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

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

Jabawocky

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

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

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

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

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

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

Lead Balloon

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

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

Here is a selection of quotes from the GAMI website:

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

Is this a summary of the 7 pages?

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

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

Running LOP is more controversial but has advocates.

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

Quote:

---

Running LOP is more controversial but has advocates.

---

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

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

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

Tootle pip!!

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

from "Continetal Guide on Engine Care." http://www.insightavionics.com/pdf%2...ontinental.pdf

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

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

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

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

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

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

Gentlemen:

Please allow me some observations and explanations:

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

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

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

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

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

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

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

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

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


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

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

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

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

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

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

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

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

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

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

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

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

now back to the regular LOP debate.

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

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

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

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

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

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

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

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

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

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

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

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

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

:ok:

extralite:

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

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

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

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

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

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

Go figure?

What's a fella to do?

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

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

***

FWIW:

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

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

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

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

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

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

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

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

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

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

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

The data will be compelling for you to observe.

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

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

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

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

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

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

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

Thanks for the reply Walter.

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

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

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

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

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

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

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

How are leaded aero engines immune to this?

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


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

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

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

Hope that helps.

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

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

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

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

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

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

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

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

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

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

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

Also:

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

Walter:

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

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

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

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

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

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

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

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

Your closing sentence smells sarcastic and suggests feigned confusion.

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

Pb Ballon is correct
:ouch:

oggers, let me answer each one at a time.

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

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

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

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

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

I don't have a 10' 2700 RPM photo, because that would be illegal here (wish I did) but I have done LOP take-offs at around 91% power, and the take off run for my plane becomes like a Bonanza, almost exactly and the CHT's are unbelievable good. Most GA planes need the extra ponies so it is not suggested for everyone else. But it proves the point well. What I do have is an old photo from when "morno" was flying and this is 1000' and 2400 RPM, and the power was about 80%. Enjoy!
http://i849.photobucket.com/albums/a...0/photo2-3.jpg

Here is one in the cruise at 10,000' (new panel)
http://i849.photobucket.com/albums/a...ps3fcaaa71.jpg

And here is the concept graph, derived from real data, and all the answers to your questions can be found here. The two brown 1/BSFC curves represent a moderately high power, say 80-85% for the unbroken line and about 70-75% for the broken brown line. As the %age power reduces that brown line peaks a little further to the right. If it were 65% power or less it would peak in the -10 to -20 from peak region.
http://i849.photobucket.com/albums/a...psbfb07cbb.gif


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

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