How to thread drift in 720 posts!!! [Archive] - Page 2

cockney steve

12th Apr 2014, 12:07

@ No Hoper Again , you raise a red herring....IF the starter was sufficiently fast to throw-out the impulse coupling, that would indicate that the engine manufacturer thought retardation and impulse were not required at that rotational speed....QED.
What part of "IF are you having difficulty with? ;)
The whole thing is hypothetical. If you re-read all the thread, someone suggested that the high torque permanent magnet starters are BAD because they crank too quickly.....I was merely pointing out that, IMO this is a half-baked argument and gave the justification for my reasoning.....It has yet to be refuted.
I do not make a habit of flooding engines. A lifetime of fettling 2-strokes, 4-strokes, Agricultural, Marine, Aviation and road, have given me some understanding of the applied physics involved....Again, my description was meant to be an analysis of each compression stroke event on a cylinder during the starting phase.
Although there is a large "technical" section to the UK PPL, It seems the majority of PILOTS learn by rote and can repeat parrot-fashion without any understanding of the subject they are repeating......like a book, all the info is there, but it's too dumb to use it.:}

I once knew an engineer who had trouble with a gas appliance.....When I explained that a thermocouple produced electricity , when heated, He told me in no uncertain terms that I was extracting the urine and talking cobblers He only backed down when a random customer was asked how the device worked and repeated the answer.

Another refused to believe the theory behind "stretch-bolts" for accurate cylinder head/block tightening.....He had to physically "feel" them go on the last angular tightening, before he understood why they are a "once-only" use for their intended purpose.

We must be receptive to new applications of science and new scientific discoveries......Stab-proof cloth (Kevlar) ? Carbon-fibre structures? how many people thought these were flights of fancy when they were announced?

Flying with eagles isn't a problem (keeping up with them is another story )

watching out for the dinosaurs is where the problems start.:8

Jabawocky

12th Apr 2014, 12:44

Yr right

Which casa solicitor and how was it he was trying you on?

They come in for enough stick from me included but you can't make that claim and not back it up.

How is it you defended us all from the forces of evil?

yr right

12th Apr 2014, 13:00

We'll Jaba it's all on the public recorded. Some people on here know about it and ive help them out with there dealings. As for me saying what happen we'll I'm not about to tell you or anyone else sorry.
Cheers.
Lets just say I'm no dumb f:$k.

gerry111

12th Apr 2014, 14:11

yr right,

Quote: "Let's just say I'm no dumb f:$k."

I will never say that you are, on this thread.

But perhaps what you need to appreciate is simply this: The other people contributing to the LOP debate aren't necessarily dumb f:$ks either. And when some of them base their arguments on credible maths and science, then I tend to listen to them.

If you make a claim here, then it's quite reasonable for others to expect you to back it up with facts.

Please pardon me for being brutally honest with you, though. Were CASA to haul me in for some alleged aviation naughtyness, you wouldn't be my most preferred choice of counsel.

yr right

12th Apr 2014, 15:29

well gerry lets just say that may be a mistake on your behalf then.
As for facts its hard to produce that when you don't know what you to be tested on. Like I've said previous we don't record dead cly that's the fact and at the end of the day I see the facts and its a fact that I see those facts and them facts arnt so good because as a fact the fact is that fuel is still the cheapest thing you can place in an aircraft and that is also a fact.

So the average GA private plane which dose less than 100 hours a year going to save what less than $20 an hour go for it im happy for you to do it.

Cheers

drunk_pilot

12th Apr 2014, 15:48

Hello all,

Gerry 111 addressing yr right:

If you make a claim here, then it's quite reasonable for others to expect you to back it up with facts.

Why? He doesn't have to back anything up. He was asked his OPINION on LOP operations, and he has given plenty of it. I personally know 'yr right' and have flown aircraft maintained by him. He is very passionate, thorough, knowledgable, and will always err on the side of caution, giving regard to what the book says.

Which brings me to my next problem. This quote may or may not be taken out of context, but is irrelevant in my opinion:

Now assume that I was flying, ROP, the way the POH says I should, and this happened.

This is part of one of the testimonials on the Advanced Pilot website that 'Jabbawocky' shared earlier in the thread. Now I don't have an issue with an aircraft owner operating their aircraft LOP, providing the BOOK SAYS YOU CAN! Why is Advanced Pilot advocating operating outside the POH? Because they know better than the OEM? Maybe, but is Advanced Pilot going to be held accountable in the event something goes wrong while their customer is operating outside the POH with their new found knowledge? Bearing in mind, in. Litigation, that any failure doesn't necessarily have to be related to operating LOP, if it can be proven that the pilot was operating outside of the POH. It doesn't matter if you know better than the OEM, you are bound by the POH!

For example, when Beech certified the original King Air 200, it had 850SHP PT6A-41 engines. They certified the King Air 200 take-off and landing data on this configuration. Fast forward a few decades, and we now have the B200GT with improved PT6A-52's, but, beech still use the original take-off and landing data from the earliest king airs (to save money re-certifying the data). We all know that the new one will get up and go in less distance (particularly hot and high), but try getting that past CASA when you decide to go outside what the OEM says because you know better!

If the POH allows for it, fill your boots. It doesn't mean that 'yr right' has to recommend it to people. He has his reasons, and he doesn't have to provide graphs to the peanut gallery on here. He's not advocating anything radical, he's advocating good common sense, and following the POH.

Regards

jdeakin

12th Apr 2014, 15:56

If John Deakin is reading this he will no doubt offer his view of the statistics so far over 13 years and thousands of students.I'm a little reluctant to participate in this forum because of the "no advertising" issue. I'll also confess that I personally don't like the "hiding behind phony names." I prefer to sign with my real name, and stand behind what I say.

I happen to know Jabawocky's real name, and agree 100% with what he says about engines. I have read the entire thread to this point, and he is a voice of reason in an ocean of ignorance. :) An ocean which I confess to sharing before 1992 or so. Yes, I too was ignorant.

There are a few others who have the picture. Good on ya, mates!

We have offered the following guarantee since we started, almost 15 years ago. "If you complete either course (ONLINE or LIVE) and do not feel it was worth the money, we'll give you your money back."

There are thousands of people who have taken them, and NOT ONE has ever exercised that option. Never. About six have stood up in class and announced to all, "You guys are not charging enough for this!" Unsolicited.

Now, sooner or later, someone will, and then I'll have to say, "Only one has asked for his money back." :)

Best...
John Deakin

jdeakin

12th Apr 2014, 16:09

On the Lyc (Bendix) system, the pump is merrily pumping away, potentially supplying more fuel than the engine needs. The FCU simply limits that output via a diaphragm which responds to pressure drop across a venturi, to arrive at the desired flow. The pump can go as hard as it likes, but the FCU controls flow. That's why the flow doesn't change when you switch on the boost pump and raise the input pressure.

Sorry, but you lost me ages ago when you claimed that TCM and Bendix systems work the same.Correct for the Lycoming! Well said. Also very common on the wonderful old big radials of yesteryear. Run the engine RPM up and down, and the fuel will change via the Bendix Pressure Carburetor and airflow.

Most CMI (Continental) engines have a MUCH simpler system where the engine-driven fuel pump is driven by the engine (direct gearing), and the output is variable with engine RPM. Run the engine RPM up and down, and the fuel flow will also change, directly with the RPM.

Both systems have their advantages and disadvantages. For the most part, they are transparent to the pilot.

No Hoper

12th Apr 2014, 20:03

Cockney Steve, I once knew a pilot who believed that jet thrust pushed on the air and made the aircraft move forward ....... See how easy it is to make sh1t up.

I reread your post 223 and it reads as a statement of facts of how you flood start your engine and more info on this high speed starter.

Aussie Bob

12th Apr 2014, 21:13

Why? He doesn't have to back anything up.

Drunk Pilot, if you read all of yr rights posts on this forum you will have to come to the conclusion that he states lots more than just opinions. yr right has been asked to back up his statements numerous times. It is something he is incapable or not interested in doing.

No he doesn't have to back up anything, but his credibility suffers as a result of not doing so.

No Hoper

12th Apr 2014, 21:28

Aussie Bob, as a practicing LAME and part time auto mechanic , this thread is proving to be a refresher course in aero piston engine theory and application.
It would only improve by Yr Right contributing his data similar to Jaba et al.

Jaba, was speaking to young RV7 owner/pilot, he uses the APS system but didn't quite understand the theory of operation. Perhaps some of your students are learning by rote?

yr right

12th Apr 2014, 22:46

Brian Abraham

12th Apr 2014, 22:47

He's not advocating anything radical, he's advocating good common sense, and following the POHdrunk_pilot, trouble is, with respect to LOP, he is also advocating not complying with the POH. The Chieftain POH permits LOP operation, but yr right is yet to explain why it's a bad idea to comply with the Chieftain POH.

yr right

12th Apr 2014, 22:52

Woops and no No Hooper. That was not directed at you in any shape or form. Be fore you jump up and down.
Next drunken pilot. Pm so I know who you are. The drunk part dosent quite narrow it down quite enough. But thanks for your input.
Cheers

yr right

12th Apr 2014, 22:56

Negative brain I've said do what you like. If it's in the poh do it. I've also said that no org that if worked for that I have known has ever used LOP on the tsio-540 and LTSIO -540 engines.
Cheers.

No Hoper

12th Apr 2014, 23:08

Yr Right, didn't consider it was. I have the same issues with owner/pilots that you allude to. I'm on the road doing contract work when inclined.
Agree that the CP of orgs that I have been associated with have banned LOP operations. Maybe Commercial pilots are less skilled than private/ RAA pilots

rnuts

12th Apr 2014, 23:11

We, as pilots and engineers are bound by rules and regulations. We are expected by the authorities to operate and maintain by the books period.
If your POH says you can operate LOP then fill your boots.
If your maintenance manual says do this, then that's what you are expected to do.
If you operate outside, or maintain outside those parameters then you do so at your own peril.
If you end up in court or worse for whatever reason, they will ask," did you do it by the book". They don't care about good intentions or data.
None of us want to be playing Mummy's and Daddy's with Bubba, I'm sure most would agree.
:)

No Hoper

12th Apr 2014, 23:25

Rnuts, very valid points. Also ensure your approved data is at current revision status. When certifying record what data was used and results achieved. I also keep a separate diary, which has been used as evidence in an AAT hearing.

Mmmm non consenting sex with Bubba

yr right

12th Apr 2014, 23:57

I know of a case where we set up the engine only to have the owner come back and say it was not running right. Attached the gauges was out by a long way. Approached the C/E said some one has tampered with it. Reset the fuel system again, then he came back again with the same problem, done it again with the same out come. Sent it away. Came back again same problem this time we made our own colour tamper proof mix and applied it. Guess what came back again. The costumer was given his log bogs and go to another shop. He had been adjusting it himself.

Chers

yr right

13th Apr 2014, 00:02

I will add here. The only time I ASK a pilot to run an engine the way I wont it done is if im trouble shooting a problem or im running in a new engine, Other than that its his domain and I don't tell him how what why any thing
And as for running LOP that a commercial decision made people higher up the food chain than my self.

Cheers

rnuts

13th Apr 2014, 00:07

Had one guy who owned a turboprop thought he knew all about it.
He fiddled with the compensator so his gauges would match and then proceeded to cook his engine.
That was an expensive mistake.
He left us to it after that

Old Akro

13th Apr 2014, 00:11

We, as pilots and engineers are bound by rules and regulations. We are expected by the authorities to operate and maintain by the books period.

Yes, but most Pilot operating handbooks and engine operating handbooks are vague where it counts, and are frequently not in full agreement.

Also, most POH / EOH's were written assuming that the aircraft has less instrumentation than is common now.

This is all a bit academic because the only case I can recall where engine operation was an issue is Whyalla. And in this instance CASA were internationally pilloried and nearly 15 years later CASA's reputation has not fully recovered.

If we are called to account in court, we will be required to justify our actions. Adherence to a manual or regulation is the easiest way to do this, but not the only way.

Agrajag

13th Apr 2014, 00:19

I said it before and I'll say it again. Had I known when I first started I would have collected ever cly and when why what etc so in 2014 I could post it on this site. Now I didn't. So ok all you fellas out there with all your experience and thousands of flight hours and your own data and of course you have your own data don't you. With the exception of Mick which seams to collect his own data via trends I bet none of you collect it.

You might be surprised to learn how many of us do. And how that enables us to correlate, very closely, our actions during a flight and the direct result they have on the engine parameters. CHTs, EGTs, fuel flow, MAP... got 'em all, in real time.

But there I go, using that pesky and misleading "data" again. Sorry.

Now I'll say this again. The fuel pump is a pump. It is controled by the fcu. The pump is a follower it is a sheep. It follows. Also I find it allitle strange that no one has said any thing about the changes that tcm have made. Maybe wow could I be right and you can't discredit me.

Wrong, yet again. The fuel pump on our Bendix system is not "controlled" by anything. But what happens after the fuel leaves the pump... that's another thing. And, again, the pump on a TCM system is driven differently and its ultimate output to the injectors is regulated differently. I still don't understand how, in a technical discussion, you can make these sweeping statements to imply the two systems work in the same manner.

Please don't resort to the tired defence of "I'm a LAME and you're not", as though that should shut down any disagreement. You've already demonstrated some gaping holes in your knowledge. I'll accept any assertion you care to make, and learn from it - if you can prove it.

Equally, even mere opinions are only valid if they are based on something factual. Otherwise they're just hot air.

And so, to POH techiniques...

A POH contains certain limitations which must be observed. These include weights, CG ranges, max RPM, min oil pressure and so on. The POH will also tell us optimum and limiting speeds for different phases of flight, for use when needed.

But there's a lot of content which is advisory only, and much of this relates to how to achieve desired power outputs from the engine. These are not published as limitations, and so aren't mandatory. If the POH doesn't specifically prohibit, for example, LOP operation, then it's fair game.

This is distinct from an approved Operations Manual in a commercial environment. If I'm operating in such a context, then you bet I'll comply with the way the Ops Manual says it should be done - even if I don't agree with it. The same goes if I'm renting. I'll do it the way the owner wants.

But when I'm flying privately in my own aircraft, the rules are different. Our POH is also an approved document, and it's deliberately vague on the finer points of engine management, which allows the informed pilot to do what is safe and sensible.

No Hoper

13th Apr 2014, 00:38

Agrajag, you and I may believe that some approved data is advisory only. The courts do not. Any data from the OEM or other approved entity is viewed as mandatory unless you can prove otherwise

yr right

13th Apr 2014, 00:38

Mmmm I say it again. the FCU controls the fuel pump. If you add more throttle and increase your RPM the pump moves faster and increases its flow in such the pump is is controlled via RPM with in turned is controlled by the FCU which is controlled by the Pilot.
Hence you could say that the FCU is the brains behind the fuel system.

This is true for all EDFP which may be a turbine or a combustion engine.

Also what you are measuring is engine trends I don't and no one I know runs a book on what components are breaking and at what time, how ever if we notice we have a problem showing up we can go back and look at what we put on via P# etc from stores and see whats happening.

It surprising how different pilots treat the machines and is quite noticeable when you have a dud pilot and see that problems they cause and then when they leave the problem goes away and the problem restarts at a different place

Cheers

rnuts

13th Apr 2014, 00:39

Agrajag.
Did the manufacturer of your aircraft tell you that they had made the POH vague for that reason or is it an assumption on your part.
If they had to put in everything, you would have a POH that you couldn't carry due to the weight limitations of your aircraft.
Yes, I do agree times have changed, instrumentation has advanced but you can't just make stuff up to suit what you believe without approval from either the authority or the manufacturer.
Just cos it's not in there doesn't mean all bets are off.
Unrelated to aviation but there was a case in the states whereby a new owner of a Winnebago turned on his cruise control and proceeded to go down the back and make a cuppa which then resulted in a crash and lawsuit.
He won cos it wasnt written in the handbook not to do that.
I'm not saying we are in the same situation here but Geeezus.
I bet the handbook for a winnebago is now more comprehensive.:ugh:

Agrajag

13th Apr 2014, 01:19

Did the manufacturer of your aircraft tell you that they had made the POH vague for that reason or is it an assumption on your part.
If they had to put in everything, you would have a POH that you couldn't carry due to the weight limitations of your aircraft.
Yes, I do agree times have changed, instrumentation has advanced but you can't just make stuff up to suit what you believe without approval from either the authority or the manufacturer.
Just cos it's not in there doesn't mean all bets are off.

OK, I'll fess up. :)

It's a homebuilt, so I'm listed as the manufacturer, and I wrote the POH based on some existing examples. It's still an approved document though, and the inspector checked it as part of the C of A issue.

I take your point about "making stuff up", and I agree that they can't put everything in, but that may just illustrate my position.

When we fly it, we can do a max rate climb, cruise-climb, fly for range, fly for speed, fly for endurance, do a glide descent, cruise descent, max-rate descent or something else that happens to work on the day. The POH, even from a factory manufacturer, can't hope to cover everything that might occur during a flight. It includes limitations and prohibitions, which we observe, and some helpful guidance. The rest is left to pilot judgement.

Without a specific limitation, and while remaining within the designer's published operating envelope, we do what's safe and sensible. Thankfully we are still regarded as having a little more commonsense than the typical Winnebago owner!

Oracle1

13th Apr 2014, 02:02

If the POH told you to jump off the Sydney Harbour Bridge would you do it?

"Also what you are measuring is engine trends I don't and no one I know runs a book on what components are breaking and at what time, how ever if we notice we have a problem showing up we can go back and look at what we put on via P# etc from stores and see whats happening."

No one I know keeps a book either but we do have computer software that keeps all 20 PT6 engines trends in our fleet monitored, tells us what is due and if a component fails before it is due it becomes obvious very quickly

yr right

13th Apr 2014, 02:08

Agrajag
I can asure you I would have forgotten more about fuel systems than you would know.
Cheers

yr right

13th Apr 2014, 02:12

Agrajag.
Statistic of the Sunday nights news.
Cheers

drunk_pilot

13th Apr 2014, 02:20

Oracle1:

If the POH told you to jump off the Sydney Harbour Bridge would you do it?

I'm not sure who you're having a go at, but in any case: Those who
are suggesting that if the POH doesn't specifically prohibit LOP, that you are free to do so need your head checked. Most POH's state that whilst interpolation of
published data is approved, extrapolation is not. If you
Don't have charts for any leaner than peak EGT, any operation beyond that is extrapolation, and you are now a test pilot.

Regards

yr right

13th Apr 2014, 02:27

Pt6 trends are required as part of the ad. If you are running 20 pt6a then you are in a different mode to the ga owner I was more referring to. 20 engines is a sizeable fleet and I would think that you would be more on top of things than you may know.
Cheers

Hempy

13th Apr 2014, 02:32

Agrajag
I can asure you I would have forgotten more about fuel systems than you would know.
Cheers

Now see mate, this type of comment is just rubbish really, and it just makes everything else you say look equally rubbish. You can ASSURE us? That would imply that you not only know Agrajag personally but you also know exactly what he's learned in his life. It would also suggest that you have some form of evidence to back up your claim. This would be interesting, because other than repetitive bleating about how many engines you've fixed, actual real evidence seems to be sadly lacking.

Champ, go have a Bundy and a winny blue, iron up the flannel and head out for a parma, chill out on the pokies, drive home blind, crawl into bed and give the mrs(?) a tap on the shoulder. You'll feel much better...

Walter Atkinson

13th Apr 2014, 03:03

Carbys running LOP and Such:

The use of Carb heat is NOT recommended to be full ON. There is an optimal carb temp which results in optimal fuel vaporization. It is that carb temp that results in the lowest DIF number with the least carb heat application. THAT is what you should be using. Once found, it works at all OATs. (BTW, in all installations I have tried this on, that temp will be above freezing and carb ice is not an issue.)

Danger of mixtures:

The most dangerous mixture is approx. 40dF ROP. Why? The data proves that that is the mixture which results in the highest CHTs, highest internal cylinder pressures and the least detonation margin. ANY mixture richer or leaner is less of a problem.

EMS:

They "can be used" to lean an engine but that is NOT why you should have one. They are valuable tools in saving your engine and your life.

DATA:

A person without data is just another person with an unsupported opinion.

We each should decide from whom we take advice and trust. For me, if you do not have data to back up your claims, I'll drink a beer with you, but I will give little credence to your "opinions" of science.

We have been listening to a few folks in this thread who have no data but have some pretty strong opinions. One would hope that on a good forum like this, that these folks would figure out that they are a tad shy on understanding based on facts, but are comfortable using unsupported opinions to make important decisions. An introspective sort would probably go get some education to correct that. Unfortunately, it is commonplace for the very ones who need the most education to be the least inclined to get it.

Let me ask: How do you know when you are right?

Unless you are willing to constantly challenge what you think is right and try to prove yourself wrong, you will, without a doubt become wrong.

We are watching this in real-time.

Walter Atkinson

13th Apr 2014, 03:09

***Champ, go have a Bundy and a winny blue, iron up the flannel and head out for a parma, chill out on the pokies, drive home blind, crawl into bed and give the mrs(?) a tap on the shoulder. ***

I am a southern boy from the U.S. I wish I had a clue what that sentence means 'cause it sure sounds eloquent! I am impressed. No wonder the Aussies were such incredible allies during WWII. If an Aussie couldn't shoot the bastard, he could talk the poor bugger into confusion. :ok::D:=:confused:

No Hoper

13th Apr 2014, 04:48

Translation for Walter
Have a bundy and winnie blue- drink a bundaberg rum and have a cigarette
Iron up the Flannel- iron a shirt
Head out for Parma- go for a meal
Chill out on the pokies- play the poker machines
Drive home blind- drive home drunk
Give the mrs a tap on the shoulder- that's Aussie foreplay

Avgas172

13th Apr 2014, 05:52

I'm thinking Yr Right has forgotten so much he can't remember anything useful at all, I struggle to believe any LAME can forget a Continental 0-300 has 6 cylinders not 4 and an output of only 100hp as described by Mr (Ms) Right ...:hmm:

LeadSled

13th Apr 2014, 06:25

It's a homebuilt, so I'm listed as the manufacturer, and I wrote the POH based on some existing examples. It's still an approved document though, and the inspector checked it as part of the C of A issue.Agrajag,
If your aircraft is a home built aircraft (Experimental Amateur Built) you do not have a C.of A. Even if it is the very old style AABA certificate, the document is still not a type certified C.of A.

Your "POH style" document is not "approved" by anybody except you, it is just part of the document package you submitted to get whatever certificate, on which you fly.

"Certificate of Airworthiness" and "approved" have very specific legal meanings in certification terms, they are not generic terms.

All that makes absolutely no difference to how you operate the engine, or operated it properly. The engine doesn't care what bit of paper enables the aeroplane, to which it is attached, to legally ( or otherwise) get in the air.

Tootle pip!!

Agrajag

13th Apr 2014, 06:52

Agrajag,
If your aircraft is a home built aircraft (Experimental Amateur Built) you do not have a C.of A. Even if it is the very old style AABA certificate, the document is still not a type certified C.of A.

Your "POH style" document is not "approved" by anybody except you, it is just part of the document package you submitted to get whatever certificate, on which you fly.

"Certificate of Airworthiness" and "approved" have very specific legal meanings in certification terms, they are not generic terms.Yep, agreed. I was perhaps a bit casual in tossing around such definitive terms in the context of an Experimental. But my point (perhaps not well made) was that there is much omitted or only vaguely covered, and therefore left to good judgement, even in POHs for certificated aircraft. On that, I suspect we also agree.

LeadSled

13th Apr 2014, 07:29

------ and therefore left to good judgement, even in POHs for certificated aircraft. On that, I suspect we also agree.

Agrajag,
Maybe, maybe not.

The starting point, for US manufacturers (including Boeing) is than an aircraft will be crewed by suitable trained and licensed pilots, and the Operations Manual (by whatever name, FCOM, POH) assumes a level of knowledge and competence for those who will fly their aircraft.

Thus, what is expected to be normal levels of basic aviation knowledge will not be repeated in a POH or similar.

These documents will contain a level of "certified data", and a range of "approved data". Generally but not always, the "certified data" will be in a section called "Limitations". Quite what is what, legally, in an Operations Manual (which will be normally nominated by Manufacturer's Part Number in the Type Certification Data Sheet) doesn't matter, it is a compilation of selected information that is basic to operating the aeroplane.

What you choose to put in your equivalent to a POH is entirely up to you, the mandatory bit is the appendix to your certificate, as issued by whichever delegate issued your Experimental Certificate.

Mostly I do not have a very high opinion of most POH for smaller aircraft, but those manufacturers who have adopted the GAMA format are getting better, particularly if the manufacturer has produced the document in conjunction with Flight Safety Inc.

GAMA is a reasonable format, but it would have been even better if GAMA had followed the format used by the USAF and the USN, and adopted by Boeing, as the (not mandatory) ATA system.

A manual in this format, as a POH, would be really easy to use, it is simple and logical.

Tootle pip!!

A Squared

13th Apr 2014, 07:36

What I said was the ACTUAL spark timing , when the plug actually fires is anywhere up to 13-16 degrees BTDC. I can show you this on the dyno runs during the APS class.

Jabawocky,

I'm curious about this. Where does the delay between the opening of the points and the firing of the spark come from?

Current in the primary windings continuing to flow after point opening as the capacitor across the points charges?

Time for the field in the coil to collapse, producing the current in the secondary winding?

Something else?

yr right

13th Apr 2014, 07:55

Define data. Define imagination. Now show data in real life as opposed to just graphs. Your argument if there was a no cost may be valid. When you place a cost on it and some one is making $$$$ from it I am sorry but you now you are compromised in your own opinions.
My data is in real life hands on. I learnt my trade the hard way. I hard to learn it. The teaching was only part of it. The hard yards was doing a lic when you hard to get the books find the information do the exams I think we had 4 sittings a year. Then pass the exams.
So you think it's easy I challenge you all to go do some exams get a pass then get some experience then make some comments.

It's not my imagination to the damage I have seen it data. So if you won't graphs go some where else and get them. If you won't hands hangar floor data just ask. If you don't like the answer that's fine. But you don't need to make a song and dance over it. So when you ask my opinion I gave it. If it dosent suit your model that's fine but you have had to pay for it ethier.

Cheers.

yr right

13th Apr 2014, 08:04

Jaba
Yes I am wondering the same. Even if that is the case I am sure that the engine manufacture has taken this all into account and thus change there timing to suit as they do.
Next thing as I've said a magneto has a multiple discharge on collapsing of the field. So there is more than one spark per firing across the plug gap.

Really it is not relevant as you cannot change from the settings that they provide.

Now next thing how do we check our mixture setting on a run. Is there a difference between tcm and a lyc ?
Cheers

Agrajag

13th Apr 2014, 08:07

------ and therefore left to good judgement, even in POHs for certificated aircraft. On that, I suspect we also agree.

Agrajag,
Maybe, maybe not...

Again, no dispute.

I think, informative as this branch of the discussion is, it may have strayed from the context in which it began. Specifically, it related to whether LOP operation is a breach of a manufacturer's limitations as published in a POH. There are those who say, if it isn't specifically approved, it's therefore prohibited. The gentlemen at APS disagree and, given that this is their area of expertise, I'm inclined to believe them.

yr right

13th Apr 2014, 08:17

Negative ghost rider. If it's not stated and you don't have or have an stc you can't use it. It is that simple.
You cannot make your own rules.

Cheers

Ultralights

13th Apr 2014, 08:21

Don't have charts for any leaner than peak EGT, any operation beyond that is extrapolation, and you are now a test pilot.

actually most engines do, and i have seen the data, and seen all types of engines run LOP.. plenty of data around on LOP ops, so much so, that i doubt anyone would be a test pilot when it comes to LOP in any aircraft..

a test pilot implying that the pilot is flying without any knowledge of what will happen when operating the aircraft in its current setup/conditions..

yr right

13th Apr 2014, 08:36

Um I think you are reading to much into test pilot some what.

LeadSled

13th Apr 2014, 08:45

Negative ghost rider. If it's not stated and you don't have or have an stc you can't use it. It is that simple.
You cannot make your own rules.

yr right,
Maybe that is what you think is the case, been taught, whatever, but it is not legally true, as far as aircraft certification is concerned. However, if one has been "trained" in Australia, either as a licensed pilot or maintenance person, I can easily understand how that legal misapprehension comes about.

As mentioned previously, a POH, by whatever name, is a combination of certified data, approved/acceptable data, and selected useful information for the operation of the aircraft by suitably trained, experienced and licensed crews.

In matters of LOP, if it is not specifically prohibited, it is permitted, as LOP is a quite normal operating mode for a four cycle (Otto Cycle) piston engine, aircraft or otherwise.

Tootle pip!!

yr right

13th Apr 2014, 08:54

No you cannot change data from something else to some thing else. Data is specific to the aircraft and not transferable between any aircraft that the data is required for.
If I have an stc or an eo its rego and s# limited, I cant use any document to any other aircraft period unless it is on that document. If you don't have data you cant use it. so if there is no charts for LOP as an example you cant legally use it. The regs are very specific on this.
I will add here this is for aust and I will not make comment on any other country regs, I also have held o/t lic coverage and approvals.
cheers

drunk_pilot

13th Apr 2014, 09:13

Leadsled:

In matters of LOP, if it is not specifically prohibited, it is permitted, as LOP is a quite normal operating mode for a four cycle (Otto Cycle) piston engine, aircraft or otherwise.

Oh really... So what happens when your aircraft POH only has performance tables for, say long range cruise leaning to peak EGT, which has a TAS and fuel flow attached to it, and some turkey decides he/she can make his/her destination in one go if he/she runs LOP based on their self derived data. How can he/she PROVE what performance they will achieve? Let's say they have an unforeseen headwind and suffer fuel exhaustion prior to their destination and have to land in tiger country. How successful do you think they'll be fronting the coroner over the death of a passenger because they extrapolated the OEM POH with their own, or anyone else's non-approved data? That's what I thought.

Quote:
Don't have charts for any leaner than peak EGT, any operation beyond that is extrapolation, and you are now a test pilot.

actually most engines do, and i have seen the data, and seen all types of engines run LOP.. plenty of data around on LOP ops, so much so, that i doubt anyone would be a test pilot when it comes to LOP in any aircraft..

a test pilot implying that the pilot is flying without any knowledge of what will happen when operating the aircraft in its current setup/conditions..

You quoted me out of context, Ultralights. I said IF YOU DON'T have charts for it. Read my first post a couple of pages back, if you have the charts and know what you're doing, go for it. Run LOP.

What really bothers me here, is that people are suggesting that just because the manufacturer doesn't specifically say don't do it, that you can! A little bit of knowledge is dangerous in the wrong hands, and this forum has a lot of new pilots reading, and getting ideas of stretching their dollar or range by running LOP, potentially without having any approved data or procedure in the POH to do it. You're asking for trouble saying that on here.

I'll say it ONCE more for clarity: If the POH says you can, and you know what you're doing, then go for it. But for your OWN sake, if you don't have the approved data to hang your hat on, DON'T DO IT!

Creampuff

13th Apr 2014, 09:36

Originally Posted by Jabawocky

What I said was the ACTUAL spark timing , when the plug actually fires is anywhere up to 13-16 degrees BTDC. I can show you this on the dyno runs during the APS class.When you set the timing to e.g. 22 degrees before top dead centre, the engine is not running. (That's why some people call it 'static' timing.)

When the engine is running the crank is moving. During the short period between the points opening and the spark occurring the crank has moved about half a dozen to a dozen degrees. It depends on RPM of course.

That's 'actual' timing.

The dyno data shows it.

And no, yr right, there are not multiple sparks out of a bog standard aero engine magneto after each points opening event. Just one spark, then some secondary 'ringing'.

yr right

13th Apr 2014, 09:41

Seriously leadsled before you make comment on law I suggest you know the regs first. You have made a rather large hole for your self and entered extremely dangerous territory that's not for the faint hearted.
You cannot add or subtract from the manual with out approved data. Its like saying you can do aeros in a metro cause you can do them in a pitts.
Really stop and think about what you have said.
Cheers

yr right

13th Apr 2014, 09:47

um points moved via a cam which is driven via shaft which has a gear attached which is driven via a gear off a gear which is attached to a crankshaft.no lost motion there !!!!!!!!!!!!

yr right

13th Apr 2014, 09:52

best let casa here know then cause they been teaching us all the wrong things, but hey you already knew that.

Creampuff

13th Apr 2014, 09:53

But when you set the magneto timing the crank isn't moving at thousands of revolutions per minute.

Why don't you just leave engine operation to the experts in engine operation?

yr right

13th Apr 2014, 09:59

yes I should so are you going to stop posting cause that be great
cheers

LeadSled

13th Apr 2014, 10:00

The regs are very specific on this. ye right,
OK, would you like to be very specific about the regulations, to which you refer. No generalization, very specific regulations, please.
You will quote the Australian certification standards post 1998 ie: the CASRs, of course.
Not anything that you believe may have been extant (but probably legally was not) at the time you did your apprenticeship.
I note that, in mid-1960s, I was operating VH- registered light aircraft LOP, even demonstrating the fuel savings to DCA Examiners of Airmen.

Its like saying you can do aeros in a metro cause you can do them in a pitts.
No, Its not anything like that, because the TCDS will tell me exactly what the certification base is for each aircraft, thus defining the flight envelope. Further, in the case of the Pitts, if it is certified in the Aerobatic category, the exact maneuvers permitted will be stated, if there are any maneuvers limitations. Once again, if there are no stated limitation, and maneuver physically possible is permitted, withing the limits of the design G.

Using another example, the Limitation for a B707/720 (all models) prohibited sideslips, therefor no sideslips. In contrast, sideslips ( which are NOT an aerobatic maneuver) were not mentioned in Limitations for B757/767/747/744, therefor sideslips were permitted. There was not, nor was there any legal requirement for, a specification that permitted sideslips.

best let casa here know then cause they been teaching us all the wrong things, but hey you already knew that. Yes, we do know that, what else is new??

Tootle pip!!

Jabawocky

13th Apr 2014, 10:07

WOW....has this thread wound up notch

Jaba, was speaking to young RV7 owner/pilot, he uses the APS system but didn't quite understand the theory of operation. Perhaps some of your students are learning by rote?
I doubt he is one of our students. We can't control what they do after a course, but we teach understanding....we avoid like the plague "cookbook recipes" because they do not work very well. By the way POH's tend to do this.

If you wish to PM me his details I can offer to help. Assuming he is a past student. Chances are I know him anyway. Even if not a past student!

Akro is correct.
Yes, but most Pilot operating handbooks and engine operating handbooks are vague where it counts, and are frequently not in full agreement.

Also, most POH / EOH's were written assuming that the aircraft has less instrumentation than is common now.

This is all a bit academic because the only case I can recall where engine operation was an issue is Whyalla. And in this instance CASA were internationally pilloried and nearly 15 years later CASA's reputation has not fully recovered.

If we are called to account in court, we will be required to justify our actions. Adherence to a manual or regulation is the easiest way to do this, but not the only way.

yr right
With the exception of Mick which seams to collect his own data via trends I bet none of you collect it.
Wrong again.

If you add more throttle and increase your RPM the pump moves faster and increases its flow in such the pump is is controlled via RPM with in turned is controlled by the FCU which is controlled by the Pilot. OK so what happens with a CS prop? The rpm does not change, but fuel flow especially with a Bendix system, is almost linear with mass air flow?

You really are getting confused here.

Yr right,
It is funny to watch you bury yourself even more. You do not know t but despite my thoughts on airspace ADSB and things being at odds with leadsled at times, he and I both know fact from fiction pretty well. It seems you unknowingly are slagging off at or refusing to be educated by several of the best heavy weights in aviation not only here but in the USA. All in this thread.

I am cocksure and ignorant at times, Leadie will attest to that, but I have nothing on you. You are blatantly disregarding thousands, maybe millions of hours of hard data produced by NACA (NASA), P&W, CW, Lycoming even validated it in the 60's, and more recently by GAMI and APS. All lock step in consistent data. The guys at GAMI I bet have seen as many if not more cylinders than you ever will. I cant be 100% sure, but I would bet serious coin on it.

Then you have been taking on several people who include experts (really...seriously top of the pile) in Aviation Law from not only senior airline positions but also regulators, and those also have engineering quals as well.

You have taken a poor attitude to one guy with well over 39,000hrs of flying (plus who knows how much not logged) in a list of aircraft from J3 cubs to B747, and some fiery beasts in-between, and that list is so long it is quicker to write the list not flown.

I just do not get it. You refuse to answer any question I ask of you, yet you get narky for missing one of yours, which I promptly addressed.

You do not have to believe me.....just the data.

In respect of your not wanting to paste the CASA fight on here, would you PM a link of the public record to me. I would like to learn some stuff from it. Seriously I do.:ok:

Creampuff

13th Apr 2014, 10:09

yr right, you appear to be labouring under yet another misconception. You appear to believe that the spark occurs at exactly the same instant as the points open when the engine is running. It doesn't.

It takes time for the collapsing primary current to cause the voltage in the secondary to build sufficiently to arc across the plug gap. During that time the crank is rotating. It's not long, but it's long enough for the crank to rotate half a dozen to a dozen degrees (depending on RPM).

The mathematics is quite simple and the reality in operation is measurable (and has been measured).

Leave operation to the experts.

PS: You are correct on one suggestion - the manufactures do take this into account in determining the static timing spec.

Jabawocky

13th Apr 2014, 10:15

AxA

Jabawocky,

I'm curious about this. Where does the delay between the opening of the points and the firing of the spark come from?

Current in the primary windings continuing to flow after point opening as the capacitor across the points charges?

Time for the field in the coil to collapse, producing the current in the secondary winding?

Something else?

Creamie has answered that already, but in addition to what he has described, there are subtle differences from some mag setups to others. On the Turbo 540 there are two kinds of magneto drives. Static timing can be set the same, the actual spark plug firing is a couple of degrees different.

In addition the spark firing moves quite a bit from one combustion event to the next. There is a bunch of dynamic stuff going on all the time including an amazing amount of crankshaft torsionals that are mind boggling when you see the data. This all adds up, and some of the effect is from the cycle to cycle variability of which there are about 20 per second.

Most of the variation is in the mechanicals before the points even get opened, but there is some variation there after as well.

All of this is challenging to the mind. And of course it does not really exist if you do not have the ability to measure it. But when you do....a whole new world of understanding erupts. All this good data is clearly stuff yr right knew but has forgotten. But it can be learned again! ;)

Andy_RR

13th Apr 2014, 10:48

I'd beg to differ on the ignition timing thing a little Jaba. Whilst there may be variation between dynamic ignition timing and static depending on engine speed (i.e. torsional vibration effects), at a constant speed the ignition timing is pretty consistent. Certainly less than a degree variation - you can see this clearly with a timing strobe as I have done on many test engines.

What does change from cycle to cycle is the ignition delay, which is conventionally defined as the time between the initiation of the spark and when the mass-fraction burned reaches 10% - that is 10% of the total heat energy has been released. This usually takes a very long and variable time compared to say the 10-90% burn time which is usually relatively more consistent. All of this is calculated from indicator diagrams - these days in real time with all the fancy DSP available to us.

The ignition delay is a function of how fast the flame kernel grows from the spark and depends on mixture ratio, preparation, micro turbulence, combustion chamber and gas temperature and probably also the phase of the moon.

Jabawocky

13th Apr 2014, 12:06

Andy,

I beg to differ that we differ :ok: Just watched a dyno run to double check this. The beloved Chieftan engine no less, and at cruise power variation was anywhere from 0-1 degree on any cylinder. At Idle / warm up it was typically double that.

So we are in extreme agreement. :) And this is normal. The average is also several degrees different to the static timing mark. This is the concept that yr right was struggling with I think.

And as Creamie has pointed out this is consistent with what the manufacturer designed it for.

We are all on the same page :ok:

Ultralights

13th Apr 2014, 12:39

https://fbcdn-sphotos-g-a.akamaihd.net/hphotos-ak-prn2/t1.0-9/1551479_792740774080269_62691064306530681_n.jpg

Lumps

13th Apr 2014, 13:04

You getting all this down Ilikeflying?

yr right

13th Apr 2014, 13:51

jaba leadsled just of a matter of interest how many CofA have you done and placed on the aust register

cheers

yr right

13th Apr 2014, 14:07

Jaba just as a matter of interest is the course you are running casa approved and are you an approved casa trainer under part 66 (sorry think part 66 late and can't be bothered looking it up.

Cheers

cockney steve

13th Apr 2014, 14:41

um points moved via a cam which is driven via shaft which has a gear attached which is driven via a gear off a gear which is attached to a crankshaft.no lost motion there !!!!!!!!!!!!
IO'll try and make this easy a
At hand-rotation, (s l o w l y ) the Static timing is set, say 20* BTDC

@60 RPM, that's 1 rev /sec =360* = 36* in 1/10 of a sec...agreed?
Ignore the speed of the points opening, for the purpose of this illustration, and call it instantaneous. You agree that there is a finite TIME taken for the Primary flux to collapse and induce a voltage into the secondary. ?
Now , the same engine is turning at 2400 RPM...So, in that same 1/10 of a second, the crankshaft has turned 144* (cos it's now doing 4 times the speed in the same amount of time.

THE SPARK- PROPOGATION IS TIME-CONSTANT, THE DEGREES OF CRANK- ROTATION ARE VARIABLE.

Therefore, timing between static and dynamic will vary and this is directly proportional to crank speed.

Similarly, the time taken for the mixture to burn and start expanding, is a constant for a given mixture-ratio,compression-ratio air temp. etc......but the faster the crank is revolving, the more degrees it will have turned in the TIME it takes for the fire to get burning.

The fixed- timing works because Aero-engines are virtually constant speed....Road- vehicles aren't . that's why they benifit from both mechanical and vacuum A/r or the current, sophisticated electronic brain controlled ones also use Lambda and knock-sensing.

Incidentally, 1-litre petrol cars are now commonly doing 60 mpg....20 years ago, you'd expect something approaching 40....this extrapower has come from a weaker mixture!...the same size gallon is now spread over50 percent more miles....agreed?
So, how come, the bane of motoring, BURNT EXHAUST VALVES has also virtually vanished in the same time frame.

A Squared

13th Apr 2014, 16:10

AxA,

All of this is challenging to the mind. And of course it does not really exist if you do not have the ability to measure it. But when you do....a whole new world of understanding erupts.

Thanks for the explanation. For the record I wasn't disputing that difference between static and effective running timing exists, I was just wondering what was behind it.. One tends to think of electronic events as happening instantaneously, even though, having spent considerable time staring at the patterns on an R-2800 ignition analyzer, I know better.

jdeakin

13th Apr 2014, 17:58

A comment on POHs in the GA world, if I may.

At the end of the weekend, George sits down with excerpts from roughly a dozen POHs, and points out "problems" in them for our class. Direct contradictions, in the same manual! Contradictions between manufacturers of different airplanes with the same engine! Contradictions between airplanes of the same model, identical engines, but with differing model years! After an hour of this, no one in the class views the POH as "divinely inspired" again!

In a recent class, George had just dissected a particularly egregious section of the manual, and the class was sitting there in shock that it would say such a ridiculous thing.

A voice came out the semi-darkness, saying "George, may I interrupt?"

"Sure, go ahead."

"When I was a freshly minted private pilot, and also a freshly graduated lawyer, I went to work as an intern at Cessna, in Wichita. To me fell the task of writing the POH for that year's Cessna 210. I will confess that it was I who wrote that specific language. It is only now, as a result of this weekend that I realize how very bad that POH was. I am deeply embarrassed by it."

And he sat down in dead silence.

Everyone here might do well to take a moment of equally dead silence to consider his words. He is highly visible person, well respected in aviation today. I certainly respect him for his candor.

POHs for GA aircraft contain a section on LIMITATIONs. If something is written in LIMITATIONS, you'd best pay attention to it. APS has never suggested anything against those LIMITATIONS, and I doubt we ever will. In general, they have been reviewed very carefully by experts both at the factory, and by the FAA. They are short, clear, and to the point.

The section on PERFORMANCE is much the same, for it contains the results of actual testing, and as such is HARD DATA.

The rest of the material, I'm sad to say, runs the gamut of quality, from "pretty good" (Cirrus) to "abominable." In many POHs it is material written by inexperienced people (some not even pilots) to satisfy the FAA and the inexperienced CFI with 400 hours. The FAA has even stated time and again that "Limitations are required, everything else is optional."

If CASA has gone beyond this, it is a tribute to the remarkable institutional stupidity of that organization, amply and vividly demonstrated by the Wyalla Report. It needs to be changed. How to change is above my pay grade.

So please, do what you must to satisfy the morons who work there, but DON'T make the mistake of thinking they are right, when they are most definitely not in suggesting the "How to fly" text in the POH came down from Mt Sinai, along with the Ten Commandments.

No Hoper

13th Apr 2014, 19:14

No one would dispute that there may be a difference between static timing and dynamic. The initiall proposition was that the difference was in the order of 13 degrees or more. A degree or so is the allowable tolerance when setting the timing and between the magnetos.
Cockney steve, there are material Reasons why valves don't burn in modern auto engines

Aussie Bob

13th Apr 2014, 19:57

No Hoper

13th Apr 2014, 20:14

Aussie Bob, from engine runs with a strobe light the most variation I have seen is about 1 to 2 degrees. Anymore was reason to suspect the initial setup or integrity of the system. If the timing is drifting back to TDC there is noticeable loss of power on the dyno run.

Jabawocky

13th Apr 2014, 20:46

no hoper
The initiall proposition was that the difference was in the order of 13 degrees

If you are reffering to me....that is simply wrong.

If I have somehow written that...I am perplexed. Having said that, set at 20 with one magneto setup, at idle you can get the occassional events like that. Typically is is more like a less than 5 degree lag. And a up to one degree variation on that or any point around there.

yr right

When will you answer all my questions so far? Or are you afraid to? They were not set up as traps. I would hat to be the Judge in a court case with you on the stand. Contempt of court perhaps?

How many CofA's I have done or been very involved in between 2-5. Not many. Some of you might ask what this has to do with the price of fish in Bondi ?

CASA approved training? You have got to be kidding. The answer is no and no thanks. But I would ask you to make contact with me so I can put you in touch with an extremely senior CASA employee, direct report to the DAS, and he can explain why the Authority has paid (I assume) for him to attend about 8 years ago and again last year.

Certain folk here were witness to this if you can't take my word for it. In fact I can think of 6, yes SIX people on pprune who can back that up. Do I need to name them all too?

And who needs it to be CASA approved? If you go to a Lycoming engine assembly school in PA do they need to be also?

Please do not book in for our class. The data would drive you over the edge.

UL........that is so true.

Creampuff

13th Apr 2014, 21:37

No Hoper (and others) please correct me if I am wrong, but say you set the static timing carefully to 20 degrees before TDC.

When the engine is running at around 2500 RPM, the actual timing will be around 12 degrees BTC?Yes – ‘ish’, on bog standard piston aero engines. The static timing depends on the specific engine model – some 22, some 24 for example. The amount of delay between the points physically opening at e.g. 22 and 24 BTDC and the spark happening is in the order of half a dozen to a dozen degrees, depending mainly on engine RPM.

The kind of timing referred to by No Hoper – using a strobe light – has its own built in delays. To put this another way around, the strobe does not flash the instant the points physically open. Often the strobe flash is triggered by the spark itself by a sensor on the spark lead, and the timing mark has been marked based on that assumption.

But I’ve had an awful revelation. I’ve just looked at the POH for one of the aircraft I usually fly, and have realised there is no procedure for descent! That is, it doesn’t say lower the nose or pull the power or anything else about how to get from cruise altitude to terra firma. What will I do? :eek:

Aussie Bob

13th Apr 2014, 21:38

Thanks no hoper :ok:

QFF

13th Apr 2014, 21:56

A comment on POHs in the GA world, if I may.John, I always thought POHs were were written by the marketing department. Now you are suggesting lawyers were involved.

What is the world coming to? Soon they'll be asking pilots and engineers to write them next....:}

Jabawocky

13th Apr 2014, 22:08

POTY by Creampuff;
But I’ve had an awful revelation. I’ve just looked at the POH for one of the aircraft I usually fly, and have realised there is no procedure for descent! That is, it doesn’t say lower the nose or pull the power or anything else about how to get from cruise altitude to terra firma. What will I do?

The less it says the more it tells you. Like Leadie's Boeing examples. Unfortunately most people be they pilots or LAME's are not critical thinkers.

yr right

13th Apr 2014, 22:13

Jaba
I asked about CofA for one particular reason. The CofA among many things is also a document chasseing exercise . Now one of the documents that has to be done is the POH, it has to show all areas of the aircraft performance in regards to any additional modifications that may incur engine airframe avionics fuel systems etc.
It is a legally binding document.

Now there is a big difference between static timing and the losses that you have said, a small loose is is explainable but the looses you have quoted arnt.also are your dyno models simulated ie computer based or actual runs with a hard full noise engine,

now a question was ask about automotive engines and why the don't burn out valves well there are few reason's one the size of a cly volume for a start now electronics that monitor the engine at incredible speeds, but the main reason correct me if im wrong and im sure you will is that air is quite an inefficient way of cooling as compared to a water based cooling system where you have the heat removed from the valve areas with 100 precent contact of the fluid surface to the substrate which it flows over, now also the main reason that you have forgotten is we gone away from 2,3, to 4,5,6,7,8, and now to 9 speed transmissions to allow the engine to run at its most efficient rpm range

Now Jaba
Your not Casa approved you not running a Casa approved course. Im sorry but that tells myself and I bet others quite a lot as well. (no personal attack here at all)
You see as a LAME I cant do a PT6or any other course for that matter or do a course any were I wish, if its not on the approved list it is not recognised at all despite having spent thousands of dollars on it.
This not only give credibility to that approved course but also shows they have met a standard.

I will also tell you I am also hold trend qualification and I am approved to read the data and act on it.

Cheers

yr right

13th Apr 2014, 22:20

mmm electricity stuff travels and the speed of light and the speed of light must travel at the speed of light or close to it so there for the rotating mass of an engine travailing at 2500 rpm must be moving at faster than the speed of light or fuc& we on to something here.

cheers

wishiwasupthere

13th Apr 2014, 23:04

No Hoper

14th Apr 2014, 00:11

Creampuff, not on my engines. The same timing marks are used for static and dynamic.

Jabawocky

14th Apr 2014, 00:19

yr right
Jaba
I asked about CofA for one particular reason. The CofA among many things is also a document chasseing exercise .

Absolutely, :ok: , and I am involved in a round about way in delivering a CASA approved training module that teaches EXACTLY that.

Now one of the documents that has to be done is the POH, it has to show all areas of the aircraft performance in regards to any additional modifications that may incur engine airframe avionics fuel systems etc.
It is a legally binding document.

So in that case the POH Creamie describes above is creating thousands of illegal descents and landings????

How many have you written? Have you had a few moments to reflest on Mr Deakins comments through this thread. He at least has written a few.

Now there is a big difference between static timing and the losses that you have said, a small loose is is explainable but the looses you have quoted arnt.also are your dyno models simulated ie computer based or actual runs with a hard full noise engine,
I think you would ask a different question had you spent even just a few minutes watching this for real. I am quoting you from HARD DATA, REAL ENGINE RUNS with real engines and no computer modelling involved. You would enjoy it, it would be very confronting, uncomfortable and challenging. The opportunity I extended to you to see it still exists, although I would need a strong curtailing of your present attitude though, unlearning and relearning takes a preparedness of the mind to accept that what we knew to be true is not. Just like the folk who thought the earth was flat. Very difficult to accept at first when all you knew was proven to be different.

Air cooled Vs water cooled is another kettle of fish....we should save that for face to face discussion. Or at least when I have a few hours.

Your not Casa approved you not running a Casa approved course. Im sorry but that tells myself and I bet others quite a lot as well. (no personal attack here at all)
You see as a LAME I cant do a PT6or any other course for that matter or do a course any were I wish, if its not on the approved list it is not recognised at all despite having spent thousands of dollars on it.
This not only give credibility to that approved course but also shows they have met a standard.

It tells me a lot too. It tells me that all the LAME's many of whom you know and respect apparently are wrong and foolish. So did you ever call Mr Bowden, Paynter or Denyer? How about you PM me your email address and phone number and I will put you in touch with the CASA folk (current and past) who have attended and ask them. You might find that educational as well.

I do not know how much more I can do.

I think it is fair to say you are a diligent hard working and passionate man with many many years of experience. But there is scope out there for more learning. I have found the more I know.....the more I want & need to know, and there is so much more to know. I know realise how little I do know. :sad:

mmm electricity stuff travels and the speed of light and the speed of light must travel at the speed of light or close to it so there for the rotating mass of an engine travailing at 2500 rpm must be moving at faster than the speed of light or

Yes it does, once the electron flow starts this is true, it is the triggering of this that has the delay. If you take a wing on a B747 and examine the spars and maybe pick up a section of spar, it will be very strong and sturdy. So much so despite all your strength, you can't make it twist or deflect, but somehow when you taxi out of Paine Field in Everett WA the wings are bouncing up and down like a piece of rubber. And worse as the aircraft lifts off :eek: I think you get my point. :ok: Have you ever seen the loads on a crankshaft? Again, eye opening stuff.

Creampuff

14th Apr 2014, 00:20

Let’s say a propeller is being directly driven by a crankshaft is rotating at 2,700 revolutions per minute.

That is 45 revolutions per second.

That is 16,200 degrees per second.

That is 16.2 degrees per millisecond.

That is 8.1 degrees per 0.5 milliseconds.

(For yr right, that’s one half of one thousandth of a second for the crankshaft to rotate 8.1 degrees.)

When the mechanical points open in that steam driven magneto, the spark does not happen instantaneously. It takes time for the secondary to build up to a sufficient voltage to cause a spark. How long it takes from the points opening to the spark actually varies from cycle to cycle. The crank’s twisting and the fuel air charge is slightly different each time, but all it takes is a delay of one half of one thousandth of a second and the crank’s already rotated 8.1 degrees. Sometimes it will be quicker and sometimes it will be slower, but the laws of physics dictate that it’s never instantaneous with the opening of the points (except when the static timing is being set up and the crank isn’t rotating).

NH: Please state, precisely, the kind of ignition system and procedure for setting static and dynamic timing: That is, what test or other equipment you connect, where, and what you are measuring. :ok:

yr right

14th Apr 2014, 00:27

It was written like that for a reason
Cheers

Old Akro

14th Apr 2014, 00:49

The same timing marks are used for static and dynamic.

I haven't done the timing on an aircraft, but I still own a couple of vehicles with points. I think the same issues apply between distributors on cars and magnetos in aircraft.

Static timing is a very sensitive thing, heavily reliant on technique. It is affected by the surface condition of the points. Unless they are new with perfect surfaces, the actual point of make and break varies depending on where the points meet. This moves around on the surface of the points with each make/break by maybe 0.5mm. If there is any surface pitting from spark erosion it quickly becomes unworkable. Also the shaft clearance has a significant effect. Any shaft "slop" will result in variation / lack of precision of timing because it moves the cam position. Any wear in the wear block of the points will similarly cause slight differences as the path it traces on the cam varies slightly. During the timing process the engine can never be rotated backwards - even a little - because it changes the backlash in all the gears and things. There is significant hysteresis in the system. I'd be doing something like 5 readings to look for the spread.

Dynamic timing generally gets a different reading. I've never thought deeply about it, but I guess centripital force plays a role in changing the point behaviour. And rotating gears (even straight cut) will provide some end load to the shaft which will change the cam / rubbing block position a bit. TDC itself probably varies a little as the crank moves around as hydrodynamic lubrication takes effect and lifts the crank off the bearing surface. And the conrod / piston assembly stretches a little. On a car, the only time I would ever use static timing is after a rebuild for its first start.

If you were really serious, you'd check the TDC mark. These can be out a couple of degrees. Especially if there has been a replacement or ground crank.

And its worth thinking about the accuracy of the measurement devices. I would have thought that +/- 1 deg would be the very best you could hope for with the various mechanical measuring devices that are commonly used. For race engines its common to use engineers protractors (as in drawing board type ones). As soon as you see a printed / stamped scale on anything you can assume an accuracy of marking of +/- 1mm. I wouldn't have huge confidence in the aviation ones I've seen. And as for the "flower pot" arrangement!

Creampuff

14th Apr 2014, 02:14

I think the same issues apply between distributors on cars and magnetos in aircraft.But note: Lots of old automotive engines have centrifugal advance mechanisms that automatically advance the timing in proportion to the RPM, with the static timing set up for ease of starting.

Most bog standard piston aero engines don’t have mechanisms that automatically advance/retard the timing in proportion to RPM. The static timing is fixed so that the actual timing is best at higher RPM, and is artificially retarded for start by an impulse coupling. (There are also fancy ‘shower of sparks’ starting systems for some aero engines, but those have an extra set of points – called, you guessed it: the retard points/breaker - in the magneto and different starter/mag switch configuration.)

yr right

14th Apr 2014, 02:17

43Inches

14th Apr 2014, 02:26

This is not about aircraft falling from the skies rather reducing the cost of maintenance.

A lot of the decline of GA in the last 15 years has been due to cost of operation. I was directly involved in a company that collapsed due to the weight of cost increase on it's fleet of ageing aircraft. If the company had been smart with it's operations earlier and introduced more trend based maintenance and operational procedures it may have maintained a cost advantage over it's competitors, maintained it's customer base and maybe still be going today. This was seen as an additional cost rather than smart investment. Instead we just flew things to time limits or when they broke and didn't look into why. The manufacturers time limits, operating techniques etc... are all based on a conservative average of what they think the machine will be exposed to. We had the chance to set up a maintenance program and operating procedures for our fleet that was specific to our needs, but it was deemed too hard.

Walter Atkinson

14th Apr 2014, 02:48

Re: Timing set and ACTUAL timing of the spark event.

In the TIO-540 J2BD:
When the timing is set properly to 20 degrees btdc, the ACTUAL spark event occurs at about 16d BTDC NOT at the set 20 degrees. This is by measurement.

I am certain that Lyoming is not aware of this and did not "design" for it.

This has nothing to do with all of the reasons discussed in this thread.

BTW, it saves the engine to not fire at the timing mark. If the sparks occurred at 20d btdc, the engine would suffer heavy detonation.

As for CASA approval for the APS class, we have made no attempt to ask them for "approval." The APS class was approved by the FAA for 16 hours of A&P (LAME) annual certification the first year it was presented. The FAA thinks it's OK!

As for Yr Right, I wish he and others like him (there are a few others, ya know?) would become better informed. They and their clients would be the better for it. OTOH, there are none so blind as those who will not see.

Brian Abraham

14th Apr 2014, 03:16

Walter, as you may have seen earlier mention was made of the legality of LOP.

For example, the Cessna 207 POH has the statement in normal procedures section "Operation on the lean side of peak is not approved".

We all know how litigious the USA system is, so how does LOP sit in the legal framework, and with the FAA?

In Australia we have a regulation CAR 138 which states,

Pilot to comply with requirements, etc of aircraft’s flight manual, etc
(1) If a flight manual has been issued for an Australian aircraft, the pilot in command of the aircraft must comply with a requirement, instruction, procedure or limitation concerning the operation of the aircraft that is set out in the manual.
Penalty: 50 penalty units.
(2) If a flight manual has not been issued for an Australian aircraft and, under the relevant airworthiness standards for the aircraft, the information and instructions that would otherwise be contained in an aircraft’s flight manual are to be displayed either wholly on a placard, or partly on a placard and partly in another document, the pilot in command of the aircraft must comply with a requirement, instruction, procedure or limitation concerning the operation of the aircraft that is set out:
(a) on the placard; or
(b) on the placard or in the other document.
Penalty: 50 penalty units.
(3) An offence against subregulation (1) or (2) is an offence of strict liability.On the face of it I'm assuming that LOP can not be supported legally in Australia, unless specific mention is made approving its use, as is the case with the Chieftain.

Thoughts?

BTW I do support the LOP theory of operation - not a piston driver though.

Jabawocky

14th Apr 2014, 03:35

We'll I can say I'm fully aware of forces on an airframe and the internals of an engine.
I've done and been involed with some serious design work in the area of stress.

Now I don't need to be unlearned if we had serious problem with aircraft maintenance aircraft would be falling out of the sky.

I have a MUCH better idea.

Seeing you are so better prepared for this than I will ever be, I want to offer you the spare microphone kit and you can take the 2.5 days (about 19 hours full on) training course for me and Andrew Denyer and I will sit at the back of the class.

What is more if you do this I bet all the folk on this thread will chip in for George Braly to fly out from Ada OK and sit down the back with us. We will then ask all the heckling questions you can handle. If you think I am easy to blow off, try George. :}

I reckon Walter would not miss the show either!

No Hoper

14th Apr 2014, 03:42

Creampuff, DDI to find top dead centre of piston, degree wheel on crankshaft, to confirm timing mark in relation to top dead centre of compression stroke.
Now working with electronic distributed, set up on No1 firing and fit using degree wheel to locate 12 degrees before TDC.
Start engine and confirm dynamic is same. Using electronic timing llIghr at No1 lead. I have vacuum advance locked out, adjust timing to best vacuum at idle. Timing all in by about 3200 RPM of 24.- 26 degrees
That's my 302 Windsor

Avgas172

14th Apr 2014, 03:44

Now I don't need to be unlearned if we had serious problem with aircraft maintenance aircraft would be falling out of the sky. Ethier which I don't see what happening.

And yet we have the SIDS program? :hmm:

Creampuff

14th Apr 2014, 03:56

In the TIO-540 J2BD:

When the timing is set properly to 20 degrees btdc, the ACTUAL spark event occurs at about 16d BTDC NOT at the set 20 degrees. This is by measurement.

I am certain that Lyoming is not aware of this and did not "design" for it.

This has nothing to do with all of the reasons discussed in this thread.

BTW, it saves the engine to not fire at the timing mark. If the sparks occurred at 20d btdc, the engine would suffer heavy detonation. Now you have me very intrigued.

Does the measured delta between the static and actual vary with RPM?

When you say “this” has nothing do with all of the reasons discussed in this thread, are you referring to the delta between static and actual, or Lycoming’s lack of awareness?

If you are referring to the delta, to what do you attribute the delta if not the rotation of the crankshaft during the short period between points opening and the voltage in the secondary building sufficiently to cause the spark? (4 degrees at 2700 RPM takes only 0.25 milliseconds….)

(NH: Sorry, you’ve lost me. “Set up on No1 firing and fit using degree wheel to locate 12 degrees before TDC. … Timing all in by about 3200 RPM of 24. – 26 degrees.” Where does the 12 come in? If static’s the same as actual and the vacuum advance is locked out, the RPM shouldn’t make any difference… :confused:)

mcgrath50

14th Apr 2014, 05:08

For example, the Cessna 207 POH has the statement in normal procedures section "Operation on the lean side of peak is not approved

This is interesting legally. Although not in the limitations section the words "not approved" seem worrying.

No Hoper

14th Apr 2014, 05:15

Creampuff, only vacuum Module locked out still have centrifugal advance.

yr right

14th Apr 2014, 05:16

SIDS program has nothing to do with the engineer. It's a development of what they have learnt over the years to cya themself. Further more as lame we like to look at stuff people like your self scream blue murder I'm not paying for that. At least this gives us reasons to follow up now with being told we cu$&s. Plus you see there is reporting also back to manufactures when we find stuff and they even buy back old aircraft and then proceed to inspect them and test to destruction May be you could offer your aircraft to them.

Cheers

yr right

14th Apr 2014, 05:32

Jaba
Nah I don't need to stand up on a soap box and talk jibberish sorry. If you and your course were Casa approved then I may be interested. But as they are not dosent really do it for me sorry. I'll just learn my science the old way like I is been doing.
But hey thanx for the offer but.
Cheers

Whoops but has anyone still know how to test your fuel system quickly.

Aussie Bob

14th Apr 2014, 05:47

yr right, you seem to lump all aircraft owners into the same bag. Sorry, I know quite a few, myself included that want the extra yards spent inspecting and looking. I also replace the "will last another 100 hours" components on the spot. In short, any recommendation my LAME makes to me I follow through on.

I also educate myself by spending big on courses like Jabber offers because i like to understand what goes on.

I also tend to think you look at names on this forum like "Creampuff" and judge the character by his "name". Long term readers of this forum know creampuffs and their like write articulate accurate facts and will admit when wrong. Although a self confessed resident of The States, Creampuff even seems to spare us American English.

Creampuff (and others including you Mr. Right), I thank you for your inputs.

RadioSaigon

14th Apr 2014, 05:53

Nah I don't need to stand up on a soap box and talk jibberish sorry...

yeah, right...

A Squared

14th Apr 2014, 06:02

Nah I don't need to stand up on a soap box and talk jibberish sorry.

yeah, right...

A masterpiece of unintended irony, that.

A Squared

14th Apr 2014, 06:07

Your not Casa approved you not running a Casa approved course. Im sorry but that tells myself and I bet others quite a lot as well.

Galileo's course material wasn't Vatican approved either.

Jabawocky

14th Apr 2014, 06:36

I guess you missed this piece further up the page. Or deemed a CASA approval that would not exist or be worth having is far superior.
:rolleyes:
The APS class was approved by the FAA for 16 hours of A&P (LAME) annual certification the first year it was presented. The FAA thinks it's OK!

Still not one answer to a question posed or a link to any "public record" for the benefit of educating me.

I am impressed to say the least.

Creampuff

14th Apr 2014, 06:42

No Hoper said:

… only vacuum Module locked out still have centrifugal advance.I’m therefore not sure that the way in which static timing is set and dynamic timing is measured on that engine has much application to a bog standard piston aero engine.

A bog standard piston aero engine has mechanically fixed timing. There is no centrifugal (or vacuum) advance. (Impulse couplings on magnetos are a centrifugally-disabled retarding mechanism, to assist starting only.)

That’s one of the reasons it’s good to know how to use the RPM, mixture and throttle controls (mainly RPM and mixture) to move the PPP within a fairly small but operationally important range after TDC, on piston aero engines.

Oracle1

14th Apr 2014, 07:01

Gentleman it is clear we are wasting our time with trying to educate him
and further attempts will only lead to frustration.

Dont feed the Troll!

http://i875.photobucket.com/albums/ab320/oracle1_2009/tumblr_l2a1omvNhD1qzp0dfo1_500.jpg (http://s875.photobucket.com/user/oracle1_2009/media/tumblr_l2a1omvNhD1qzp0dfo1_500.jpg.html)

No Hoper

14th Apr 2014, 07:07

Creampuff, fair call but the check for static and dynamic timing is the same for bog standard aero engine and am still researching the implications of the variance that you have found in your research. When I get back to civilization I will talk to the aero engine gurus and see what it all means.

Hempy

14th Apr 2014, 07:26

Dont feed the Troll!

Nah, I disagree. I reckon he's about to go postal shortly, will make for entertaining viewing in a train crash sort of way. Off cors it dosent help that yu haveto run evry post thru a trans laotr but that haf the fun!

yr right

14th Apr 2014, 08:17

Nah I'm not postal. I've got runs on the board what have you all got ?
Cheers

Mick Stuped

14th Apr 2014, 08:34

43inches
Couldn't agree more. Any operation still in business has to look at every avenue to survive.

The old adage of run smarter not faster applies. A little education and keeping up with maintenance trends can help make better informed decisions and a fuller understanding of both planned and past unplanned maintenance can make for a safer operation.

Its the lot of little things that save big time and money.

Trend monitoring now using downloaded EDM data can help find little problems way before they raise their head at some isolated strip and become a big problem.

What is the option to try and maintain a profit? The only option is to reduce pilots wages. This is always the option of the uneducated, unscrupulous and the cowboy operations and has bought a bad reputations down on all of us operators that, like us, look upon our staff as family and the most important asset in the company. We pride ourselves on always paying award wages, because we have all come up the hard way of no money but lots of passion. Happy well paid, good trained pilots save lives and build companies.

I think the APS course or simular should be mandatory for every young budding pilot/LAME and CFI in Australia nothing to do with LOP but just to get a better understanding of what's under the cowls and how to read and understand what the EDM is telling them in front of them.

I for one, if I read on a CV from a pilot that they had attended a engine management course run by a company with a reputation as the APS has then they would certainly get a call back. Wouldn't guarantee a job but certainly a second look.

Please don't think I am in anyway that I am part of APS or get any kickbacks. I attended a course some years ago when new engine management was first being discussed in Australia through the CPA and what I learnt from them, and then the next 8 or so years of trying to put some of AAAHA moments together that came as revelations of running a steady growing aviation business.

43Inches

14th Apr 2014, 09:12

Not involved in APS either, don't know what they do but it sounds like they're on the right track. What I like about their stance appears to be dragging aircraft maintenance and operational theory out of the dark ages. To a point almost where most other modern industries have been for years. From, don't ask just do it this way to think about what you are doing and how can it be done better.

If they were around when I was flying pistons I'd probably get along and see.

Occasionally we had a great engineer or pilot who would question the way things were and offer a suggestion on how to improve things from experience or just analytical toying with the thing. These ideas solved a few very small but expensive problems with our aircraft that you won't find in the manufacturers books. One place I worked had almost 100 CASA EOs on an engine type to try and raise reliability, it mostly worked, but the aircraft and engine manufacturer didn't want to have anything to do with it. As the good guys left the problems returned as things filtered back to book fixes (or worse, the old, this worked on a Cessna so I'll do it to your Piper).

If we got all these things back into a system of maintenance, given time it would have saved enormous amounts of cash. You'd be surprised at the amount of $10 fixes that could save thousands, but that's what preventative maintenance is about. There's also a lot of aircraft maintenance that is not require that could be delayed based on good trending and monitoring.

yr right

14th Apr 2014, 09:16

Galileo's course material wasn't Vatican approved either.

correct but a lot of them had 1st class seat at the bbq.

now the difference between myself and most you out there is I place my name my lic on a document that is certifying that it is true and correct and I am liable in a court of law if I have made a mistake. Big difference to what you all I bet.

ive asked some basic things here that you all cant answer correctly. You seam to think you know but you have been in correct.

you can say what you wish I really don't care I get my PM in and they say the same as what I do.

If you are running a course and it not certified it proves a lot. Now ive learnt a lot over the years and am still learning I understand how and engine works also how an airframe works and the interface between them. I am not blind to new things but what I am amazed at is you think LOP is new.
For some of you that don't have an engineering back ground go do the course it may be a wake up. But don't expect me too and if I don't im dosent mean im backwards, remember I see what happens and engines don't lie to me ive been doing this to long now.
Jaba ive said im not telling you what has happened in court, there are people that know me and know what happened so lets just leave it at the hey.
And if you wont me to write technical I can I just choose not too, so who out there had to write technical information them self and had to submit it to a court ?

Chers

yr right

14th Apr 2014, 09:23

but that's what preventative maintenance is about. There's also a lot of aircraft maintenance that is not require that could be delayed based on good trending and monitoring.

Um I think I said that way back when. trend trend and more trend. Now when you aircraft is down it cost more to send someone out to fix it that is an additional cost. Most reasonable places do trend we use to trend then replace ,are break downs where minimal.

trending will save you more than LOP every day of the week. I keep saying fuel is the cheapest thing you can put in you aircraft.

Cheers

No Hoper

14th Apr 2014, 09:29

Those that accuse Yr Right of being a troll need to stop being knobs and contribute to the discussion theyselves.
The man has contributed since early in the thread, which is contrary to the meaning of troll. You make yourself troll by posting specifically to insult the man.
If the discussion is too technical for you go over to the Truss thread and have happy ending with your fellow knobs there, creampuff and leadsled excepted

yr right

14th Apr 2014, 09:36

Cheers No Hooper
I will say this again I was ask my opion on LOP. I gave it ill stand by it. Fuel is cheap.
And ive noticed you all went a little quite on the exhaust valve in a car what sorry not technical enough,
Cheers

43Inches

14th Apr 2014, 09:49

trending will save you more than LOP every day of the week. I keep saying fuel is the cheapest thing you can put in you aircraft.

Trending is a maintenance practice as part of a larger system of maintenance. Running LOP is an operational practice as part of a larger operating procedure, the two would be part of a larger operating philosophy that would put them hand in hand to reduce costs in an operation, that is if you agree with LOP ops and know how to do it properly. If LOP was damaging your operation trends would show it up.

To know whether LOP is good or bad you would need to trend the outcome over time and monitor the condition of affected parts. It sound like the APS guys have good data on the subject, good data can be approved and turned into operational practice and away you go.

Creampuff

14th Apr 2014, 10:21

And here we encounter the bitter-sweet dilemma of witnessing endangered species on the brink of extinction. On one hand: respect for the history and vast experience; on the other: exasperation at the dinosaur stupidity.

In circumstances like these I'm reminded of the counsel of a genuinely wise engineer: Creampuff, you can lead a horse to water, but you don't have to suck through its ar*e to make it drink.

Good luck yr right. :ok: (Seriously: good luck in your retirement. You've earned it.)

yr right

14th Apr 2014, 10:34

We'll I'm sure I'll be fine changing dead cly.
Cheers

Mick Stuped

14th Apr 2014, 10:35

43inchs
You hit the nail on the head. LOP operated correctly in conjunction with a good EDM and well trained pilots will save not only maintiance costs, extend cylinder/valve life but will also save the price of an engine in its life in fuel savings alone.

All up we may have trended data from EDM's saved over maybe 10,000 hours and 6 to 7 years on a range of engines.
It works for us the data proves it, our maintiance bills prove it.

My concern is that in desperation to stay in bussiness a lot of our competion will try and go LOP without management having the knowledge or understanding or training of how to run a fleet LOP and get the most from the data and review their pilots operations to make sure their engines are happy. If not Yr right will keep seeing damage from LOP done wrong.

I like Yr right do hope that it doesn't become to popular as I like to have slight competive edge on the opposition.:oh:

cockney steve

14th Apr 2014, 10:49

Oh, Jeez, Yr. Right, NOBODY has suggested that LOP is "new"

People have spent a lot of time and effort, trying to help you understand just how important a correct mixture is.

I flew a bit with a friend in an Aeronca Chief. NO MIXTURE CONTROL!!!
Armstrong starting, an Icom handheld and a very basic panel.

That aeroplane ran rich on the ground......it failed to climb above 10,000 feet because the engine was choking-up. All that excess energy was going out of the exhaust as soot.

In an aircraft with a mixture control, you have the ability to reduce the fuel -to air mixture, for a "perfect burn"-within the limitations of fixed valve and ignition timing and compression ratio.

What everybody has been trying to explain, is that, whilst excessively rich mixt. CAN have a beneficial cooling effect. there is a band of ratios from "rich through "weak" where detonation is likely to be prevalant.
Go rich of the "danger band" and you'll waste fuel and foul plugs.

Go weak of the "danger band" and you'll lose power , as cylinders will either stop firing or the mix is simply too weak to produce power.

I'd suggest all your duff "cly's" (Why don't you write CYL's as an abbreviation? ) have been run in the "danger area"

It's just a shame that the laws of physics have shoved this detonation area bang in the middle of the combustible range of mixture -ratios.

Fed up now, the water's right there, your choice wether to drink it free of charge..... If I lived in Aus, I'd be tempted by that course and i'm neither a LAME or Pilot.
You see, Yr. Right, you really have no idea who is behind the "handles"
But it's pretty obvious to me , that some very well-qualified, literate and intelligent engineers, with real, hands-on experience, have been trying to help you understand this method of engine operation.

Some years ago, a UK company prodiuced a glass-insulator spark plug (Gunson's Colourtune)...It enabled you to actually watch the combustion-chamber burn and set idle mix accordingly....unfortunately it was not robust enough, and lacked the heat-range, to run under load on a Dyno.

yr right

14th Apr 2014, 11:02

Mick.
As you said is correct. The problems related to lop can be very devastating with costs of damage. As I've said you trend. That's a big difference. But for the average joe it's a dangous playing field. For a ga guy that runs under a 100 hours a year fuel is cheap. This is not the first time I've have. One across this. Experience tells me things in advance. As I said I sign my own work and stand by it. I spent 15 k on repairs today on two engines less than 300 hours old. Try explaining that. But we run a safe fleet and a extremly reliable fleet. And we don't lop.
Trend trend and trend it's more important than lop. Fuel is cheap. And I'm no dinosaur we'll not yet anyway. And anyway I've got turbines as we'll so I'll be right. And I do give you congrats on your org and btw I have zero idea who you are or where you are.
Lames are the last line of defence in safety. Learning to say NO is the hardest thing I have ever had to say. I did and that's what makes me a better engineer.
Cheers

cockney steve

14th Apr 2014, 11:08

Blimey! this thread has been busy whilst I was replying...
I'd suggest that the lack of burnt exhaust valves..... YOU AGREE, Yr. Right? There are very few nowadays?

Is due to the very weak mixtures now prevalant...= lower temperatures. (Agreed, improved materials do have a part to play)

Remind me again, how do you establish the correct ratio?.....OH!YES! you lean so the cylinder head temperature is a number of degrees below the peak temperature a cylinder will develop.

Maybe , in due course, fully automatic, feedback-loop controlled ignition and fuel systems will become certified and normal for Aviation Piston Ops. meanwhile, like a 1930's car, the Chauffeur will just have to develop a "feel" for the engine and adjust the controls available , for best performance.

yr right

14th Apr 2014, 11:11

Um I never said don't lean. I have just said don't do lop. That's a big difference. Same as wayalla accident. You all said it was rich enough clearly it wasn't as it failed. The engine took off with no problem it would have been in full rich. The crank didn't fail. It's an important lesson that you will not admit to. People life's where lost. At the end off the day it's not my decession to run lop and I won't tell anyone to do it. That's not my job. If ask like I was here I'll say what I have to say. Like I said I sign my name against what I do. None off you do. That's not brave. If I come across dead cly etc it gets fixed that's my job.
Cheers

Ultralights

14th Apr 2014, 11:16

Yr Right Nah I'm not postal. I've got runs on the board what have you all got ?

I know for a fact, as i have met some here you are arguing with, how many runs they have on the board, and they are quite significant. and myself, you might be surprised..

so just what are the runs you have on the board?, so i can make an informed decision on how to interoperate what you have been telling us.

yr right

14th Apr 2014, 11:17

Please don't tell me what I may or may not know. Because what you just said about me is prune ****e if you can explain to me how detenation burns an exhaust valve cause I'm most interested in that.
Cheers

yr right

14th Apr 2014, 11:33

Quick quiz. What controls the cooling air over an air cooled Areo engine. By that I don't mean the cowl flaps
Cheers

Ultralights

14th Apr 2014, 11:38

I have my ideas on burnt exhaust valves, based on the evidence i have seen, data from real time engine runs in various conditions, talking to, and asking question to people with vastly more experience operating all types of piston engines, and from the engines of my aircraft, (which, have never burnt a valve, or shown any evidence of damage due to mixture variability) but you are the LAME, what are your suggestions on what causes burnt valves?

Ultralights

14th Apr 2014, 11:39

Quick quiz. What controls the cooling air over an air cooled Areo engine. By that I don't mean the cowl flaps
Cheers

Differential pressure.

yr right

14th Apr 2014, 11:59

Diff px yes but what controls it.
By runs on the board what I've done where I've done it. And by signing my own work and that of others.
Cheers

Ultralights

14th Apr 2014, 12:25

Quote:
Originally Posted by yr right
Nah I don't need to stand up on a soap box and talk jibberish sorry...

yeah, right..

Post of the year in the Thread of the year! :ok:

Jabawocky

14th Apr 2014, 12:34

I think he means exit air and lower deck pressure but just like he keeps talking up his enormous qualities, he never backs it up with any substance.

He still has not answered any of my questions, been dismissive of some very high calibre folk, one of whom I believe is a current customer and in shock at the attitude.

So do not expect much sense UL. Why don't you ask him about how much air passes through the engine and where the rest actually goes?

I would love to see an answer to that. Be funny if it was correct for a change. And Walter or John do not give it away just yet (big hint Walter participated in STC tests that blew most in the game away). And for the well read folk just hold back for a bit.

OZBUSDRIVER

14th Apr 2014, 12:54

Yr right...you are starting to sound like you haven't graduated from the school yard skite.

Lean of Peak ops, as Deakin put it, is something that was standard ops on the big Wrights but with the advent of the jet age was just plain forgotten about. Now, it isn't re-inventing the wheel, it is just learning to walk all over again.

My pet tech advancement to watch is replacing AVGAS or using JET A in recipe. It may well cause the reintroduction of another old technology with a new metallurgical spin...turbo compounding! Plus LOP equals a better performing engine in the FL200 to 300s more efficiently than turboprops. All old technology.

yr right

14th Apr 2014, 12:56

Oh Jaba must have hit a nerve have I. You gotten a little nasty. Oh a costumer of mine mmm do tell. Like I said I back my substance every day via a signing legal documents every day. You don't. Big difference.
Sorry should not react like that but however it was called for. Like I said i not making charging or anything from this post. You say data data data. I say I see see see but you don't take that on board. You say it's some thing else. What you think we so stupid not to check every thing that's going on. When we have a problem we check everything it's our job. You were extremly reluctant to say yes if the engine had full fuel it would not fail.

Now you Arnt casa approved nor is your course but you say that is ok. Mmm sorry I and others don't think so. Get approval and set the record straight the. You may have some credabilly cause not only in my eyes but many others you don't have with out approvals.

Training orgs can't train aircraft appentises with out casa approval. Why should you be different if you are going to make claims about how we'll you train and have people pay get an accreditation. Now if you are training people that work I. The oil gas industry and they do an audit I can assure you that they will every not use or demand that it is not used. Chances are they won't use piston engine aircraft but they may.
You say you really can go against the PoH we'll you can't. And as I've said you left a big hole for yourself.
But any way
Cheers

yr right

14th Apr 2014, 13:00

Oh sorry when have I ever talked my self up. The only time I say stuff about myself is after I've been asked. As aster of interest every been to court every had a death on your mind I guessing neither to both we'll it's both to me.
Cheers

Walter Atkinson

14th Apr 2014, 13:03

Operations of any type are only prohibited legally if the prohibition is in the LIMITATIONS section of the POH. This topic came up in all three of the APS classes I have taught in Australia and the CASA representatives present agreed that operations on the lean side of peak were legal.

If one reads the POH more carefully, the text may say one thing and the engineering graphs something else, fully in contradiction with itself!

For example, the Malibu PROHIBITS ROP operation in cruise in the LIMITATIONS section. It is illegal to operate that aircraft ROP.

In years past, CASA has had a very hard-line approach to strictly following the POH and it has created some problems for them. For example, if the POH said that the oil should be changed at 50 hours and if you did so at 25 hours CASA considered that operating outside the POH. That is a silly notion. One does better than the POH recommendation and could be violated?? Since attending the first APS class in Sydney 5 or 6 years ago, they have significantly softened their stance on such issues, including understanding that the POH is only regulatory if the recommendation is in the LIMITATIONS section. Otherwise, the "recommendations" found in POHs are simply that. At the last APS class in Brisbane, the CASA rep was very supportive of lOP ops… even in cases where POHs were "recommending against it" outside of the LIMITATIONS section.

yr right

14th Apr 2014, 13:18

its one thing to say that but the regs don't allow that. The poh is over ridden by the log book statement and the M/M. And the biggest problem is the AWI at each section have there own ideas and enforced them that way. If the poh doesn't say it you cant its very clear as someone posted earlier.

Ultralights

14th Apr 2014, 13:24

I maintain aircraft,every type, even rotary wing, and I'm regularly sent on courses on the latest maintenance and engineering techniques, that have constantly evolved as new technology becomes available, and the changing techniques that come around from a better understanding of the processes and damage modes discovered from the use of newer technologies, yet through these evolving procedures, design and equipment, one thing remains the same, The aircraft themselves.

I personally would be very sceptical of any maintenance organisation that doesn't make an attempt to keep itself up to date with the advances made by new technologies, even if those technologies serve to confirm long lost knowledge of times past.

And yet, most of the recent courses attended have not been approved by CASA, and most likely never will be. But the new insights and skills will be applied to aircraft in Oz.

Walter Atkinson

14th Apr 2014, 13:26

My credentials:
ATP, CFII, MEI, A&P (LAME), 15 years of experience in the most advanced engine test facility in the world, extensive research on engine cooling, baffle design, I hold three US patents on inventions in the filed of aviation and I hold a doctorate. I have written expensively in refereed journals in two different scientific fields; one being aviation. I was asked by the FAA to review their aviation certification exam questions concerning engine management for accuracy and recommend appropriate changes.

Obviously, that pales in comparison to Yr Right's experience and credentials.

Yr Right, please explain in detail how the air moves under a cowl and is used to cool the engine (let's start with the conventional, top-down cooling arrangement before we move to the up-draft designs). Please include specifics of air flow; please include an estimate of the percentage of air entering the cowl which is used for cooling.

I anxiously await your explanation to clarify my understandings.

(Even though I hold a doctorate, please make an effort to describe this with words and in syntax which can be easily understood by a Yank like myself. I apologize; I have difficulty understanding the wording of many of your posts.)

In addition, it is worthwhile to remember that unless Sir Isaac Newton was wrong,, "the physics are everywhere the same." So, how data "looks" in Yr Right's shop must be the same as everywhere else, or there's a worm hole connecting his shop to a parallel, yet reversed universe.

yr right

14th Apr 2014, 13:34

good on you walter im pleased for you.
cheers

yr right

14th Apr 2014, 13:37

as for airflow though the cowl system I was refering to the exit is what controls the air flow you see most people don't know that cause we simple folk down here
Cheers

Jabawocky

14th Apr 2014, 13:38

Oh Jaba must have hit a nerve have I. You gotten a little nasty.

No, I have not gotten nasty. I have deliberately been consistent and persisteant and ultimately it has provoked the response by challenging you. And that is the best you can do.

My post said the following;

1. just like he keeps talking up his enormous qualities, he never backs it up with any substance. Ohh yes you do and no you never back anything up with anything more than rhetoric. - Thus far true.

Just go back through this post and answer my questions. I do believe I paid you the courtesy of doing this for all yours. But you seem to refuse to have the common decency to do the same. - Thus far true

2. been dismissive of some very high calibre folk - Thus far definitely true

3. one of whom I believe is a current customer and in shock at the attitude. - Not proven yet, but seems like it could be true. Not that it matters greatly. But you do seem edgey about it.

4. So do not expect much sense UL. Why don't you ask him about how much air passes through the engine and where the rest actually goes? - Thus far True (not expecting any sense) and how about another good question for you to not answer. You started the DP topic after all.

So where is there nasty in this? I just want you to pay me and others the same courtesy you demand.

You have not answered one question asked of you. Why? Is it beneath you or something, because that is the tone we are getting.

Oh sorry when have I ever talked my self up.
In just about every post, and when not doing that, doing it inversely by slagging off at those who we know are of high calibre. This says it all.

The oil gas industry and they do an audit I can assure you
Ohh yeah....I forgot to mention my wife. guess what she does for one of the three big ones. And guess what she calls the shots on for that big three O&G company? And funny....auditing of suppliers and their suppliers....and guess which fields of transportation she manages? She is generally a very pleasant lady to do business with but having been in engineering and more recently mining and O&G for 25 years she takes fools very seriously. I hope you understand that I know a little about this industry too. Not that it matters much.

So please stop treating us all with contempt. I am not getting nasty, but I will not be bullied by you.

Walter Atkinson

14th Apr 2014, 13:38

Since you are so pleased for me, would be polite enough to answer my question?

Please explain in detail how the air moves under a cowl and is used to cool the engine (let's start with the conventional, top-down cooling arrangement before we move to the up-draft designs). Please include specifics of air flow; please include an estimate of the percentage of air entering the cowl which is used for cooling.

Or, if you do not know the answer, please be polite enough to say so.

Your answer that the exit controls the airflow is woefully incomplete.

yr right

14th Apr 2014, 13:49

diff px in that the lower as in underneath has a lower px and thus air is drawn down to the point if you have a look at small Cessna cowl with out cowl flaps there is a little lip to create even more of a px drop.
next I don't bully anyone let alone your self.
and I can assure you are wrong about a client.
I have also said will not answer technical data I speak in general terms and I have a good reason for doing that.
And as for substance I do that every day with a pen
Cheers

Oracle1

14th Apr 2014, 14:01

diff px in that the lower as in underneath has a lower px and thus air is drawn down to the point if you have a look at small Cessna cowl with out cowl flaps there is a little lip to create even more of a px drop.

lets talk about ratios of inlet to outlet and relative density please, including compressibility and stagnation. What differential is required before we actually see useful flow?

I have also said will not answer technical data I speak in general terms and I have a good reason for doing that.

Only data counts. I am actually glad that you've stirred up the heavy hitters because I think we are about to see some information for free that cost a lot of coin to discover.

Walter could you please go back over this matter for me it is ages since I looked at this stuff, especially back flow

Ultralights

14th Apr 2014, 14:02

While studying the new pipistrel panthera, I noted NO lower air exit, none, it's completely flat under there.. Where it does exit is quite a brilliant method, something I was certain would have been tried in older aircraft (read all up until last year) Again, a solution only newer technology and data made possible.

mcgrath50

14th Apr 2014, 14:30

A little education and keeping up with maintenance trends...The only option is to reduce pilots wages. This is always the option of the uneducated, unscrupulous and the cowboy operations and has bought a bad reputations down on all of us operators

LOP operated correctly in conjunction with a good EDM and well trained pilots will save not only maintiance costs, extend cylinder/valve life but will also save the price of an engine in its life in fuel savings alone.

Mick,

I don't know who you are or where you operate but I hope one day I come across you resume in hand! Thanks for not being stuck in the 'bad old days'. I know there are many operators like you but there are also too many who don't believe in the science and don't think outside the old box.

Jaba et al.,

Keep up the good work of educating! Hopefully you keep running courses in Oz as I am saving to make it to one ASAP.

Ethel the Aardvark

14th Apr 2014, 15:19

Just read this from RAM aircraft co website in the USA.

RAM is aware that some aircraft engines are designed and have FAA approved procedures to operate at lean-of-peak settings, and RAM knows that there are advocates for LOP operations whenever balanced fuel nozzles are installed. RAM supports the installation of balanced or matched fuel flow nozzles, but does not, in fact cannot, condone or approve their use to operate an engine at an unapproved mixture setting. RAM’s position is that LOP is not suitable for all airplanes, engines, or pilots. A major engine manufacturer has made a point that it only takes a brief episode of mis-management to bring about deep internal damage, and they point out that pilots don’t always realize when it happens, since their engine continues to operate. They suggested that lean-of-peak can be akin to operating on the edge, and that doing so requires pilots to be very precise, have good instrumentation, and watch their engine mixture and throttle full time. RAM agrees.
RAM reminds pilots that mis-management at LOP settings can cause both dynamic stresses and thermal stresses that hammer main and rod bearings, burn pistons, burn valves, and cause cumulative exhaust system damage. RAM encourages pilots wishing RAM would recommend other than (ROP) rich-of-peak to research the numerous White Papers and Engine Manufacturer’s Publications addressing the advocacy issue of LOP vs. ROP. RAM reminds it’s customers and friends in General Aviation that mixture management of a turbocharged Cessna 414A at FL230 is more demanding than the mixture management required of a normally aspirated Cessna 210 at 9,500 feet. Again, RAM cannot recommend LOP operation for any aircraft piston engine not authorized to do so by its manufacturer or an appropriate FAA approved flight manual supplement (AFMS).

Seems to be a much more balanced argument.
Maybe the thread title should be changed again to " Everthing you wanted to know about engine management in the experimental category but was too afraid to ask".

gerry111

14th Apr 2014, 16:09

I recently had the absolute pleasure of taking my 84 year old Dad for about a two and a half hours GA flight, for the first time. The aircraft was a 1967 V35 Bonanza and my Captain was operating the Bo's IO520 LOP!:eek:

Perhaps doubly risky, yr right, as those V tails sure can be killers...

Thanks again, Creampuff!

jdeakin

14th Apr 2014, 16:20

Just read this from RAM aircraft co website in the USA.RAM builds fine engines, and does fine work.

But RAM remains the lone holdout on LOP operations, solely because of one man there, the owner, who has blocked all attempts to educate him, to show him data. Like "yr right," he simply refuses to listen. He has softened his stance a bit, he used to say "Warranty is void if operated LOP." Then it was "Warranty may be void, if operated LOP." Maybe he's dropped that language. To our knowledge he has never actually denied warranty because of LOP operation - perhaps because he's never recognized it!

"The Concert Pianist does not ask the fellow who tunes the piano for advice on how to play the piano." (Stuart Spindel)

The rest of the crew mostly admits it's a nutty policy, but he is very authoritarian.

LeadSled

14th Apr 2014, 16:59

If CASA has gone beyond this, it is a tribute to the remarkable institutional stupidity of that organization, amply and vividly demonstrated by the Whyalla Report. It needs to be changed. How to change is above my pay grade.

So please, do what you must to satisfy the morons who work there, but DON'T make the mistake of thinking they are right, when they are most definitely not in suggesting the "How to fly" text in the POH came down from Mt Sinai, along with the Ten Commandments. Folks,
I could not have said it better myself, Mr. John Deakin has very succinctly summarized CASA as an organisation. In my view, CASA's (and ATSB) technical competence has deteriorated since the era of the Whyalla accident.

yr right,
If you have any doubts about the accuracy of the above comments, I suggest you look at the last two ICAO audits of CASA, and their public results, or the results of the last two FAA audits. In polite language, they do tend to confirm Mr. Deakin's views.

I note you have still not answered very specific questions posed at post#315, as a result of your accusation. This being the case, I think we can safely assume no such regulations exist, despite your claims to the contrary.

The difference, legally, between you doing a Type course for an endorsement on your license being "CASA Approved" and the course under discussion here, is the latter does not result in any CASA action.

Obviously, you believe that "CASA Approved" is a bit like sprinkling holy water on the course, making the contents sacrosanct.. Some time ago, I attended part of a CASA Airworthiness Delegates Initial and Refresher, for both CASA AWIs and industry delegates. Some aspects of the course were staggeringly legally incorrect, particularly pertaining to the requirements of various airworthiness (C.of A.) categories.

How many aeroplanes have I "put" on the Australian register, I guess over the years I have been involved in a dozen or more. A fact that is totally irrelevant to this discussion.

As to the LAME being "the last line of defense", you speak in jest, surely.

I have lost count of the number of aircraft, over the years, I have knocked back, as a result of defects found after the aeroplane has been presented to me for service, with an MR signed by a LAME.
When I sign a CAR 233 certificate, or otherwise accept an aeroplane for service, I am signing for far more that just the LAME's opinion of serviceability of the aircraft.

yr right, if you doubt this, just read CAR 233.

The LAME as the "last line of defense" --- I think not.

With reference to CAR 138, and a POH/FCOM/whatever name used, and the reference to the C-207, I would suggest that the application of CAR 138 is limited by the definitions of the contents of a POH, as detailed in the TCDS, and FAA advisory material on the subject, plus GAMA guidelines, for GAMA members.

If the restriction on LOP is in the airworthiness limitations, you have two choices:
(1) Comply, or;
(2) Negotiate a variation with the Type Certificate Holder, if this is successful, this will carry FAA (if it is a US built aircraft) approval of the variation.

In my view, given the legal mechanism for issuing a Certificate of Airworthiness in Australia (since 1998), CAR 138 cannot impose a greater limitation than presented in the original POH, just by the fact that something is printed in the POH. However, if CASA so chooses, it has other regulatory provisions to impose changes to a POH, usually in my experience, to the detriment of safe operation of the aircraft. And further, in my opinion, many such CASA directions are beyond power, in that CASA have no power to amend the certification status on an aircraft not originally certified in Australia.

Finally, I must say that, despite the length of this thread, I still have not decided whether yr right's "contributions" are for real, or just a bleeding long windup.

Tootle pip!!

PS: In the UK, in the 1960s, we were operating IO-540 for over 3000h TBO, low rpm, high boost and LOP. Never had a cylinder failure, only scheduled maintenance, with close trend monitoring, all to an approved program.

Aussie Bob

14th Apr 2014, 19:51

Finally, I must say that, despite the length of this thread, I still have not decided whether yr right's "contributions" are for real, or just a bleeding long windup.

I have been suspecting the same for some time. No one is that beligerant surely?

No Hoper

14th Apr 2014, 21:31

Reference cylinder longevity on aero piston engines:
Fit new cylinders on overhaul instead of the second or third life life ones go a long way to stopping problems.
Finally Cockney Steve admits he knows very little about aviation maintenance.
Reference Yr Rights contribution, consider the diverse and thought provoking information provided by the stalwarts of our industry and whether that would have been forthcoming without him

Ultralights

14th Apr 2014, 22:02

Even if Yr right is trolling, or widing up, it still has bought out the big names in aviation which has lead to some very interesting and enlightening conversation, and generally been an educational thread when you pick out the wheat from the chaff.

Aussie Bob

14th Apr 2014, 22:35

Reference cylinder longevity on aero piston engines:
Fit new cylinders on overhaul instead of the second or third life life ones go a long way to stopping problems.

But: Should you get these brand new cylinders and disassemble the valves to check correct seating before use? Will the supplied piston have the ring gap correctly set?

If you throw them on directly from the factory without checks will they be as reliable as carefully reconditioned items?

Serious questions!

Referencing yr right contribution: It has been one of the best parts of this thread, regardless of what it is, i agree.

yr right

14th Apr 2014, 22:36

Im certainly not trolling I dealing with real facts as I see them. To the point that the RAM statement has said what ive been saying. There a lot of backing down on certain points from the other side changing there figure's etc.
Classic is the whallya accident, if the engine was placed in high it would not have failed, its that simple

The myth that if you run LOP your engine with be better etc make o/h etc is just that, An engine run ROP will do the same. Its the driver that determines engine life and how he/she treats the engine over its life.

They bring up oh big radials where doing it, Yep they where. But you cant compare a large radial to a light weight lyc or tcm they just arnt built the same . Just look at the head radial free as in the breeze and the other two compact on top of each other. Then look at the valve stem large big and sodium filled to dissipate the heat into the guild the other two well what do you think, next the seat Radial most had rotating seats once again for heat removal and so the seat was not always in the same spot. The other two well. So if your going to compare apples compare them to apples and not to something else.

Im not in these other peoples league as to design etc but neither am I saying I am. What ive said and been consistent with is what I see on the hangar floor.

Now Jaba ask your wife would she approve any operation that flew outside the POH. I can answer that for you if you like.

Now as for CASA and the ASTB they are a joke you don't have to tell me that. But to run a course with no accreditation or endorsement's and say well this is it we done the data just believe us and all is well.
Like ive said fuel is cheap planes arnt falling out if the skies, if you feel the need to change and the POH says you can do it, but also don't go and cry to your maintenance org and expect pitty tell them what you done and im sure they will show you the results.

Cheers

yr right

14th Apr 2014, 23:01

Gerry 111 yer well V tail bonnzas have a horrible rep and gee if the where so good I guess beech would still be making them but they don't rrrr well you not a Dr are you by any chance.
Cheers

Aussie Bob

14th Apr 2014, 23:06

Thanks yr right, and I am reading all you have to say, perhaps your opinion on my questions above?

Thanks AB

43Inches

14th Apr 2014, 23:07

With regard the Whyalla accident;

The ATSB surmised that the left engine failed due bearing failure, which in turn the crankshaft failed. The ATSB tried to pin this on LOP operation when in fact their own report states the majority of Whyalla pilots were leaning to 50F ROP, with occasional leaning LOP as part of an experiment. Even if the accident day the pilot leaned 50F LOP the bearing had failed 50 operational hours previously and was doomed to fail that flight. The engine oil temperature had been trending high and even exceeded 245 prior to the accident day, this was hinting at something going wrong. It apparently was fixed a day or two before the accident.

The exact reason for the right engine failure is still unknown but the best guess was that the pilot pushed the power up with the RPM and mixture still set for cruise, this in turn resulted in severe detonation and cylinder melting. We do not know what method of leaning he used, it is still and forever will be speculation.

The other Chieftains in the fleet were checked and no faults found other than trend data maintenance associated with high temperature operation. Was this due to a few hours operating LOP or the majority hour operating 50F ROP. I know of two other Chieftains (of the 15 or so) that suffered crankshaft failure, neither of these were operated LOP and failed in almost identical fashion to the MZK.

The ATSB acknowledged that leaning in the climb may result in mild detonation, this would not have led to bearing/crankshaft failure or piston melting considering the climb power setting they were using. However Whyalla had an initial climb procedure to lean with power settings 38-40" higher than the recommended POH procedure.

yr right

14th Apr 2014, 23:07

and if anyone can tell me why im trolling or a wind up please let me know and also give us your qualification's and what makes you such an expert on the operation and maintenance of an aircraft engine.

Also ill just add here about px diff. Have a look at a top fuel engine letting go at full noise at over 300 mph and how the flame moves forward and into the driver, once again extreme but dose point out the power of low and high px diff.

Cheers and off to do some more science.

Oracle1

14th Apr 2014, 23:24

Then look at the valve stem large big and sodium filled to dissipate the heat into the guild the other two well what do you think, next the seat Radial most had rotating seats once again for heat removal and so the seat was not always in the same spot. The other two well.

Lycoming has sodium filled valves, just did a pot on an IO-550 Continental and the exhaust valve is allowed to rotate for even wear and hot spots. Both Lycoming and continental have relatively large guides to transfer heat out of the valve. Also the seat doesn't rotate the valve rotates, if the seat rotated it would pop out and snap the valve.

Please address the questions everyone are asking you yr wrong.

yr right

14th Apr 2014, 23:28

Yes most shops pull down and check valves and seats. Ring gaps are always checked before assembly. The only time I don't do it is if the cly come from an o/h shop and I'm in the field I have them the assy done for me in the work shop
Cheers

Walter Atkinson

15th Apr 2014, 00:07

Yr Right's explanation of how air moves under a cowl is on par with the explanation I got from my 13 yr. old daughter when I asked her the same question last night.

It is over-simplified, incomplete and, uh, wrong. It is, however, also on par (and incomplete) with what I was taught in A&P (LAME) school many years ago. It's that darned, ole, pesky data again.

We put a 36-probe CHT monitor in a Bonanza. We put dozens of tufts of yarn under the cowl and around the cowl openings. We then put a video camera under the cowl so we could WATCH what happened in real time as we flew. So far, we know of no other researchers, including OEMs who have done this.

Here's what happened (for free, data and knowledge you cannot get ANYWHERE else--at any price):

(BTW, what happens is NOT what we were taught happens, which is to some degree is "logical." Logic be damned when DATA is involved.)

1) the air comes in the far, outer edges of the cowl opening.
2) It travels along the outer edges of the cowl (in some case, outboard of the rocker covers)
3) the moving air mass on both sides of the cowl hits the rear backplate…
4) whereupon it makes a 90˚ turn toward the middle and meets over the spine of the engine.
5) This combination air mass then moves FORWARD across the spine of the engine and out behind the spinner and moves over the windscreen.
6) the tufts of yarn around the cowl opening are standing straight OUT----TOWARD the propeller!

THAT's why you get oil on the windscreen when you have an upper deck oil leak.

A relatively small amount of the turbulent air finds it's way down through the fins and out the lower cowl openings. Increasing the upper/lower deltaP helps a LITTLE.

What helps a LOT, is to alter the incoming airflow so that it does not go out of the front of the cowl. What helps even more is to alter the metal baffling to encourage more air where it's needed and less where it's not needed. Most cylinders are not evenly cooled around their circumference. We spent over a decade figuring out how to make the cylinders ROUND thru even cooling. That's why we have six CHT sensors on each cylinder.

I have been told that we know more about air-cooling, baffling, and air flow under a cowl than anyone on the planet. Based on my conversations with OEMs, that may be true.

I know this will rub poor, ole Yr Right the wrong way since he's probably convinced that the OEMs know more than I do, but I have the DATA--they don't.

After explaining this to my 13 yr. old and showing her the video, she said, "That's really cool. I bet not many people know that, huh?"

Walter Atkinson

15th Apr 2014, 00:14

So, we are to believe that radials are somehow different than flat engines?

They are both spark-fired, gasoline, piston engines with aluminum heads, steel barrels, pistons with rings, cranks that run on bearings made of the same material and have many more similarities than differences. They both reach peak EGT at the same F:A ratio. They both use the same aluminum alloy.

AND, when Little Johnny Deakin flies his Bearcat straight up, it's a horizontally opposed engine!

Now, tell me again, just what are the differences?

Oh, there is one main difference… the detonation margin on the radials is narrower. Detonation can be initiated in a big radial by the pilot's mis-use of the RPM lever. It's essentially impossible to cause detonation in a NA, conforming TCM or Lycoming being operated on conforming fuel. How do I know that? We've been testing this in the most advanced engine test facility in the world…. for over 15 years.

Walter Atkinson

15th Apr 2014, 00:21

While the notion that a valve rotates is a commonly accepted notion, it is not supported by the engine monitor data of a leaking exhaust valve. Neither is it supported by borescope observation. Honestly, whether or not it rotates cannot be proven or disproven. It can be proven that the notion that it rotates at a given frequency is definitely misguided.

Walter Atkinson

15th Apr 2014, 00:23

At this point, the reader is either fascinated by the discussion and possible new knowledge and understanding……. or, mighty upset.

:ugh:
:=
:D
:rolleyes:
:ok:

Ultralights

15th Apr 2014, 00:30

Walter Atkinson

15th Apr 2014, 00:30

Oh, BTW, some years ago I invited the owner of RAM to come to the APS course as my guest. He declined, actually saying that he already knew everything he needed to know.

I talked with their chief engineer a few months later and he said, "I KNOW you are right and that the science supports everything you say about engine management and LOP ops. But, my boss is hard-headed and he writes the checks. It's embarrassing."

It's important to recognize that ALL sources of data from Haywood, to Taylor, to TCM, Lycoming, NASA, Pratt & Whitney, and Wright, including the auto researchers (not to mention the most advanced engine test facility in the world in Ada, OK) are in agreement on the science.

"The physics are everywhere the same."
Sir Isaac Newton

I guess the guy at RAM operates under a different set of the laws of physics.

Six or seven years ago, I had a similar conversation with the VP of engineering at Lycoming. I showed him Lycoming's very own data that suggested that LOP ops were favorable to ROP ops at the same power setting. He said, "I will give you data to the contrary and I'll send it to you." Still waiting. Repeated requests went un answered--even in person, until he was replaced and no longer worked for Lycoming. Two years ago at the Cardinal Flyers annual meeting, Lycoming's president stated that there is no contrarian data for the fact that LOP ops are fine. He promised to change their website information and retract the "Experts are Everywhere" document. I guess the wheels of corporate inertia grind slowly; no changes as of April, 2014.

Aerozepplin

15th Apr 2014, 00:48

Like ive said fuel is cheap planes arnt falling out if the skies

I disagree.

I have at times been fortunate enough to have access to large amounts of aviation occurrence data. I had a particular interest in spark plug fouling, fuel mismanagement and carburettor icing, as these are largely preventable by the pilot. These three factors were the cause of well over half of all engine failures in the data I looked through. Especially when you consider that they can be hard to diagnose after the event, harder at least than a cylinder, valve, or bearing failure. Aside from the fact that some mechanical failures can be prevented by a cleaner burn.

In my opinion fear of the red lever, a total lack of understanding of what happens in the cylinder, and the spread of OWTs about the relationship between detonation and mixture have caused numerous engine failures, some of which have claimed lives. I believe that the information provided by John (and its great to read new writing from you too!), Walter, and co saves lives. Plane (ha) and simple.

The data shows that opinions like those from RAM are simply not true, and the idea of LOP operations being "on the edge" make me laugh. I guess they are on the edge, but where we've always been told to operate is over the edge. People like Yr Right, while likely very competent and dedicated to their jobs, but who ignore the mountains of data, are in my opinion doing the industry a great disservice.

My flight school training made me afraid of the red lever, and taught me to operate aircraft in a way that was inefficient, unsafe, and ignorant. Its a shame some fight so hard against those that are trying to change this.

Walter Atkinson

15th Apr 2014, 00:49

***A sincere thank you Walter, i am in the process of modifying the engine cowl of my aircraft, and have heard during the APS course of the cooling misconceptions, now you have inspired my to get the gopro out, some wire and tuffs, to do some testing on my own aircraft before i start rehaping, or moving cooling air inlets to the rear to take advantage of the stagnet air(higher pressure) in front of the windscreen, considering the new prop and spinner combination now covers most of the original front inlet, leaving only approx 2 inch gap either side of the spinner. my theory is to close off the nose inlets completly, and move the intake to the upper rear of the cowl, and direct the cooling air forward with internal ducting to above the cylinder heads, and continue down to the lower deck and out the convnetional manner. as for cooling on the ground, the engine is partially fluid cooled and oil cooled.***

WAIT, you may be pretty well off as it is. Ever look at the inlet on a Hurricane?

I'd collect some data before changing anything and collect data AFTER the changes. Otherwise, you have no way to know.

No Hoper

15th Apr 2014, 02:41

Maybe so Walter, but a flat 6 won't give you a hard on like a DHC-2 Radial at full noise

004wercras

15th Apr 2014, 02:50

Maybe so Walter, but a flat 6 won't give you a hard on like a DHC-2 Radial at full noise
I guess you keep one in the bedroom, Owen?

Ultralights

15th Apr 2014, 02:57

WAIT, you may be pretty well off as it is. Ever look at the inlet on a Hurricane?

I'd collect some data before changing anything and collect data AFTER the changes. Otherwise, you have no way to know.

this was my plan, fly as it, collect data, and see if changes need to be made, and/or make temporary blocking plates, and test again.

RadioSaigon

15th Apr 2014, 03:03

A masterpiece of unintended irony, that...

What on Earth makes you believe mine was "unintentional"? ;-) The OP however, which I suspect you may be referring to...

:ugh:

Walter Atkinson

15th Apr 2014, 03:24

***Maybe so Walter, but a flat 6 won't give you a hard on like a DHC-2 Radial at full noise
***

You've got that right!

Nothing, and I mean NOTHING beats the fire and smoke belching of a big radial on start-up! I am particularly fond of the R-2800s I flew behind on the C-46 Commando. Whoooooeeeee! (Kinda enjoyed my little R-985s on my Twin Beech, too. :D)

Progressive

15th Apr 2014, 03:43

Yr right,
Despite me sending you information to the contrary (from the manufacturer) you are still insisting that TCM fuel injection pump is "just a pump" when it is clearly a Pump and pressure regulator unit in one. If you need a simpler diagram/explanation see the FAA power plant handbook.

Have you every carried out a TCM fuel injector adjustment as per the SID? If so you would know that the pump output pressure (un-metered pressure)is set by adjusting the relief valve.

at the end of the day without data all you have is a pile of busted cylinders - no real evidence of WHY you have busted cylinders.

As for if the APS course is approved under part 66 by CASA - Part 66 only provides details of how to obtain a license. Individual courses are approved under 147 and 147 only approves courses leading to a license outcome. There are many courses required under part 145 or recommended by CASA which are not delivered by an approved organization.

These courses may be approved under an individual orgs exposition for commercial ops.
I cannot see CASA having much problem with an acceptable means of compliance to operate the aircraft LOP where crew have received data backed training.

Radial engines are no less susceptible to cylinder damage. They crack heads quite regularly, have very uneven fuel flows (due to induction arrangement) and are nearly all supercharged (limited boost control) Sodium filled valves do not guarantee better cooling or operation, they have been present for years in lycomings and actually contribute to valve problems.
See this link:
http://occonline.occ.cccd.edu/online/rfoster/The%20Rest%20of%20the%20Story-%20Valve%20Lifters%20and%20Tappets.PDF

If anyone has a copy of the original complete article please post is as I have lost mine.

What gives me the right to question your knowledge of engines?
I am a LAME
I spent 3 years overhauling engines including large radials
I spent one year overhauling fuel systems
And 15 years maintaining everything from tiger moths to bus jets including a fleet of chieftains
I am an aircraft owner
I am also assessment manager for a PART 147 MTO and I teach piston engine theory at all levels up to associate degree.

Old Akro

15th Apr 2014, 03:55

A sincere thank you Walter, i am in the process of modifying the engine cowl of my aircraft, and have heard during the APS course of the cooling misconceptions, now you have inspired my to get the gopro out, some wire and tuffs, to do some testing on my own aircraft before i start rehaping, or moving cooling air inlets to the rear to take advantage of the stagnet air(higher pressure) in front of the windscreen, considering the new prop and spinner combination now covers most of the original front inlet, leaving only approx 2 inch gap either side of the spinner. my theory is to close off the nose inlets completly, and move the intake to the upper rear of the cowl, and direct the cooling air forward with internal ducting to above the cylinder heads, and continue down to the lower deck and out the convnetional manner. as for cooling on the ground, the engine is partially fluid cooled and oil cooled.

Good on you.

There are some really good technical papers on this that have been presented to the AIAA (from memory). The keywords are pressure recovery, engine cowl, general aviation.

Here's one to get you going, but I think you'll find better ones.

http://www.n91cz.com/Interesting_Technical_Reports/CowlInletExit-AIAA_80-1242.pdf

The key issue is to turn the kinetic energy of the high speed air inlet into static pressure in the upper deck of the engine and to have a pressure drop access the engine to get the cooling air to go where you want it. From memory, the pressure drop from the top of the engine to the bottom is typically 4psi. Walter might recall the real number. But its relatively small, so finess is required.

You might end up replacing your wool tufts with manometer plumbing.

No Hoper

15th Apr 2014, 04:04

004 alias oleo and several other hide behind names, this is mens business so go back and play with your other little friends

Jabawocky

15th Apr 2014, 04:17

yr right
Now Jaba ask your wife would she approve any operation that flew outside the POH. I can answer that for you if you like.

I can answer it for you. NO, but learn to RTFM FFS is probably what she would tell you. I bet she could pick apart a POH in this area better than most, and most likely you too. And she is not a pilot. In fact her first go of the fun test on the APS course was 84%. Still not a pass mark but 20-30% above the typical private pilot who has an EMS. About 40-50% above a certain segment of the class demographics too. :ooh: Those who have done it might know this. So just like 10 pages back , you too have learned from this thread about critical thinking of a Chieftain POH, rather than just bold assumptions.

But to run a course with no accreditation or endorsement's and say well this is it we done the data just believe us and all is well.
No accreditation. Did you not read Walter Atkinsons comments a couple of pages back? :ugh: It has FAA accreditation and is rather generous about it too, but we do not believe in running around spruiking this and I do not here because we are in Oz not the USA. Is that not good enough for you?

And another big correction. And get this firmly in your mind...we actually tell people in the opening segment...DO NOT BELIEVE US......BELIEVE THE DATA. WE HAVE OPINIONS DATA DOES NOT.

Like ive said fuel is cheap planes arnt falling out if the skies, if you feel the need to change and the POH says you can do it, but also don't go and cry to your maintenance org and expect pitty tell them what you done and im sure they will show you the results.

Sadly the opposite is true.....YOU have a vested interest in us doing it your way. Andrew Denyer often says in the class, it is better for my business if you don't do it this way.

UL

You have enough GoPro experience, you could live stream it to us in a class :ok: :}

Jabawocky

15th Apr 2014, 04:19

Progressive
Yr right,
Despite me sending you information to the contrary (from the manufacturer) you are still insisting that TCM fuel injection pump is "just a pump" when it is clearly a Pump and pressure regulator unit in one. If you need a simpler diagram/explanation see the FAA power plant handbook.

Have you every carried out a TCM fuel injector adjustment as per the SID? If so you would know that the pump output pressure (un-metered pressure)is set by adjusting the relief valve.

at the end of the day without data all you have is a pile of busted cylinders - no real evidence of WHY you have busted cylinders.

As for if the APS course is approved under part 66 by CASA - Part 66 only provides details of how to obtain a license. Individual courses are approved under 147 and 147 only approves courses leading to a license outcome. There are many courses required under part 145 or recommended by CASA which are not delivered by an approved organization.

These courses may be approved under an individual orgs exposition for commercial ops.
I cannot see CASA having much problem with an acceptable means of compliance to operate the aircraft LOP where crew have received data backed training.

Radial engines are no less susceptible to cylinder damage. They crack heads quite regularly, have very uneven fuel flows (due to induction arrangement) and are nearly all supercharged (limited boost control) Sodium filled valves do not guarantee better cooling or operation, they have been present for years in lycomings and actually contribute to valve problems.
See this link:
http://occonline.occ.cccd.edu/online...%20Tappets.PDF

If anyone has a copy of the original complete article please post is as I have lost mine.

What gives me the right to question your knowledge of engines?
I am a LAME
I spent 3 years overhauling engines including large radials
I spent one year overhauling fuel systems
And 15 years maintaining everything from tiger moths to bus jets including a fleet of chieftains
I am an aircraft owner
I am also assessment manager for a PART 147 MTO and I teach piston engine theory at all levels up to associate degree.

You are clearly too progressive := :}

004wercras

15th Apr 2014, 04:32

004 alias oleo and several other hide behind names, this is mens business so go back and play with your other little friends

Now now Owen Meaney, FONC, Blackhand, McGrath 50 and whatever other names we know you use, I just wanted to come and play with you for a while!

A Squared

15th Apr 2014, 04:53

What on Earth makes you believe mine was "unintentional"? ;-) The OP however, which I suspect you may be referring to...

:ugh:

I don't, I copied your comment to show agreement with it. I guess that didn't come through.

yr right

15th Apr 2014, 05:14

What gives me the right. Cause I was ask to. For a start. I will get back to the other stuff later. After running god knows ex tacitly how many years large radial in excessive of 20000 and not one engine failure all ran to o/h life and no blow off tops of out cly cause we checked them on a daily bases I think I may know a little about things. And by the way we never ran lop ever.

Now also if you notice a large fan engine you can get a cloud forming in the intake if you run it on a coolish day with moisture. And Walter you would also no that the FW190 had a cooling fan behind the propeller.

I'm so impressed by you all trying your hardest to discredit me. Oh yes it was late sorry and I did say part 66. My mistake.

Cheers

Creampuff

15th Apr 2014, 05:15

Progressive

On reflection the tone of some of my responses to your posts earlier in the thread was inappropriate. :O

My sincere apologies – I guess I’m too used to responding to some of the more crass and ignorant frequenters of this forum.

A Squared

15th Apr 2014, 05:21

I'm so impressed by you all trying your hardest to discredit me.

I don't think you need any help, you're doing a fine job all by yourself.

Aussie Bob

15th Apr 2014, 05:31

I'm so impressed by you all trying your hardest to discredit me

Count me out, i am not trying to discredit you and never have. I keep saying: I value what you contribute.

Jabawocky

15th Apr 2014, 05:52

I'm so impressed by you all trying your hardest to discredit me.

Quite the opposite. We have been trying to help educate you. You clearly have a long history on the spanners and no doubt run a good workshop, but when there is a distinct lack of understanding because of the many years of BS in the industry, it needs addressing.

If I was of an opinion I could run my magneto's or vac pumps for 2000 hours untouched, and because I had done this before successfully , would you sign out my plane or would yo try to educate me in the errors of my ways?

If I was obstinate and belligerent about it what would you do?

Many of us here just want to help. Your misunderstandings are not your fault. We all had them once too.

Does this sound like an earlier post I made or the PM I sent you?

On the contrary some of us have been the subject of your attempt to discredit us. And that includes several folk on here I know are in a very well informed position.

The olive branch is still extended, just weltering under the stress.

:)

yr right

15th Apr 2014, 05:56

Progressive let me know if you like me to tell you my experience in aviation.
Cheers

ForkTailedDrKiller

15th Apr 2014, 06:14

Do NOT feed the troll!
Do NOT feed the troll!
Do NOT feed the troll!
Do NOT feed the troll!
Do NOT feed the troll!
Do NOT feed the troll!
Do NOT feed the troll!
Do NOT feed the troll!
Do NOT feed the troll!
Do NOT feed the troll!
Do NOT feed the troll!
Do NOT feed the troll!
Do NOT feed the troll!
Do NOT feed the troll!
Do NOT feed the troll!
Do NOT feed the troll!

:ok:

LeadSled

15th Apr 2014, 06:45

its one thing to say that but the regs don't allow that. The poh is over ridden by the log book statement and the M/M. ------ And the biggest problem is the AWI at each section have there own ideas and enforced them that way. ----- If the poh doesn't say it you cant its very clear as someone posted earlier. '

ye right,
The statement "The poh is over ridden by the log book statement and the M/M." is just plain legally wrong. CASA do not have the legal power to unilaterally amend type certification data for an aircraft not originally certified in Australia. Read CAR 138 (already quoted on this thread), the POH will be nominated in the TCDS.

"If the poh doesn't say it you cant its very clear as someone posted earlier." ---- Yes, somebody said that, but there have been many posts to the contrary, from people who actually know what they are talking about.

You seem to believe in the ideas that: All is prohibited that is not specifically permitted", in aircraft certification, the reverse is true. As Creampuff has pointed out, ( and he really does know the aviation law) there is no mention of descent in his POH, does that really mean that he has to stay up there forever, or commit a criminal offense to descend???

Tootle pip!!

Agrajag

15th Apr 2014, 06:55

So anyway, here's the thing:

When I started as a dewy-eyed youngster, lo these many years ago, it was with a burning thirst for knowledge. I wanted to know everything I could, so as to become better at my chosen path of flying. In those early days, I lapped up whatever I was taught, because it came from those vastly more experienced than I, and who was I to question it?

Along the way, that curiosity unearthed a few contradictions in the vast global store of knowledge about how best to do the job. Occasionally I was faced with the task of sorting that which was immutable fact from mere unsupported opinion. How best to do this?

A good place to start, it seemed, would be to listen most closely to those who could back up their opinions, or claimed facts, with evidence and proof. So the rare individual who tried to browbeat or intimidate earned a lot less respect than those who were able to support their claims with fact or, even better, demonstration. And so, like many others, I learned to heed the advice that was really worthwhile, and take the rest with a grain of salt. Healthy skepticism, and a desire to keep learning, have kept me alive thus far.

Among the interesting topics I encountered along the way, thanks to these new-fangled Interwebs, was a series of articles by one John Deakin. What the hell; can't hurt to read a bit. His take on engine management seemed to border on the heretical, yet here he was, bravely espousing his views for all to read and dissect. Even more curious, he seemed to have a lot of experience and data to support his views. This was getting interesting...

One thing led to another, and I found myself in contact with a few others who seemed to have been converted to this radical new/old approach. They too had a lot of cogent data, with which to persuade me that there was indeed something to this.

Eventually the boyish curiosity found me sitting in an APS classroom with a bunch of others, eager to learn some new stuff or at least spot a few holes in their attempts to convince me. Ah, wouldn't it have been so satisfying to find that I'd been doing it right all this time!

And so, the deluge of data began. For every question raised from the floor, there was a convincing answer, usually backed by more evidence. And, curiously, none of these answers contradicted any of the others or attempted to intimidate us into belief; usually a good sign that the lecturers know their stuff. LOP operation was an important part of the teaching, but it was only introduced after careful explanation of how things actually worked inside the engine, and was just one of many topics covered.

I have to confess that I was pretty much sold on the concept before I arrived. So I took particular interest in watching those who started out as skeptics, to see how they reacted to all this information. Now, it may have been groupthink, or they may have fed us something dodgy during the breaks, but even the tough cases had accepted by the end of the course that they couldn't argue with hard data, and I didn't hear anyone who was able to debunk what had been taught. (Not that anyone sought to do so, by then. Everyone departed keen to put all this new learnin' into practice. )

With yet more youthful enthusiasm, I too set about applying what we'd been taught. And blow me down, if the results in our aircraft didn't match exactly what I'd been taught. This wasn't just about LOP operation. It had to do with reading and interpreting what the engine gauges were telling me in all phases of flight, and making informed decisions based on that. I was never taught this stuff in my former GA life. The few questions that have arisen since then have been cleared up by follow-up contact with the gentlemen who ran the course.

So (and this is where I came in) I'll believe pretty much anything that's supported by proof that I can understand. What I won't cop, is someone physically or verbally sticking a finger in my chest and insisting that I take something on faith, just because they hold a particular licence or qualification - particularly if it contradicts something I can see or prove. I've benefited from training by many highly qualified people, but curiously none of them needed to shout or demean me in order to convince me of their credibility. They had my undivided attention, because they knew their topic and could demonstrate it.

Wouldn't it be nice if things always worked the same way in here?

LeadSled

15th Apr 2014, 07:56

Agrajag,
A most interesting post.
I came into the aviation field from an mechanical engineering background. Right from the word go, a lot of what I was taught, flying wise, conflicted with my earlier experience, including as a student running experimental engines designed to measure octane ratings of fuels and related characteristics.

To cut a long story short, from the time I achieved my first instructor rating, through the usual steps to CP/CFI, and later instructing on somewhat larger aircraft, I told all my students about my "policy", which was:

If I state something as a fact, I will always give you a reference, so you can check and verify.
If it is just my opinion (or commonly held opinions, OWTs etc.) I will state just that, it is an opinion for you to consider, and accept or reject as you see fit.

As a matter of interest, my first knowledge of what is here discussed as LOP, came from those research engines, where burning characteristics of various petrol grades at various fuel/air rations was examined.

yr right,
When Avgas is described as 100/130, 115/145 etc, what does that mean??
You have not addressed any of the questions I have asked of you??
What happened to your claim of being the "last line of defense"??

Tootle pip!!

yr right

15th Apr 2014, 08:01

Hey forky um do you suffer from OCD by any chance. Just noticed but you have not contributed a single word.
Cheers

No Hoper

15th Apr 2014, 08:15

At the risk of embarrassing them, Dan and his team at Chrisair did first start and ground runs on the most gorgeous Beaver on flloats, after priming oil system etc it came off the starter at about the third rotation.
Nine cylinders of freshly overhauled radial bellowed into life.
Young men and one young lady, maintaining a pristine example of the DHC-2B
I have some photos, if anyone knows how to post them I will send them

yr right

15th Apr 2014, 08:20

Lead sled i think you should read the regs. Have a look a a log book and the m/r and actually see and read what it says. The lbs is what the aircraft has to be maintain to. But what would I know hey.
Cheers

Aussie Bob

15th Apr 2014, 10:07

No Hoper, having an amount of time behind the controls of a DHC2 I would love to see them. PM sent

yr right

15th Apr 2014, 10:12

I have spent years on beavers . We wonted to keep the last one we had but sold her off. Saw her last year but.
Cheers

Jabawocky

15th Apr 2014, 11:08

Nop hoper post em here..... :ok: http://www.pprune.org/pacific-general-aviation-questions/505944-home-photos-dunnunda-mk-ii-47.html

T28D

15th Apr 2014, 11:10

cockney steve

15th Apr 2014, 11:11

Oh a costumer of mine mmm do tell
redefines "understanding drag" :}

#409 @ no hoper Finally Cockney Steve admits he knows very little about aviation maintenance.

ERR? I don't need to make any admissions , My posts speak for my understanding, or lack thereof, of the subject -matter under discussion.

I await the highly qualified , professional scientists and engineers calling me out as a billy -bull****ter.....the fact they haven't , leads me to think I bicht have a bit of an understanding.
#387 @ ultralights
Quote:Quote:
Originally Posted by yr right
Nah I don't need to stand up on a soap box and talk jibberish sorry...

Quote:yeah, right..

Post of the year in the Thread of the year!

:D :} :ok:
And, of course,Radio Saigon, who said so much with so little
:ok::ok::ok::D:D:D
@ Walter Atkinson, Thank you sir, for your fascinating dissertation, counter-intuitive. but entirely logical.....as a kid, I wondered how a Propellor could be able to pull an aeroplane al;ong, when there was a huge engine or cowl directly behind it.....logic said that this physical bulk would be pushed BACKWARDS by the prop, whilst the finer-pitch, weaker tips were trying to drag it forwards.....amazingly, it works and they fly.

004wercras

15th Apr 2014, 11:14

T28D, hence his name 'No Hoper'. He should stick with repairing postie bikes :ok:

yr right

15th Apr 2014, 11:43

A P&W r985 has 9 cly that's 2 more than 7 and 1 less than 10. Or are you useing a metric system.
Cheers

No Hoper

15th Apr 2014, 11:56

Don't worry about the children wandering in and trying to stir up an argument about technical matters beyond their understanding. When I stop laughing about the metric comment I will endeavor to post the photos. Only on iPhone right now.

yr right

15th Apr 2014, 12:04

To tell the truth I'm a little worried about the leave of knowledge. It's apparently that even though I been doing this a long time never had a problem I been doing it all wrong. Although my mates still tell me give it away come join us at the mines. Misses like that be home atleast.
Cheers

rnuts

15th Apr 2014, 12:07

T28D
I think you may have confused your 7 cyl wright cyclones with the 9 cyl P&W.

yr right

15th Apr 2014, 12:09

Gosh maybe they fitted an 1830 to it that give 7 cly yeh that's what it is. Silly me
Cheers

Oracle1

15th Apr 2014, 12:34

http://i875.photobucket.com/albums/ab320/oracle1_2009/aviation-forum-troll.jpg[/URL][/IMG]

jdeakin

15th Apr 2014, 13:27

To tell the truth I'm a little worried about the leave of knowledge. It's apparently that even though I been doing this a long time never had a problem I been doing it all wrong. Nothing I've said should be taken as "you're doing it all wrong," because I did not mean it that way. You may be a very fine mechanic/LAME. It's possible I might even bring my airplane to you for work. The finest mechanic I've ever known was a fellow named Greg Doyon at the Tacoma Narrows airport (TIW) near Seattle WA, USA. At first, I flew about 50 miles to get my annuals and other work done for about 10 years. Later, when I moved to California, it was nearly 1,000 miles, but I still had my annuals done by him. I did the "Owner Assisted" thing, and learned a great deal from him. In 15 years he never made a mistake, and turned out flawless work.

He was adamantly opposed to LOP, and when I told him I was going to have my V-35B upgraded to the Tornado Alley Turbo-Normalizer he desperately tried to talk me out of it. He grumbled a lot about it after it was done, but then admitted it was well done. He said, "Well, at least you won't be running LOP with it!" I smiled, and said, "That engine and Turbo has 250 hours on it, ALL of which was about 90℉ (50℃) LOP!, about 90% power." He was dumbfounded, speechless.

Later, I took him along for a demo flight and leaving the throttle wide open, the RPM full, I pulled the mixture briskly back to about 17 GPH (64 LPH). CHTs were all nominal, and less than they'd been ROP. The airplane was going like stink, about 190 knots TAS at 2,000 feet.

He fell right into my trap, saying, "Your IAS is well into the yellow." So I pulled ONLY the RPM back to 1800, leaving the throttle WOT. He nearly lost it, eyes bugged out, protesting. CHT's were down even more, of course.

He wasn't convinced yet, but he sure was puzzled, because it flew in the face of everything he "knew."

But it was based on science.

Sadly, that was the last annual for N1BE at that shop. Greg had a growing family, and had to take a job teaching at a local college, for MUCH higher pay. The plight of mechanics everywhere.

Where I have a problem with you, sir, is your foolish THEORIES about the damages you're seeing, and the ill-founded advice you're putting out here, and presumably elsewhere. You investigate, find the problems, and repair them. That's all well and good, and I salute you for it. THAT is your job, and I could not do it. But when the SCIENCE is presented, you blow it off with your version of the OWT (Old Wives' Tale.) You really do yourself and others a major disservice.

I think you also ought to let a spell-checker help you out, but that is just my opinion! :)

Best...
John Deakin
Camarillo CA

A Squared

15th Apr 2014, 14:52

No Hoper Please look carefully at the photos A 985 Pratt has 7 cylinders I know I own 2 of them your statement is somewhat off the mark:

Nine cylinders of freshly overhauled radial bellowed into life.

Oh, really?

Here's a photo.

I'm looking carefully.

I see nine, how many do you see?

http://upload.wikimedia.org/wikipedia/commons/thumb/9/9b/Pratt_%26_Whitney_R-985_Wasp_Junior.jpg/585px-Pratt_%26_Whitney_R-985_Wasp_Junior.jpg

You say you own 2 of these?

LeadSled

15th Apr 2014, 15:43

But what would I know hey. yr right,
Based on your posts, obviously not much about regulations generally , and certainly only very limited knowledge of the certification regulations, CASRs 21-35.

What on earth makes you think something in the front of an aircraft maintenance log over-rides the provisions of CASR Parts 21 -35, CAR 138 and FAR Parts 21-35. Maybe you went to the same CASA lectures that I observed.

As I have said before, based entirely on your contributions to this thread, and in my opinion your abysmal ignorance of quite basic matters, I still haven't decided whether you're efforts are a windup, or are really the efforts of a really truly living breathing and allegedly sentient LAME.

I cannot see an answer to one of the many quite specific questions posed to you buy Jaba, myself and others, you just bluster, an entirely reasonable assumption is that you just don't know.

Tootle pip!!

jdeakin

15th Apr 2014, 17:17

I still haven't decided whether you're efforts are a windupI'm not familiar with the term "Windup" used in this context? Would you elucimidate? :)

John Deakin

Jabawocky

15th Apr 2014, 19:38

JD,

A windup must be another Aussie term for winding someone up, getting them all wound up over something. So to deliberately poke the bear. To post controversy just to get a reaction.

Have a good afternoon :ok:

DB

PS As an example, we could try winding up yr right with a question on what is the appropriate fuel flow and why on a TNIO520?
And then ask how is it that TCM's laws of physics are so different to Lycomings, when on a IO540 the BSFC at full rich and full power is so much higher than the equivalent TCM IO550? (hint for the punters...one of them has their numbers right, one...well not so much)
We could get into the TRUE MEANING of SID97-3E?

Given the remarkable work done by yourself and Bill Ross, and publicly released recently, you have the upper hand, so lets see how long it takes to get to the bottom of this gem. By the time I get to Wanaka today I expect this will have generated some great discussion!

A Squared

15th Apr 2014, 22:28

I'm not familiar with the term "Windup" used in this context? Would you elucimidate? :)

John Deakin

As I understand it, much like "stirring the pot" with of an element of pretense.

yr right

15th Apr 2014, 22:56

so which comes first then. a SB an MSB a AD by country of Origin or an Australian AD,
Now if what you are saying is correct then every aircraft must follow the som provided by the Manufacture and shed 5 would not be able to be used.

I repeat
THE LOG BOOK STATEMENT is what all maintenance on a VH aircraft MUST COMPLY WITH. It is written on the M/R what the maintenance is done to for the event of a break down etc. Now do you know the difference between class A and class B in regard's to maintenance.

Do you understand a system of Maintenance. Have you every written one, I have and had it approved,
Cheers

Creampuff

15th Apr 2014, 23:54

Have a look a a log book and the m/r and actually see and read what it says. The lbs is what the aircraft has to be maintain to. But what would I know hey. …

I repeat

THE LOG BOOK STATEMENT is what all maintenance on a VH aircraft MUST COMPLY WITH. It is written on the M/R what the maintenance is done to for the event of a break down etc.You have the cart before the horse. You seem to do that a lot - confusing cause and effect.

The regulations are the horse and the other documents are the cart.

A Class B aircraft must have maintenance carried out when required by the aircraft’s schedule of maintenance (CAR 41). (A Class B aircraft is one that is neither certified in the Transport category nor used in RPT.)

If the holder of the COR for the aircraft has elected to use the CASA schedule of maintenance as the aircraft’s schedule of maintenance, the CASA schedule of maintenance is the aircraft’s schedule of maintenance (CAR 42B). If the holder of the COR for the aircraft has elected to use the manufacturer’s maintenance schedule as the aircraft’s schedule of maintenance, the manufacturer’s schedule of maintenance is the aircraft’s schedule of maintenance. (CAR 42A). If there is an approved system of maintenance for the aircraft, the approved system of maintenance is the aircraft’s schedule of maintenance (CAR 42C).

The election is made by filling out the approved form and giving it to CASA (CAR 42E).

There can only be one maintenance schedule at a time for an aircraft (CAR 42D).

If there is a change of holder of the COR for an aircraft, the new holder ‘inherits’ the old holder’s election (CAR 42F).

Note that nothing the log book says makes any difference to how the above rules operate.

The aircraft’s log book should reflect the COR holder’s current election. But if it says something different, the statement does not make the different thing so. In other words, if there is a valid election by a COR holder to use e.g. Schedule 5 of the CARs (i.e. the CASA schedule of maintenance) as the maintenance schedule for the aircraft, but the ‘log book statement’ says the aircraft is maintained in accordance with the manufacturer’s maintenance schedule, the maintenance schedule for the aircraft is not what the log book says. so which comes first then. a SB an MSB a AD by country of Origin or an Australian AD,

See the definition of ‘approved maintenance data’ in CAR 2A. :ok:

Every question you ask gets answered.

Every question asked of you gets obfuscated.

At what EGT will an exhaust valve be hotter: 50 deg F ROP or 50 deg F LOP?

VH-XXX

16th Apr 2014, 00:15

Here's a photo.

I'm looking carefully.

A Squared, is that one of those photos like in a shopping centre you look at it and see 9 cylinders but it is actually 7? Perhaps you are not looking at it long enough. Try half closing your dominant eye.

T28D

16th Apr 2014, 00:23

Yup I screwed up Sorry No Hoper and all a senior moment

Ultralights

16th Apr 2014, 00:26

At what EGT will an exhaust valve be hotter: 50 deg F ROP or 50 deg F LOP?

good question :E

A Squared

16th Apr 2014, 00:32

At what EGT will an exhaust valve be hotter: 50 deg F ROP or 50 deg F LOP?

good question :E

Why, yes, that *is* a good question. I wonder if yr right can answer it.

yr right? We're waiting for your answer.

Walter Atkinson

16th Apr 2014, 01:02

If he ever answers that question, try this one:

Is exhaust valve temperature related to EGT? Why or why not?

A Squared

16th Apr 2014, 01:04

If he ever answers that question, try this one:

Is exhaust valve temperature related to EGT? Why or why not?

I'd bet real money he'll never answer the first one.

Walter Atkinson

16th Apr 2014, 01:10

I'm not taking that bet! :ugh:

Andy_RR

16th Apr 2014, 02:34

This thread reinforces my belief that we should get a FADEC to do the engine management job, let the pilots fly and the LAMEs download the data every 50hrs.

Ultralights

16th Apr 2014, 02:40

This thread reinforces my belief that we should get a FADEC to do the engine management job, let the pilots fly and the LAMEs download the data every 50hrs

not much point if the LAME's dont know how to read or interpret the data they have downloaded.

No Hoper

16th Apr 2014, 02:50

Talked to the old bloke here, there was a 7cyl Jacobs radial in the Airtractor. The plate on this R985 indicates is built under license by Jacobs.

I'll take a punt on the exhaust valve question:
A richer mixture

Aussie Bob

16th Apr 2014, 02:56

One of P&W's finest from No Hoper! Another shot in Photos Downunder!

http://s25.postimg.org/mtrukgfn3/R985_9_CYL_copy.jpg

Aviater

16th Apr 2014, 03:39

not much point if the LAME's dont know how to read or interpret the data they have downloaded.

I love how this person lumps all Licensed Engineers in the same boat. This forum does not reflect the knowledge and understanding of ALL Engineers.

Whilst some opinions posted may be closed minded and different to others, it is extremely naive and narrow minded to come to an understanding that all LAME's must therefore share the same views.

There are some of us out there that are both Pilot and LAME and are happy to admit that there is always more to the story, no matter how much you know.

Any engineers that have done certified Diesel training will be very much in tune (pun intended) with reading data streams and interpreting the information from them.

As a side note, I don't know a single piston LAME who could afford to buy a seat on an APS course. Given an opportunity, I would be stoked to sit in on a course irrespective of it's location.

Brian Abraham

16th Apr 2014, 04:44

While the following applies to an engine long out of service, I think some principles may be of interest. Remember when reading, that these engines were always operated LOP, and had a 1,500 hour overhaul life if operated and maintained correctly.

I. The Cause and Correction of Exhaust Valve Seat Failures

A. This discussion will include basic principles of operation of valve and seat, types of failures, procedures at overhaul, changes in engine operation techniques necessary to obtain consistent cylinder reliability. This discussion will not include in detail abnormal causes of failure such as overspeeding or overboosting the engine beyond design limits and cracked or otherwise faulty parts. Temperature will be the key word throughout the discussion. The complete story of operation is presented in order that all personnel concerned can better understand all the overlapping phases of design, operation, type of failures, manufacturing, overhaul and operational technique necessary to insure reasonable cylinder life on any Reciprocating Aircraft engine.

B. The exhaust flame directly affects the valve, seat and cylinder; hence it is necessary to understand the effect of engine power, speed, and fuel air mixture on exhaust flame temperature before we can understand the complete operation of the valve seat. Starting at idle speed, the exhaust temperature rises rapidly with increased speeds until maximum cruise power is reached at which time the power enrichment valve starts to open which sharply reduces the actual flame temperature. Cylinder head temperature continues to increase at engine speeds above maximum cruise due to the increasing number of power impulses. Above maximum cruise the cylinder head has reached its basic maximum capacity to cool; and therefore, the amount of fuel is substantially increased as a combustion coolant to compensate for the cylinder cooling deficiency. Since use of added fuel over and beyond that normally used would reduce power excessively and since cylinders will operate satisfactorily under power at temperatures above those obtained at maximum cruise, a compromise between cylinder head temperature and power is used to give the best overall results.

C. The exhaust valve head is exposed to combustion temperatures during the power stroke and the entire head of the valve and part of the valve stem is exposed to exhaust temperature during the entire exhaust stroke; hence the valve is exposed either partially or completely to high temperature (1,800-2,600°F) for approximately 440° of crankshaft travel. Therefore, the valve is exposed either partially or completely to extreme heat approximately 37 seconds out of each minute. The valve dissipates this heat through the valve guide and through the seat where the two faces contact.

D. The ni-chrome steel exhaust valve seat used in Pratt & Whitney R-4360 engines is installed in the seat recess with a 0.0058-0.0073" pinch fit. This is accomplished by cutting the recess to a specific size, gaging and obtaining premeasured seat of a known size which will provide the required fit. The cylinder is then heated to around 500°F and chilling the valve seat to less than 10°F by use of dry ice. When the seat and seat recess are stabilized at room temperature, the seat is then between 0.0058-0.0073" tight. Ni-chrome R-4360 exhaust valve seat has a measured expansion rate of 0.0000045 per inch unit length for each degree Fahrenheit change. Aluminum has an average expansion rate of 0.000001234 per inch unit length for each degree Fahrenheit change. For example a 2.800" diameter valve seat and a 2.793" seat recess were elevated to 600°F; the 0.007" pinch fit is reduced to 0.0046" loose.

VALVE SEAT 0.0000045 X 2.800 X (600°-70°) = 0.00667

SEAT RECESS 0.000001234 X 2.793 X (600°-70°) = 0.0182

SEAT RECESS 2.793 + 0.0182 = 2.8112

VALVE SEAT 2.800 + 0.0066 = 2.8066

_______

VALVE SEAT LOOSE = 0.0046

When the cylinder is cold (70°F) and the engine is started the seat temperature rises first and to a considerable higher temperature than the seat recess. Hence, after ½ minute of operation, the seat temperature is about 600°F and the seat recess temperature is around 200°F, the pinch fit will have changed from 0.007" to 0.0099" pinch fit. Now the compressibility of aluminum is such that a maximum pinch fit of 0.007" is about all that will be retained, as the seat recess would be compressed approximately 0.0029" and would reduce the pinch fit under these temperatures of (600°F and 200°F) back to 0.007 inch. This, in turn, would reduce the pinch fit with a cold cylinder from the original 0.007" down to about 0.0049" pinch.

E. With the fundamentals now covered, it should be readily evident that the exhaust valve seat is retained in a hot engine by combustion heat saturated up by the valve seat itself and the valve. Take this heat away suddenly and you have a loose valve seat. The first several times a cylinder is exposed to this condition, it will probably do little damage because of a retaining lip designed into the seat specifically for this purpose. This locking device does not keep the seat tight; its only function is to retain a loose seat. Mechanical operation of the valve mechanism with a loose seat will eventually pound the seat into the cylinder head, upsetting valve clearance which in turn aggravates the pounding by the valve. This can then only result in the seat coming completely loose from the cylinder or total cylinder failure.

F. At this point it might be said “JUST FOLLOW THE NORMAL OPERATING INSTRUCTIONS IN THE AIRCRAFT OPERATING MANUAL” and you will have reasonable cylinder reliability. But some time must be spent discussing the specific condition known to induce cylinder problems:

1. Fast engine starts – The colder the weather the more detrimental – Keep engine RPM down until engine is warm.

2. Operation of engine less cowling – This should be avoided, except for short period oil leak check – RPM less than 1,200, CHT 160°C MAX, 2 minutes maximum.

3. In flight shutdowns – Not recommended, except in actual emergency.

4. In flight power reduction – Should be gradual – Never pull power off to idle when CHT exceeds 200°C, except in emergency.

5. Deterioration of the ignition system in service can be a major problem to cylinder life. Cylinders misfiring causes rapid cooling of the exhaust valve seat. This can result in a loose seat condition and will eventually cause seat failure. Malfunctioning engines should only be operated under emergency conditions.

6. Propeller thrust reversing – Should only be used when necessary – Causes high cylinder head temperatures and is always followed by low power (idle operation).

7. Engine shutdown – Must be below 180°C CHT – if this is impossible – Rotate engine several seconds with starter if possible.

8. Cooling Hood baffles – Must be latched and in good condition – always replace or repair defective hoods

Ultralights

16th Apr 2014, 09:19

Aviater I love how this person lumps all Licensed Engineers in the same boat. This forum does not reflect the knowledge and understanding of ALL Engineers.

Whilst some opinions posted may be closed minded and different to others, it is extremely naive and narrow minded to come to an understanding that all LAME's must therefore share the same views.

There are some of us out there that are both Pilot and LAME and are happy to admit that there is always more to the story, no matter how much you know.

Nice jump to conclusions,

i have met many GA LAMEs who do fantastic work, and i would trust my aircraft to them, but as said before, still believe firmly in OWT's even when shown the data, they cant make out what the data is telling them, just as i did when confronted with Vibe balance data streams post maintenance on a helicopter, but with little training,a willingness to unlearn what i thought, and relearn with the new generation of technology, i now know. Same went for my flying and engine ops, i was seeing the data, and evidence, done the course, now im wiser for it. it dispelled a lot of misconceptions i thought to be true.

Im not lumping all LAMES in the same basket, just stating that some do know, and some dont, some open to new ideas and theories, and a minority who will never change no matter the evidence presented.

as for my background for your reference, Multiple aircraft owner, Pilot, instructor, and maintainer...