of things wring right. There is no one size fits all with carby engines I am afraid.

2. I think you will find Walter was referring to the EMS visual verification by reference to the EGT values, it is fair to assume the slow leaning process used here will not yield any perceivable deceleration at all. If however a BMP is the way you do it, you will feel the deceleration and not see the EMS trends because it is done quickly. (You really do need to spend a weekend in class, Ada OK in a couple of weeks is your next chance).

3. Answres in red here;
I don't think that leaning until you get a 100rpm drop is too difficult for the average pilot. No it is not, but with a C/S prop it is so it is not a one size fits all deal hereDoing that from 100% power is the concern especially as Walter is now doing that with carb heat applied.Here again you show the need to do the course and understand the science. I will explain below but read Lead Ballons opening line about how easy it is to teach on a forum. I would like to see your data for doing this with a carb engine. Simply describing the priocess raises more questions than it answers. This is why we take hours of questions at breaks, lunch breaks, over dinner during a class weekend. If you do not understand from the class we try to explain it better for you during the break.

Detail on starting at 100% power and going LOP. :ok: Simply put when you do a BMP at any power setting you end up on the graph at the point around the most efficient or where best 1/BSFC peaks. So at 100%, scooting down the beach having a ball……the BMP achieves what the old radial airliners did with a 10% BMEP drop, if that is done in my aircraft with a CSU its stays at 2700, if its a FP it drops around 100 RPM, and you get around 88% power typically because unless the QNH is really high you never had 100% anyway even with the wheels in the water :}

At high powers you want to be around 80dF LOP (70-90 range these are rubbery figures and we do not split atoms here), and that will coincide with about the 10% or so power drop.

There is no problem doing this at all. None, Zip,Zilch….and the engine will run for thousands of hours like this happily. This is how your diesels and turbines run so why not your IO540. The CHTs will be 30-40dF lower and this confirms the ICP is lower than when full rich, what is not to like.

I don't have a 10' 2700 RPM photo, because that would be illegal here (wish I did) but I have done LOP take-offs at around 91% power, and the take off run for my plane becomes like a Bonanza, almost exactly and the CHT's are unbelievable good. Most GA planes need the extra ponies so it is not suggested for everyone else. But it proves the point well. What I do have is an old photo from when "morno" was flying and this is 1000' and 2400 RPM, and the power was about 80%. Enjoy!
http://i849.photobucket.com/albums/ab58/jaba430/photo2-3.jpg

Here is one in the cruise at 10,000' (new panel)
http://i849.photobucket.com/albums/ab58/jaba430/A100TAS17042LPH_zps3fcaaa71.jpg

And here is the concept graph, derived from real data, and all the answers to your questions can be found here. The two brown 1/BSFC curves represent a moderately high power, say 80-85% for the unbroken line and about 70-75% for the broken brown line. As the %age power reduces that brown line peaks a little further to the right. If it were 65% power or less it would peak in the -10 to -20 from peak region.
http://i849.photobucket.com/albums/ab58/jaba430/Landmarksgraph_zpsbfb07cbb.gif


If you want to see all the data…and there is tonnes of it, you need to either be in Ada OK in a few weeks, BNE Qld next year, or do the online class (good but no Q&A sessions with that!). Beyond that I think we have exhausted the forum concept.

If anyone else has questions please fire away. :ok:

[Walter Atkinson]

extralite:

***
Perhaps the reluctance to run lean is from what we have all learned from early on about engine. Running lean can cause knocking..pre-detonation and damage to valves.

How are leaded aero engines immune to this?
***

What we ACTUALLY learned (or should have learned) is that running "not rich enough" on the rich side was the cause of the above issues. Running not rich enough does result in high CHTs and high ICPs. It does NOT cause knocking, pre-ignition or damage to the vales, per se, but it does put the engine at a higher risk for those things.

Aero engines are not immune to any of the problems of gasoline, piston engines. It's just that while the observations may be accurate, the assignment of causality is flawed.

[Lead Balloon]

FFS. It's because no one's invented a perpetual motion machine yet. :ugh:

Ya can't save increasingly massive amounts of fuel and go increasingly faster. Get it?

[Walter Atkinson]

It's easy to know your power output when LOP. If you have an 8.5:1 compression ratio, simply multiply 14.9 x FF in gph = HP output. Other CRs have different multipliers. For example, the TC engines with 13.75:1 CRs, have a multiplier of 13.75.

ROP power output is a little more complicated to calculate and the POH numbers are usually generalizations, not actual numbers.

I can promise you that the laws of physics will insist that 70% power ROP and 70% power LOP WILL produce the same TAS. BTDT thousands of times.

As for taking longer when slower, well, sure, but the 25% fuel savings offset the 3% loss in TAS quite nicely. If you need to get there 3% faster, you'd better not accept single vector from ATC. :=

[Jabawocky]

CTRE

What aircraft do you fly and how do you fly it now? What speeds do you get? With this we can talk in real terms for your application.

Happy to do the mental maths to help you out. What I suspect is that if you lose way too much speed you are simply flying too far LOP. This is not uncommon. I can help you with this if you would like to detail what you have and how you are doing it.

This could make for an educational example for others watching.

:ok:

[Lead Balloon]

"160 LOP" cleared? 160?

As others have said, 70% power ROP is 70% power LOP. But here's the constraint if you're running a normally aspirated engine: You can't "add" manifold pressure if you're already at wide open throttle. (That's why the turbo-normalised engines are so popular.)

For my part, I'm happy to save about 15 litres an hour in return for about 6 knots TAS.

I fly lots of long legs. To make the maths simple, let's assume it takes me 15 minutes to climb to 8,500', after which I've 450 nms to go. Again to make the maths simple, let's assume it's nil wind and the GS will remain the same in the descent.

I'm going to use the same engine management technique to get to 8,500', irrespective of whether I'm going to choose subsequently to cruise LOP, ROP or at peak. So we can ignore the climb consumption and GS.

450 nms at 160 = 2.8 hours X 60 litres per hour = 168 litres

450 nms at 150 = 3.0 hours X 45 = 135 litres.

I'm happy to spend 12 minutes to save 33 litres. (In reality, flight after flight, the TAS sacrifice isn't as high as 10 knots and the fuel flow difference is greater than 15 litres per hour.)

Obviously there's not much of a difference if all you do is flog around in the circuit or go for 2 hour jollies for the hamburger on a Sunday.

But there's a key point that must be understood here, because it points up why some people get wider TAS differences and narrower fuel flow changes. When I run ROP, I run sufficiently ROP. That means I'm way cooler than 50 degrees F ROP if I'm running ROP.

If, instead, I were in the habit of setting my mixture to 50 degrees F ROP, I would save only about 10 litres per hour and lose about 15 knots' TAS running LOP (I'm rounding here). But I don't like flogging my engine to death at 50 degrees F ROP. So if you want to compare FF and TAS apples with apples, you have to compare sufficient ROP with sufficient LOP.

[Walter Atkinson]

At normal cruise altitudes, the difference between the Best Power mixture (80dF ROP), and best economy (BSFC(min) which changes with power) is about 3gph for a 3 knot speed loss. We've tested this thousands of times. It's always very close to those numbers. If you are losing more than 3-4 knots TAS, the mixture is leaner than optimal. It's not hurting anything to do so, because all that is happening is a loss of performance.

So, as Lead Ballon has pointed out, that's about 25% fuel savings (with a much happier engine) for a 5% speed loss. What's not to like?

[andrewr]

Burned valves are caused by machining errors at time of installation, the defects take time to appear, usually 600 hours +600/-200 and any mixture abuse is likely to speed up the process due heat and pressure, but the defect is there from the start and not pilot induced.

What evidence do you have for this? You would have to carefully inspect valves prior to installation and run hundreds of engines to prove that no valves without machining errors burned.

Or perhaps if you inspected every burned valve and found pre-existing machining errors in all.

I doubt that either has been done. This is the sort of blanket statement that turned me from a LOP believer 10 years ago when I first read John Deakin's columns to an APS sceptic now.

[Ultralights]

i have heard this argument quite a few times, "running LOP burns valves!" yet how can a temperature, thats exactly the same if on the Rich side of peak, cause burnt valves, when the same temp on the rich side wont?

peak is peak, it can go no higher! (thats why its the peak)
so 50 deg lower on the RICH side is exactly the same as 50 deg lower on the lean side.. so it cant be temperatures on the lean side that cause burnt valves.

[Jabawocky]

Andrewr …….Is that all it took? :confused:

If you ask a few of the leading engine builders around who actually know their stuff, and I am not one of them, the likes of Andrew Denyer, David Paynter, Bill Cunningham, the Barret's you will find the truth.

They find the exact same failures in ROP run cylinders, so how could it be LOP ops? They also comment on the deposits not helping and may in fact be accelerating guide wear.

I hope you can restore your faith in science and data now.

I am sure Walter can add to this if he reads this.

[Aussie Bob]

Andrew, I can give you anecdotal evidence. I had a O300 rebuilt and balanced with all new cylinders fitted. This engine would not run rough when it was leaned out, it would simply loose power. When I had favourible conditions I would often see fuel flows around 26 litres per hour with the throttle wide open. Within 250 hours, all cylinders had been off due to leaking exhaust valves. Some were fixed under warrantee, some were fixed by a shop that specialised in vintage motorcycle repairs. (Taken there by my LAME)

I did not change the way this engine was operated and went on to do aother 600 odd trouble free hours in it. The new owner, who I keep in contact with, has had no issues either. Apart from the valve issues this has been an exceptional engine.

All evidence thus would tend to point at poor cylinder manufacturing.

[andrewr]

50 deg lower on the RICH side is exactly the same as 50 deg lower on the lean side

Ah, but is it? Remember what EGT is measuring - the temperature of a probe inserted at some point down the exhaust pipe. It is at best measuring the average EGT at that point.

I would expect that if damage to valve sealing surfaces occurs, it would be most influenced by the gas temperature at the instant the valve begins to open and the temperature of the first perhaps <1% of gas to exit. The average gas temperature in the exhaust is not necessarily indicative.

Measurements I would be interested to see:
- Instantaneous EGT in the exhaust port through the combustion cycle vs measured EGT as the mixture changes
- Temperature of the valve head vs EGT as the mixture changes

[Lead Balloon]

Let me get this straight, Andrew

If someone makes the blanket statement that running LOP causes burnt valves, that's OK.

If someone makes the blanket statement that manufacturing defects cause burnt valves, that's not OK.

If you wish to ignore the science and data that prove that ROP is where you can give your engine the hardest beating you can give it, go forth and give it that beating. If your engine happens not to suffer burnt valves or other problems, you can tell yourself that it's because you don't run LOP.

Funny thing too is that the burnt valve problem is confined almost exclusively to CMI engines and not Lycomings. Clearly nothing to do with manufacture and everything to do with LOP?

Ignorance is indeed bliss.

The alternative is to register on a blog like BeechTalk, and do some research about what's happening in a first world GA country. The poor quality control of CMI cylinder manufacture is widely understood and discussed in detail, and the SOP of people considering cylinder replacement is to send the replacement to a competent engine maintenance organisation first, to get the valves installed properly. Those people are not doing that for fun or because their astrologer advised them to.

[Aussie Bob]

The alternative is to register on a blog like BeechTalk, and do some research about what's happening in a first world GA country. The poor quality control of CMI cylinder manufacture is widely understood and discussed in detail, and the SOP of people considering cylinder replacement is to send the replacement to a competent engine maintenance organisation first, to get the valves installed properly. Those people are not doing that for fun or because their astrologer advised them to.

And how I wish I had done just that with my old O300. The pain of pulling cylinders between and during annual inspections is not something I wish to repeat.

[andrewr]

If someone makes the blanket statement that running LOP causes burnt valves, that's OK.

If someone makes the blanket statement that manufacturing defects cause burnt valves, that's not OK.

I'm quite happy with the statement that either MIGHT cause burnt valves but would be looking for evidence for both. It seems quite likely to me that there can be more than one cause.

The statement that LOP does not cause burnt valves, and burnt valves are caused by manufacturing defects is more definite and I would be looking for evidence to support it.

Incidentally, I found a flight engineer's notes on operating the Pratt & Whitney R-4360 (one of APS's beloved radials):

R-4360Ops1 (http://www.enginehistory.org/r-4360ops1.shtml)

From those notes, when leaned at cruise power the ignition timing was advanced from 20 to 30 degrees which favored longer valve life.

Also, ignition timing advance maintained peak pressure at the most effective point as the mixture was leaned. Why then do APS say that it is a good thing to delay the peak pressure at cruise power (which is the same effect as retarded ignition timing)?

Everybody else I can find (including R-4360 operations) say that you want to advance the timing at cruise power compared to maximum power. APS want to effectively retard it...

Another thing arising from that document - APS tell us over and over that your Lycoming is effectively the same as a big radial. In this case it's obviously not - if you can't advance the ignition when LOP, that is a significant difference.

[andrewr]

450 nms at 160 = 2.8 hours X 60 litres per hour = 168 litres
450 nms at 150 = 3.0 hours X 45 = 135 litres.

160 vs 150 knots should require about 20-25% more power.

How much fuel do you save? Are you sure that it is more than if you just reduced the throttle/rpm until you were at 150 knots while operating according to the engine manual?

[Lead Balloon]

My primary reason for running LOP is not to save the fuel, although that's a pleasant bonus. (The rounded fuel savings calcs are in my post, confirmed by many hundreds of hours of real world ops.)

My primary reason for running LOP is to save the engine.

I don't particularly care what the engine manual and POH say about settings. The engine and prop are rated to run at 2,700 and full power continuously, so I know that anything less than that isn't going to be prohibited. (There are no RPM range limitations.)

What I do know is the CHT for each cylinder, the EGT for each cylinder, the FF and TAS, +/- not much, at each point on the lean curve. I therefore know where on that curve I could give the engine the hardest beating I could give it, and when I'm not at that point.

There is no point in playing with MP of a normally aspirated injected engine like mine, unless I'm in the circuit or doing some low and slow sightseeing. I set wide open throttle at the start of the take off run and don't touch it again until joining the circuit at my destination. I'm a simple person and don't like unnecessary complications.

[haydnc]

If anyone else has questions please fire away.

Yes Jabba,

I want to know how you're getting 170 kt TAS at 10k LOP when 'book' figure should be closer to 160kt ROP.

..And why I only get about 154kt LOP on the -7!

Haydn

[Lead Balloon]

PS: Andrew, it's worth reviewing and marking the signifance of the brown curves in that set of curves that Jabba frequently posts.

[Jabawocky]

HC
Yes Jabba,

I want to know how you're getting 170 kt TAS at 10k LOP when 'book' figure should be closer to 160kt ROP.

That was well spotted. As you can see there was a fair amount of westerly wind, and some wave surfing going on. It would have been about TAS164 just prior to that. Don't get too upset by that. ;)

[andrewr]

it's worth reviewing and marking the signifance of the brown curves in that set of curves that Jabba frequently posts.

I have seen and understand the charts, but it's hard to estimate the significance when there is no scale. I see the theoretical increase in efficiency but without a scale you can't tell whether it's 10%, 1% or 0.1%.

All I know is that people keep posting their "fuel savings" from running LOP, and when you do the calculation it's no better than what you would expect from the speed reduction.

Here's the test we need to see:
Set your LOP 150 knot cruise and note the fuel flow.
Then set the recommended best economy setting and adjust the throttle for the same 150 knots (same rpm). How much does the fuel flow differ?

I know, this gives the highest temperatures and pressures etc...

BUT:

Temperature and pressure is what turns the prop around so it's not surprising that you get the best economy where temperatures and pressures are maximized for a particular fuel flow.

The important question is whether they are temperatures and pressures that the engine is designed to handle. If you are well below the temperature limits, and well below full power, temperatures and pressures should not be an issue.

[Jabawocky]

Andrewr

I demonstrated this just recently, and these numbers are from memory as I did not video it, but here we go;

We were at something like 2500' and maybe 2450-2500 RPM and around 75% power LOP at 49LPH (about 40dF LOP). I then went full rich, and adjusted the MP to get me the same %age power which would have been around 24" and set appropriately 180 or so ROP, which ironically on a well set up Bendix fuel servo was on the full rich stopper or a bee's whisker off it.

Hey presto, same power, same speed, and a whopping (from memory OK) 70-75 LPH, and if I am wrong it was not far from it.

Now that is massive you say. Yep sure is and the higher the power the bigger the fuel spread because you need more so much more fuel to achieve the same peak pressures or at least keep them down.

You need to see this on the Carl Goulet Memorial Dyno test stand to fully appreciate this. No other way to describe it.

Now if we get to say higher altitudes and compare 65% and we are 100-125dF ROP and say 10dF LOP, the percentage of extra fuel is not so massive, for example on a IO520 that might be 47LPH compared to 58LPH. On my IO540 that is 41-42LPH to 53-54LPH (off the top of my head).

I think this is worth repeating, and Walter will no doubt agree……….You need to see this on the Carl Goulet Memorial Dyno test stand to fully appreciate this. No other way to describe it.

[Lead Balloon]

So Andrew, your view is that provided the higher CHTs are under redline, it's OK. You are of course free to choose to operate engines that way (but you'll never get to touch mine).

For my part, I choose to operate my engine where it is put under the least stress to achieve the performance I need. I don't need scales on those curves to know where those settings are, because the data out of my engine monitor over many hundreds of hours (and many thousands of other monitors over millions of hours) and actual TAS and fuel consumed are objective facts.

I still reflect on that poor kid PIC and his pax on the Whyalla Airlines Chieftain. I still wonder whether the engine failures might have been avoided if the mixture had been left sufficiently rich of peak rather than leaning it to a mixture rich of peak that meant the engines were given around about the hardest pounding they could be given. (CHTs still under redline, mind you Andrew. Just before they got very cold.)

[IFEZ]

There's been a lot of discussion on here about the merits of running LOP and ROP to varying degrees but I'm interested to know what you guys think about doing neither ie running at peak EGT? I notice in the POH for the PA-32R-300 which has an IO-540 engine, the performance charts for economy cruise, range and endurance, are all based on 'mixture leaned to peak egt'. The performance cruise chart says to use 'mixture leaned to 100deg rich of peak EGT at 75% power and below'.

These are based on standard issue ex factory Lance with single probe EGT.

Any comments on the merits of these performance charts..? All I've ever heard of is leaning to peak EGT, then either leaning further to LOP or leaning less to ROP but never staying at peak EGT.

[Walter Atkinson]

This thread is full of misinformation.

**Ah, but is it? Remember what EGT is measuring - the temperature of a probe inserted at some point down the exhaust pipe. It is at best measuring the average EGT at that point.***

It is NOT measuring the average EGT. It is measuring the EGT minus the refractory period cooling between pulses of hot air.

***I would expect that if damage to valve sealing surfaces occurs, it would be most influenced by the gas temperature at the instant the valve begins to open and the temperature of the first perhaps <1% of gas to exit. ***

That is proven to be false. EGT does NOT affect valve temperature. We have hard data to prove that. The data came from a 1943 top secret NACA report done during WWII.

***Measurements I would be interested to see:
- Instantaneous EGT in the exhaust port through the combustion cycle vs measured EGT as the mixture changes
- Temperature of the valve head vs EGT as the mixture changes***

Both of those are available. The first answer is that the two temperatures track rather closely--as in immeasurably different in delta

The second is that valve temperature does NOT track EGT. This is 1943 data, not ours. Lycoming verified it in 1966. We ran the test confirming this about 15 years ago. Funny how the physics is everywhere the same. The hottest valve temperature is found with a mixture of 40dF ROP. As the EGT is going up toward peak, the valve temperature is getting cooler. Anyone who suggests that EGT affects valve temperature must reconcile this fact. In addition, there are times when the exhaust gasses blasting past the valve are actually cooling the valve. These were surprises we learned while MEASURING these things.

BTW, EGT is not a measure of the temperature of combustion. It is the result of the expansion of the 3800dF combustion temperature. That's why low compression engines have higher EGTs and higher compression engines have lower EGTs.

[Walter Atkinson]

***Also, ignition timing advance maintained peak pressure at the most effective point as the mixture was leaned. Why then do APS say that it is a good thing to delay the peak pressure at cruise power (which is the same effect as retarded ignition timing)?***

Because the fixed timing is "averaged" in our flat engines to be "acceptable" across the mixture spectrum. The R-4350, along with some other radials had the timing retarded at max power to control ICPs and CHTs, and more importantly to stay barely outside the detonation margin. This retarded takeoff timing at max power was unacceptably retarded at cruise powers, so they had a way to alter timing to make it work efficiently in both high-power and cruise-power configurations.

One must be careful in comparing these engines and their engineering requirements to our GA engines.

The effective timing on our engines is too far forward at high powers ROP and slightly retarded when in cruise. If we retarded the timing during takeoff, the engine would produce more power and the CHTs would run lower, but if we did that, the timing would be so far retarded in cruise as to be very inefficient. It's a trade-off. We do not advocate delaying the peak pressure beyond 16dATDC. That is optimal.

'Tis amazing how often one gets misquoted by internet experts.

[Walter Atkinson]

***Temperature and pressure is what turns the prop around***

That is an over-simplified and basically incorrect statement. I can demonstrate many instances where a lower combustion temperature and a lower peak pressure produces more power than higher temps and pressures.

There are two enemies of metal: heat and pressure. It's good to control them.

Mean cylinder pressure relates to HP.

Peak cylinder pressure relates to longevity.

It is quite possible to have extremely high pressures with very little to zero power being produced. ??pre-ignition??

[Walter Atkinson]

The Lycoming recommendation to be 100dF ROP at powers above 75% is suboptimal. One should be richer than that if longevity and engine health are your goals.

The Lycoming recommendation to run AT peak EGT for economy cruise is based on two facts: 1) that their engines' F:A balance is not good enough to run smoothly LOP, and 2) the difference in efficiency between peak and BSFC(min) is relatively, but measurably small. This recommendation was made for one purpose... to keep the customer service phone from ringing off the hook when their engine ran rough LOP.

Gentlemen:
There is a lot of misunderstanding and misinformation being posted in this thread. While there are certainly others who understand this well, the posts by Lead Ballon and Jabber are the posts with accurate information that can be supported by documented, repeatable, hard data.

DO NOT believe me, Lead Ballon, Jabber or any one else. Believe the Data. We have seen the data and have drawn conclusions based on that, not what we or anyone else might "think" to be right.

'Tis important to consider that without data, all you are is another person with an unsupported opinion.

[A Squared]

160 vs 150 knots should require about 20-25% more power.

How much fuel do you save? Are you sure that it is more than if you just reduced the throttle/rpm until you were at 150 knots while operating according to the engine manual?


I have seen and understand the charts, but it's hard to estimate the significance when there is no scale. I see the theoretical increase in efficiency but without a scale you can't tell whether it's 10%, 1% or 0.1%.

All I know is that people keep posting their "fuel savings" from running LOP, and when you do the calculation it's no better than what you would expect from the speed reduction.

Here's the test we need to see:
Set your LOP 150 knot cruise and note the fuel flow.
Then set the recommended best economy setting and adjust the throttle for the same 150 knots (same rpm). How much does the fuel flow differ?


Look, it's not a difficult concept. Start with the understanding that all else being equal, power varies with mixture, and that there exists some optimum mixture where power is at a maximum. It seems a pretty simple concept that for a given desired power output there must also exist two points, on the rich and lean side of the peak, where power is equal to that desired output. and for those two mixture stetting which yield equal power output, the cruise airspeed will be the same. And if the airspeed is the same, and one setting has lower fuel flow, then the fuel burned per mile is going to be less. I'm not sure which part of this you can't get your mind wrapped around.

[ShyTorque]

From those notes, when leaned at cruise power the ignition timing was advanced from 20 to 30 degrees which favored longer valve life.

Probably because by advancing the timing, the mixture is more completely burnt before the exhaust valve opens. Leaning the mixture slows down the burn, provided that detonation doesn't occur. Advancing the timing point compensates for that slowing. An open exhaust valve is subjected to greater temperature rise than when closed; A) because both sides of an open valve are exposed to the heat of the burning mixture and B) the edge of a closed valve valve dissipates heat through its metal seat.

[Jabawocky]

Shy Torque

Probably? Well it might seem to make sense, but it does not work as described. The best suggestion I have is read carefully what Walter wrote above. :ok:

[oggers]

Lead Balloon

This is why there is a 2.5 day face-to-face course.

Reacting to ad hoc questions on a blog is not an efficient or effective way to teach people engine management. It is also unreasonable to expect someone to divert their personal time to answering every supplementary question that will almost invariably arise from a narrow explanation of the issues relevant to a specific set of circumstances.

If you think you're being scammed, oggers, just move on. Leave the credulous to the snake oil salesmen.

If you don't think you're being scammed, perhaps you should ask yourself whether it's reasonable to demand that you be given, free of charge, a complete, comprehensive, written answer, covering all the 'ifs' and 'buts' and exceptions, to every question you're inclined to ask.

If you think you're being scammed, oggers, just move on. Leave the credulous to the snake oil salesmen.

Scammed? A little defensive there I think LB. I have asked for clarity and data. This is a public forum and so it is completely fair for advice being offered here to be scrutinised here. Of course if you don't like that, too bad. You can always take your own advice to "move on". But I am here to stay :ok:

[Walter Atkinson]

I have asked for clarity and data.
And, I have responded in an attempt to clarify and have provided some data. An internet forum precludes the presentation of very much data because of the bandwidth alone. I have presented over 16 hours of data dozens of times over 16 years and not one of the thousands who have looked at that data have questioned the accuracy of it. Anyone may chose whether or not they wish to take advantage of the opportunity to see and study that data, but to demand that it be provided free and at their whim seems a bit unreasonable.

[rutan around]

Oggers
Don't you take any notice of that nasty LB. Someone still loves you. Donald Trump loves poorly educated people. He said so on national TV.

[Ultralights]

you mean Donald Drumpf?

[rutan around]

Little Donald has done very well for someone brought up in poverty in a poor family without a billion $ to their name. How many of you could be where he is today if you were only left a lousy $44million to start your investment career?

[Cuban Eight]

EAA Video Player - Your Source for Aviation Videos (http://eaavideo.org/video.aspx?v=2274677932001)

Can the ppruners tell me if this man speaks truths?

He also tells us to go to APS.

[Walter Atkinson]

Start with the understanding that all else being equal, power varies with mixture, and that there exists some optimum mixture where power is at a maximum.
Hm? That's not quite correct.

When ROP, power is determined by mass airflow. FF has little effect in the normally used ROP mixtures. Once they get overly rich, yes, power decreases.

When LOP, power is directly related to FF. Mass airflow plays no part.

The reason there is a Best Power mixture has nothing to do with FF. It is the mixture where the mass airflow is adequate to burn all of the fuel. That does NOT occur at stoichiometric (AKA, Peak EGT). It occurs at approximately 75-80dF ROP.

[Walter Atkinson]

EAA Video Player - Your Source for Aviation Videos (http://eaavideo.org/video.aspx?v=2274677932001)

Can the ppruners tell me if this man speaks truths?

He also tells us to go to APS.
Mike has a lot of it right. He's been to the APS class three times and refined a lot of his knowledge thereunto, appertaining. He is honest in acknowledging APS and we appreciate his recommendation.

Where we disagree with Mike is on his recommendation to lean based on CHT. This is a very flawed concept. In addition, we do not think his approach to maintenance is optimal where dispatchability is concerned. Other than those two issues and few minor peccadilloes, he's got a lot of good information.

[A Squared]

Hm? That's not quite correct.

When ROP, power is determined by mass airflow. FF has little effect in the normally used ROP mixtures. Once they get overly rich, yes, power decreases.

When LOP, power is directly related to FF. Mass airflow plays no part.

The reason there is a Best Power mixture has nothing to do with FF. It is the mixture where the mass airflow is adequate to burn all of the fuel. That does NOT occur at stoichiometric (AKA, Peak EGT). It occurs at approximately 75-80dF ROP.

You're the only one talking about fuel flow. Yes, mixture ratio and fuel-flow are pretty tightly correlated, but you're interjecting words I didn't use.

Here's what *I* meant: If you had a power meter on your engine*, and you started with the throttle set and the mixture at full rich, then you started gradually pulling the mixture toward lean, you would see the indication on your power meter rise, peak, then fall as the mixture control moved toward Idle Cut Off.

I'm not sure what you mean about power not being a function of fuel flow exactly, and I'm not saying that you're wrong, but I think you may be making a semantic distinction that's not relevant to my statement.



* I flew for a number of years in an airplane which had power meters on the engines. For a constant RPM, a torque meter is a power meter. I have watched the needles rise then fall many, many times.

[Cloudee]

Lycoming say leaning on the ground is a no no in this flyer. What do the APS guys think of their logic?

Lycoming Flyer (http://www.lycomingflyer.com/november2015)

[KittyKatKaper]

That Lycoming advice has eff all to do with the actual powerplant., it is simply trying to stop one from taking-off with a leaned mixture.
And as for cooling the engine with full-rich during the taxi., who the bleep actually needs to operate an engine at high power, for prolonged periods, at low ground speeds. ? (LAMEs excluded)

[Jabawocky]

A2

You are correct in your statement about the small variation on the rich side of the peak where there is a rise in HP peaking at around 75-80 ROP. And yes when very rich it falls off a touch as the mixture moves ThetaPP out a fair bit.

You will no doubt appreciate in practical terms for the pilot in flight, splitting atoms is not relevant, and the small difference <1~1.5% is not a practical thing for pilots to be contemplating. We teach the whole thing in class but for practical application purposes what Walter describes is correct.


Cloudee,

Let me copy paste and highlight the OWT's, the BS and the spin produced by Lycoming to cover their butts from "loss of face".

To Lean or Not to Lean While You Taxi
Aviation is full of tribal knowledge from pilots, both past and present. One trick that often comes up, usually in the early part of your flying career is, “you should lean the engine while on the ground to prevent spark plugs from lead fouling.” In theory, this seems like a completely logical method. Less fuel equals less lead deposits in my spark plugs. So why do Lycoming Engines’ Operators Manuals recommend different?

Is there a better way? Not surprisingly, Mother Nature throws more unexpected factors into the situation, and while you might feel better trying, you can’t fool Mother Nature. No you can't and when operating as per Lycoming I always had far more Pb deposits, who are they trying to kid here?

WHY SHOULDN'T I LEAN DURING TAXI?
To start, Lycoming Engines’ Operators Manuals clearly instruct the pilot to keep the mixture at full rich during ground operations and engine run-up. By leaning on the ground, you may not entirely eliminate the problem of spark plug fouling. While you’re introducing less lead into the system, you are also reducing the cooling effects of the fuel. COMPLETE BS, at any power the combustion curves applyYour airplane’s cooling package is not designed for prolonged periods of zero airspeed operations. Of course, we have the propeller wash, but it isn’t the same as having airspeed blowing over your air cooled Lycoming Engine. Leaving the mixture rich helps cool your engine since you don’t have that airspeed yet. Supporting a myth by telling the truth…clever trick :=

Taxi and take-off can be a busy time for a pilot, especially if you are at a busy airport. Imagine you are at a complicated international airport. You’ve leaned your mixture to try to prevent the engine from fouling up. The tower is yelling at everyone, (Really??)making things stressful. There are jets all around you with engines big enough to suck up your entire airplane. (Sounds like a Greenpeace or PETA commercial- Are you scared yet?) You are given a challenging departure procedure and you are trying to brief yourself. Before you know it they give you a clearance to take-off-- not in 2 seconds, but right now. You start your take-off roll and realize the engine seems weaker than normal. Maybe it’s even got a little vibration to it. But you are committed now, and you’re running out of runway. Because of the heavy workload, you may have forgotten to push the mixture back to full rich, and it is negatively affecting the engine’s power for takeoff and climb. This happens more than you might think. (Only if they are poorly trained, Line up and go in a LYCOMING is simple, boost pump on mixture rich and GO!!!!Add to this that Lycoming’s Service Instruction 1094 recommends take-off be conducted at the full rich setting when at density altitudes below 5,000 feet; above 5,000 feet density altitude may require some leaning to achieve acceptable power and smooth operation. Complete myths designed to scare you. The APS method does everything it should and nothing it shouldn't. Do it right and the engine will stumble and almost quit…..you will push the red knob in GUARANTEED

WELL THEN, WHAT SHOULD I DO?

Make sure your mechanic is doing all of the proper spark plug maintenance. Lycoming Engines recommends spark plugs by part number in our Service Instruction 1042. It may be a good idea to check your plugs to make sure previous owners or mechanics installed the correct part numbers. Also, the spark plugs should be cleaned, gapped, and rotated at least every 100 hours of operation. If you are operating Champion spark plugs, information on those procedures can be found on their website here: Aviation Service Manual.
Ensure that your carburetor or fuel injection servo have the idle settings correctly adjusted. A proper idle set up will help reduce the possibility of lead collecting in the cylinders and spark plugs.
Your mechanic should run the aircraft until the engine oil temperature is up to the normal operating temperature before making any of the following adjustments:
Idle Speed - Increase the throttle to roughly 1,700 RPM and rapidly reduce it back to idle. Generally the airframe manuals recommend the idle speed be set between 600 RPM and 700 RPM. If it is outside the specification, it should be adjusted using the idle stop screw.
Idle Mixture - While at idle, slowly pull the mixture lever back to idle cut-off. You should notice a slight rise in engine RPM before it shuts off. Lycoming Engines recommends a rise of 10-25 RPM. If there is no rise, the engine is too lean and needs to be richened slightly. If it rises more, the engine is getting too much fuel and needs to be leaned.ALL GOOD ADVICE

4. Study the figure to the left. Lead fouling is greatly affected by the temperature of the gasses inside the cylinder. How can we take advantage of this? Shortly after you start your engine and have positive oil pressure, increase your throttle setting to obtain an engine speed between 1,000 RPM and 1,200 RPM. This will allow enough heat to be generated to properly scavenge lead from the cylinders. Anything less and the temperatures inside the cylinder will cool enough to form lead and carbon deposits, even if the engine is leaned. 1000 RPM is enough, think noise and stone damage
5. Just prior to engine shut down, increase the throttle setting to about 1,800 RPM. Operate here for 15 to 20 seconds. Reduce the throttle back to 1,000 RPM to 1,200 RPM and immediately shut down the engine using the mixture control. This will ensure the engine gets properly scavenged of lead just before shut down. Bad idea, heat the engine up to achieve what? Make a lot of noise, rotating props are best not where people are around….and I never found doing or not doing this made any difference, nor do thousands of others.

FINAL THOUGHTS
Don’t be afraid to question procedures that aren’t found in the Pilot’s Operating Handbook (POH). Poor practices which then become bad habits may have been passed down from pilot to pilot for generations; leaning during ground operations is one example. Always refer to the aircraft’s POH for the approved practices or operation instructions. If someone recommends something different than the POH, ask them to provide approved data to allow you to operate the aircraft using their method. Don't be afraid to question your POH, much of what is written in them is not scientifically correct, is misleading or contradictory to the engineering data in the same manual……so Be a critical thinker. Just because it is a POH does not mean it is correct, approved BS is BS all the same.


:ok:

[Walter Atkinson]

***
If someone recommends something different than the POH, ask them to provide approved data to allow you to operate the aircraft using their method.
***

This from Lycoming?????

"allow you to operate..." That's ridiculous. The POH "allows you to operate" anywhere you choose, unless it's in the LIMITATIONS section. The rest is nothing more than a "recommendation."

No one on the face of this earth has offered more hard data to pilots, mechanics, and OEM representatives than the teachers at Advanced Pilot Seminars. "Approved data?" What the heck is that? Because the FAA has stamped it as "approved" has nothing to do with it's scientific validity.

Over a decade ago, I asked Lycoming to provide data to back up some of their statements. I'm still waiting. Nada, Nunca, NOTHING. Why would someone not show their supporting data--unless they don't have any. Some of Lycoming's recommendations don't even agree with their own published data. Go figure?

[Lead Balloon]

The content of that Lycoming document is a crack up. If I didn't know that many of our US brothers and sisters don't 'do irony' too well, I'd guess Lycoming had run a competition to see who could:

(1) use as many words as possible to state: "Make sure you set mixture to full rich before taking off (unless DA requires some leaning) and make sure you maintain your spark plugs properly", and

(2) squeeze in as much unsupported codswallop as possible.

Go to 1,800 RPM for 15 to 20 seconds to "ensure the engine gets properly scavenged of lead just before shut down." I'm hoping that's the product of comic genius rather than abject ignorance. :D:D:D

[Ultralights]

ensure the engine is probably scavenged of lead just before shut down do they mean the Lead Bromide thats the result of combustion? and is actually a salt, and far from being a lubricant as clamed in the past? or is it the Tetraethyl lead which might have come out of solution with Avgas and left deposites before its burned and turned into a lead oxide and a bromide? or is it the lead oxide deposits or just plain old lead?

how does running at a certain RPM buring the same leaded fuel scavange the lead byproducs of previous combustion using the same fuel, when chemicals added to the Tetraethyl lead compond are designed to scavange the lead before it can be deposited during combustion, turning into lead bromide so it passes out with the exhaust.. (which freezez at 370deg C, hence leaves the light grey residue in the exhaust pipe)

I wonder if its a co-incidence that car engines became far more reliable once the fuels they used stopped producing a corrosive carcenogenic compound of lead during combustion?

[Lead Balloon]

Whatever it is, just imagine how bad it will be if it's not properly scavenged before shutdown. :eek:

[Jabawocky]

What does this tell you……….. It is worth a few minutes to watch, even if you do not see the parallel.

Margaret Heffernan: Dare to disagree | TED Talk | TED.com (http://www.ted.com/talks/margaret_heffernan_dare_to_disagree#t-67583)

Thanks WA:ok:

[gerry111]

As usual, Margaret Heffernan makes a lot of very good sense.


(I believe always keeping a very open mind to be rather wise.)

I've been flying VFR GA with someone on PPRuNe for more than 30 years. I check just about everything that person does and have never been unprepared to question anything that I was doubtful or unhappy with. I suppose that's now known as good CRM.


The properly (IO520) engine monitored aircraft with Gami Injectors runs LOP in the cruise. I'm happy about that because it is logical to do so.

[gerry111]

Lead Balloon,


I've just received my latest container of post landing lead scavenging gizmos.


(Starting from AUD 299-00 each plus GST and P&P.)


PM me for details?

[rutan around]

Jabba
Your clip doesn't relate to aviation. My 21 year old 600hour instructor knew more about how to run big bore air cooled aircraft engines than all the data backed, test cell experienced experts in the world. I have to believe him because he had the flight manual written by the sales team to back him up so it must be right. Those people getting double TBO using data based information are just plain lucky and any day now their planes will plummet to the ground.:mad::mad:

[Lead Balloon]

I purchased a Turbo Encabulator to properly scavenge the lead from my engine, thanks Gerry. :ok:

I switch it on during the 5 minute period in which I 'cool' my turbo after each flight.

[Jabawocky]

You guys! http://www.beechtalk.com/forums/images/smilies/rofl02.gif

[gerry111]

"Those people getting double TBO using data based information are just plain lucky and any day now their planes will plummet to the ground."


Or perhaps worse into the sea, Rutan? I just so worry for that young family orbiting at 500' near Anna Bay that Dick has warned us of... :ok:

[Walter Atkinson]

Jabba
Your clip doesn't relate to aviation. My 21 year old 600hour instructor knew more about how to run big bore air cooled aircraft engines than all the data backed, test cell experienced experts in the world. I have to believe him because he had the flight manual written by the sales team to back him up so it must be right. Those people getting double TBO using data based information are just plain lucky and any day now their planes will plummet to the ground.:mad::mad:

OK, I'm ready to learn. What were his recommendations and does he have hard data to back it up? I'm serious. I'm ready to learn.

Or, is he just another person with an unsupported opinion.

As for the video Jabba posted, it does apply to aviation in a BIG way. Open data and information not being recognized for what it is, or how to use it, while the old-schooled among us hang on to the way they've always done things in the face of the data. If you don't see that, well, you're missing the point.

It is worth noting that "a delusion is holding to an unsupported belief in the face of hard data to the contrary."

Each must decide for themselves how they will approach knowledge.

[A Squared]

OK, I'm ready to learn. What were his recommendations and does he have hard data to back it up? I'm serious. I'm ready to learn.

Ummm, Walter ... I'm pretty sure that RutanAround was being ironic. You may have missed that. :ok:

[Ultralights]

Or perhaps worse into the sea
OMG! actual shock cooling!

[Walter Atkinson]

Ummm, Walter ... I'm pretty sure that RutanAround was being ironic. You may have missed that. :ok:

Guess so! Sorry, if that was the case.....

[rutan around]

Walter
A X A posted
. I'm pretty sure that RutanAround was being ironic He is correct and I'll risk outing myself here when I tell you that you and I have met and chatted at an Australian APS. I learned to fly in 72 ( well started then. I'm still learning) When I asked my instructor how leaning hurt the engine he said the excess oxygen rusted out exhausts. I asked how just a few molecules of oxygen could do that. He didn't know - it just did. Then I asked how come diesel trucks didn't burn out their exhausts because diesels always have an excess of oxygen in their exhausts. He said they must have different metal in their exhaust systems. He also said leaning even further caused rough running due to lean misfire.

Only in the 90s did I learn the real reasons for these problems and then at the APS the whole picture was explained with great clarity.
The reason for the sarcasm was that people who won't look at data or are too lazy to try and understand it really annoy me. When hard data contradicts what they were taught they appear to prefer the unsubstantiated information given to them by someone just parroting whatever they were taught.
My father in law and a good friend both died of stomach ulcers even though the cause and cure had been discovered by then. It took 20-25 years before the medical generally accepted the data. How many people died a miserable death because doctors were too stubborn or to lazy to to critically examine the new data as it became available?
How many aircraft engines life will be shortened because some pilots don't understand the data?

[Walter Atkinson]

Data from a TIO540

Will run 35-40F LOP smooth as silk, after that: vibes in undies.
That's pretty normal for NA engines. Why won't they run leaner? The fuel atomization and vaporization is not as good as in turbos that will run as far as 120dF LOP quite smoothly.


I like TIT around 1500.... I find it hard to believe running TIT 1600+ and significantly higher EGT's is going to increase my TBO from my Lycoming approved ROP.
The question is, "Why do you 'feel' that way?" EGT/TIT are not in any way related to engine longevity. The only issue is the exhaust plumbing or turbo, but both of those components can easily handle 1650dF all day long. It's only when EGT gets above about 1700-1750 that the metal of the exhaust plumbing begins to suffer. The turbo is designed to operate at 1650dF continuously.

The issues in longevity are two-fold: 1) controlling heat, and 2) controlling pressure. Both of these are moderated when LOP. The difference between heat and pressure at Best power and at 50dF LOP are significant. Very significant. Two engines, one ROP and one LOP AT THE SAME HP, will have the LOP engine running much cooler and under far less stress.

An optimal LOP setting (NA) results in a loss of only about 3 knots TAS for a savings of 3 gph in a 285-300 HP engine. That's a 20% fuel savings for a 2% loss of airspeed. If you are losing more speed than that, you are leaner than optimal. If you take one vector from ATC, you've eaten up that speed difference! Turbos are different. They can actually produce more HP LOP than ROP if one is controlling CHTs. That means that I can go faster on less fuel and have the engine operate under less stress.

It may be worthwhile to ask, "if Lycoming really felt that their 'approved' ROP methodology was best, why is their new FADEC-type engine set up to run LOP?"

There are well over 400 million flight hours of hard data which supports the above comments.

[Walter Atkinson]

Maybe increasing MP reduces TIT and EGT?
In certain circumstances, it can, but it won't be by much. Increasing MP results in higher combustion temps and a slightly faster flame front speed. The faster flame front results in an earlier thetaPP and lower EGT/TIT, but again, it's not much--might even be "not enough to notice" since the temperature of combustion went up slightly. Again, this is not related to engine longevity.

[A Squared]

That's pretty normal for NA engines. Why won't they run leaner? The fuel atomization and vaporization is not as good as in turbos that will run as far as 120dF LOP quite smoothly..

I don't think he *is* talking about a Normally aspirated engine though. Seems like he's speaking about a turbocharged engine.

[Lead Balloon]

If that $1,500 included labour, it means the part was worth about $100. If not, $150.

[Ultralights]

im pretty sure any exhaust system will handle any temp that is Peak (as in, its never going to get any hotter) EGT.. considering steel exhaust pipes can glow red hot four hours on end without failure..

[Walter Atkinson]

All of this talk about hotter EGTs/TITs during LOP ops is interesting. Where I went to school, 50dF ROP and 50dF LOP were the same temperature! The OEMs recommended 50dF ROP! But then, I did go to school in the Southern US. Maybe I'm missing something!

[Jabawocky]

CTRE

I am going to PM you my phone number, you really would LOVE to do the class, and would find that all the religious hype is actually easy to see as fact of science but that is almost impossible to convey here on a post.

I look forward to helping you out a bit. :ok:

[oggers]

Walter

Over a decade ago, I asked Lycoming to provide data to back up some of their statements. I'm still waiting. Nada, Nunca, NOTHING. Why would someone not show their supporting data--unless they don't have any.

...ironic then, that on the previous page of this thread you excused yourself from providing data with this:

Anyone may chose whether or not they wish to take advantage of the opportunity to see and study that data, but to demand that it be provided free and at their whim seems a bit unreasonable.

:ok:

[Jabawocky]

Oggers,

Sorry to burst your bubble, but if you search even here on pprune you will find somewhere Walter posting that he offered USD$1000 of his own cash for every piece of data that Lycoming had that disproved the data shown and collected from the GAMI/TAT dyno (and P&W, CW et al).

He put money where his mouth is. Still has the $$ ;)

You could do the same. :ok:

[Walter Atkinson]

I have only excused myself from providing the data on internet forums for ONE reason. Insufficient bandwidth. If you could explain to me how to post 16 hours of data presentation in a post on the forum, I'm all ears. In, literally, hundreds if not thousands of posts over 15 years, I have provided reams of data. BUT, as I said, I have no duty to provide anyone with a graduate level education for free. What I provide for free I do so because I want to help GA pilots improve their knowledge and safety.

[oggers]

I have only excused myself from providing the data on internet forums for ONE reason. Insufficient bandwidth.

Walter, engineers have been managing to compile and communicate the results of their tests since before the photocopier was even a thing. Every scientific paper is available online these days. We have broadband connections. You don't even have to reproduce the data because you can simply provide a link to wherever it is.

I have no duty to provide anyone with a graduate level education for free.

Respond or don't, we all participate freely here – no point complaining about it.

Moving on:

EGT does NOT affect valve temperature. We have hard data to prove that. The data came from a 1943 top secret NACA report done during WWII....valve temperature does NOT track EGT. This is 1943 data, not ours.

This is not correct. NACA-754 of 1943 shows clearly that valve temps track EGT. Figures 7a, b, and c and fig 8 all show it.

42

The only exception to that was when the ignition timing was over advanced for the purposes of the test to 45BTDC. Even then, as the report points out “the fact that the temperature of the exhaust valve becomes greater than the temperature of the exhaust gas thermocouple is of no significance because the true exhaust gas temperature is greater than the thermocouple”.

We ran the test confirming this about 15 years ago.

...the NACA report has been declassified. It is in line with what is in the textbooks. Maybe it is time you declassified some data from 'your' test seeing as your conclusion is at variance with the NACA report you cite.

[Eddie Dean]

Oggers
I have worked with several operators and Chief Engineers over recent years, all of them are against the APS LOP theory and have warned their pilots of such.

I have no dog in this fight, but find it intriguing that the APS people treat their theory as valid and everybody else's opinion as sh1t

[Ultralights]

but find it intriguing that the APS people treat their theory as valid

its hard to argue against cold hard facts. measurable, repeatable facts. without factual data, all you have is opinions..

[Aussie Bob]

Eddie, it would also be highly probable that the said aircraft operated by the said operators and maintained by said engineers lack proper engine monitoring.

Without proper engine monitoring I would warn most pilots to ignore APS LOP theory too. You are shooting in the dark a bit without instrumentation. That said I would trust Jabba, John or Walter to operate any engine I know of, regardless of instrumentation in any way they thought fit.

[Lead Balloon]

Oggers
I have worked with several operators and Chief Engineers over recent years, all of them are against the APS LOP theory and have warned their pilots of such.

I have no dog in this fight, but find it intriguing that the APS people treat their theory as valid and everybody else's opinion as sh1tSomeone connected to the APS shysters has managed to scam the FAA into approving a flight manual supplement for LOP operations for Gami-jector equipped engines: http://www.gami.com/gamijectors/afms%20-%20gamijectors%20rev%20ir.pdf

I felt so much safer after I put those pages in my aircraft's flight manual last week, having run the engine LOP in cruise ever since I got it years ago. :rolleyes:

[Eddie Dean]

Lead
Purposely obtuse or are you trying to draw me into this supercilious discussion?

Edit: in fact there's a private operator here that Dave knows well, Dave flew with him at Caboolture, and when he comes in for the next 100 inspect I will help him set the system as APS want.

[Lead Balloon]

"Purposely obtuse"?

Not purposely, but I'm not sure of what I am being accused and against what, precisely, the "Chief Engineers" to whom you referred are warning.

You said:I have worked with several operators and Chief Engineers over recent years, all of them are against the APS LOP theory and have warned their pilots of such.Let me do my best to avoid any accusation of being obtuse: The "Chief Engineers" to whom you refer are ignorant, if their "warning" is on the basis that there is anything fundamentally more risky about running LOP than ROP (or peak) EGT.

I use the word "ignorant" to mean "lacking in knowledge" and "uniformed on the subject", per the Concise Oxford Dictionary. My shorthand for those definitions would be "stupid", but that's a personal view rather than one supported by dictionary definitions.

Sufficiently "un-obtuse" for you?

[Eddie Dean]

I apologise, perhaps you are just ignorant. You missed the point and went on some belligerent rant, as always when you are presented with an apposing view.

BTW that is not the definition of obtuse.

[Jabawocky]

oggers, you are simply not correct.

Let me repeat your statement.
This is not correct. NACA-754 of 1943 shows clearly that valve temps track EGT. Figures 7a, b, and c and fig 8 all show it.

Time to put your glasses on, figure 8 clearly shows that statement is false.

Now have a close look at the full document; http://naca.central.cranfield.ac.uk/reports/1943/naca-report-754.pdf

This same data was repeated in tests done by Lycoming in the 1960's.

Look at how EGT and the valve temperature track. As you head towards Peak EGT (but still ROP) the valve temperature is falling. It did it back in 1943, it kept doing in in the 1960's and it does it in 2016 in my engine. Will keep doing it in 2020 too.

Now if you think APS data was just plucked out of our butts, think again. It is all backed by piles of data. I have stood at the panel of the engine dyno and even from the other side of the world watched the data of detonation testing (for the FAA) come streaming in live. I can assure you 100% the data is correct and has no opinion.

Now look carefully at the APS graphic which is provided for educational purposes and is relevant no matter what absolute values you care to use.
http://i849.photobucket.com/albums/ab58/jaba430/Landmarksgraph_zpsbfb07cbb.gif

Have a close look at the relationship of the 1943 curves of valve temperature and just trust for a minute the APS curves. Ask yourself what tracks the same as the valve temperature?

Then ask yourself what the driver of this temperature is? Is it the Red, blue, black brown or green curve?

When you study this, and come up with an answer please let me know. We can take the next step in understanding. :ok:

[Walter Atkinson]

According to the 1943 NACA report referenced, those who think that valve temp is in any way related to EGT must reconcile the fact that as EGT is going UP from 25dF ROP to peak EGT the valve temperature is going DOWN. This is definitive evidence that the two are NOT related. Maybe one needs to look at the data more closely. This was confirmed by Lycoming in 1966 and again by GAMI more recently.

Valve temp is NOT related to EGT, it is related to something else... a study of the chart Jabber posted will reveal the answer.

The problem is that the physics are everywhere the same. Opinions may not be.

The second problem is that one may choose to believe unsupported opinions or the hard data. To each, his own.

As for providing a link, that is easy. Go the the APS website and sign up for the online course where 16+ hours of hard DATA are presented. It is the equivalent of a semester course, not a simple SAE "paper." Where I went to school, one had to pay for the education.

Dig in or not. Educate or not. It's a call each must make for themselves and it matters not to anyone else.

We have spent a decade and a half dealing with the types of unsupported statements made in this thread and in not a single instance have the unsupported opinions held up to the science. Take your best shot. Send us some data.

[Walter Atkinson]

LOP theory?????

That is truly funny.

It's factual. One might enjoy reading Taylor's two-volume engineering texts--or Haywood's texts.

I've read both.

It's true. There really is a time machine and we've all gone back in time. This thread proves it.

[Eddie Dean]

Perhaps so Walter, but then again it may just show the arrogance of some when asked simple questions by a dumb (arse) ass mechanic.

[Ultralights]

actually, LOP Theory is correct terminology.

Theory. 1.
a coherent group of tested general propositions, commonly regarded as correct, that can be used as principles of explanation and prediction for a class of phenomena:

[Lead Balloon]

Errrm, no. There are no "principles of explanation and prediction" here.

We don't say that the sun rising in the east is a "theory", notwithstanding that we predict it will happen each day and we have explanations for it.

[Eddie Dean]

Errrrrm no, the sun rising in the East is fact.
Where as LOP is by definition a theory that holds true as ultralights has written.

BTW thanks "old mate" that was a great and enlightning discussion.

[Lead Balloon]

So "ROP" is a "theory" as well? :rolleyes:

[Eddie Dean]

I don't know, only did 3rd form education.
You're the intellectual , you tell me.

[Lead Balloon]

Me an intellectual? Bwaaahaaaahaaaa :)

Maybe we just have to agree that anything to do with reciprocating engines is ... faith-based ... :ok:

[Eddie Dean]

Thanks lead and may your love tank be filled to the brim with aviation
Cheers

[sillograph]

So all that old data what fuel is that based on...

You could say in the past people may have had access to 100/130 avgas so 100 octane lean of peak and 130 octane rich of peak.

If that fuel was still available would the LOP discussion still be going on?

Ducks and hides.....

[Jabawocky]

The fuel used matters not, the relationships are all the same, be it 100/130, 100LL ordinary mogas or G100UL. The LOP/ROP relationships remain.

It is all about detonation margin and using the suitable fuel for your engine.

[sillograph]

All I was saying was if we could still get 100/130 fuel the majority may still prefer the extra power of 130 octane but the only way to get it would be ROP.