Experts Are Everywhere – The Rebuttal

[Jabawocky]

12 years ago, in a land far away, one of history's great aviation article writers wrote what should have been a defining line in the sand that may have prompted Lycoming and TCM to quite writing inaccurate, misleading, contradictory, defamatory and otherwise moronic manuals, bulletins etc that have plagued and confused the industry for the last 30 years.

Not to mention that many who worked there knew this, but did nothing to stop it, until after they left or retired, then openly admit it was a disgrace.

Well without further ado, I recommend to you the rebuttal to one of the worst bulletins ever published. It should be noted that 3 years ago the President of Lycoming attended the Cardinal Flyers Organisation annual gathering and was a guest speaker where he declared publicly that they knew they had made errors with the EAE publication and that they would be taking it down from their website.

Enjoy Experts Are Everywhere – The Rebuttal Advanced Pilot (http://www.advancedpilot.com/articles.php?action=article&articleid=1838)

PS if this thread is being read some time in the future and the publication by Lycoming is removed, let me know, I will send you a copy for your own critical thinking analysis.

[Wally Mk2]

God 'Jabba' you know way too much there buddy:)

Someone called 'Otto' (Nik) started the whole ugly mess a few years back & yr trying to make it harder:-)

Keep at it 'Jabba' we bow b4 you for 'internal' advice:E


Wmk2

[Jabawocky]

I did not do it Wally....Deakin Did it! I wish I knew half what he has forgotten.

[Jack Ranga]

Walsta, if one fiftieth of the GA aviation community did what Jabba does there'd be more of them alive. In the age of the law for the lowest common denominator I'd prefer 'making it harder' than plowing into farking trees after last light with no runwary lights. Or actually learning where your peak cylinder temperatures & pressures are. ;)

[Sunfish]

Seeing is believing.

[Aussie Bob]

Jabba, first let me say, I have read the article in its entirety as well as devoured all the other bits on associated threads on LOP operations, great article, full of hard facts. but let's look very hard at one of the claims by an engine manufacturer ...

One that is receiving public attention by way of aggressive advertising is a company manufacturing fuel injection nozzles and espousing an operating technique that is "better" than that recommended by the engine manufacturer.

Now it would depend on your interpretation of agressive advertising but writing a series of articles, the fullfillment of which require the fitting of a custom injector and comprehensive engine monitoring is at the very least a form of advertising. Damn good advertising actually and one that works better than a bushel of brightly coloured fliers.

To put it plain language, what John Deakin is telling us is before we can run lean of peak we should fit custom injectors and individual cylinder monitoring.

I would be more than happy to do this if I owned something injected, meanwhile back in carby land there is not a huge amount here. Let's see, I used to climb at 25:25 but following these articles I started climbing wide open throttle and anywhere between full fine and 2500 rpm. All result in higher CHT. The major benefit for me has been much more agressive leaning in the cruise and big savings but the temps remain the same. Perfect comps last inspection and beautiful looking plugs but essentially all I was doing is what the manufacturer recommends.

Now what I would like is a custom exhaust, flow matched cylinders and some careful blueprinting but with over 1000 HTR it will be a long time coming.

[Wally Mk2]

I know that 'JR' it's just that 'jabba' has 4 brains, much like his beloved Otto cycle donks have 4 cycles so compared to us plebs he knows way too much:E

I operated recip donks for a few years b4 I seen da light ( am an ex grease monkey on both cars/trucks & planes) & I didn't know as you say 1/50th(easier to type) of what 'jabba dabba do' knows & I am still here alive & kicking (having never had a donk failure) giving the Mods a headache at times :E

Education is good, it's subjective though in some ways & we'll never really know if knowing all that stuff to that level will save a single life but it's nice to think that is may do so:)


Wmk2

[Jabawocky]

Aussie Bob,

Good stuff, let me try my best to shed some light on the things you note.

1. Aggressive marketing? The cheap shots taken in the Lycoming bulletin are aimed squarly at George and Tim and their company GAMI. GAMI have not done a lot of marketing ever, in fact they are very poor at it. If I were retired here I would go work there for a year just for fun, and ramp up their marketing, but they seem to do nicely on mainly word of mouth, because what they say they deliver. Ask any GAMI or TAT customer.

John Deakins articles were more about the science than promoting GAMI, he has never had a cent in payment from GAMI, and in fact the injectors in N1BE he paid for full price. What John did was provide education, he knew this stuff (coz he is really old) from flying lots of big engines LOP back beofre I was born. Back then they used BMEP, they did not have EGT, but it did the same thing. So he helped in the development of GAMIjectors from that perspective, helped George understand what he was observing and testing. If you want more of the history have a read of this article, it is a bit comical but has a good overview of the history. First Church of Combustion | Flight Today | Air & Space Magazine (http://www.airspacemag.com/flight-today/church.html) This link seems to be broken, worked recently, if you want a PDF copy of this PM me your email address and I will send it to you.

2. What John is trying to tell us is that provided you have a conforming engine, one that has balanced fuel air ratio's, no induction leaks and a good ignition system you will be able to run LOP like all the airliners did for hundreds of millions of hours. An engine monitor is actually MORE important for a ROP pilot and even more so for one that is operating ROP with poor F/A ratios etc. Basically there is no reason not to have one in any aeroplane ...even a cub!

An EMS is simply the best tool there is for operating efficiently, for improving safety in several significant ways, most of which people do not realise, for improving maintenance scheduling, and for fault diagnosis. And all these things save the owner bucket loads of money year in and out....and occasionally save the aircraft or life. But just fitting one is not enough, as the pilot becomes just like a dog watching TV. And hence how APS was born. It was not all about how to operate LOP.

3. Back in Carby land? I just spent two hours on Skype with two Americans in Texas, brothers, 3 planes between them 2 x carby one IO, and we focussed a lot on how the C182 O-470 with a JPI can be run LOP really effectively. How the engine will produce same powers and thus speeds on less fuel with cooler CHT's and cleaner heads, pistons rings and valves, by adopting the techniques of the old radial guys, who did this long before the EGT gauge was invented. And by the way they took the R3350 engines from 750 hour TBO's to 3600 this way.

So back in your carby land, which is no different to anyone else's there are huge gains in efficiency and egine health if you are willing to learn some new (old) tricks and get away from the accepted thinking of the 80's.

4. Comparing your climb methods, you did not fully describe so I will assume some things. If you did the old 25/2500 and full rich, compared to target EGT WOT/max rpm I would expect the CHT to be lower, less HP, full rich, much slower and longer climb, lower CHT (but not any gain from it) and dirtier cylinders and that is not so good. Often the 25/25 brigade get higher CHT's. Compared to the WOT/2700 and lean to target EGT (as it was at SL takeoff), which will climb with a similar combustion event all the way to TOC (except the power is reducing with height), get to height quicker, further down range, on less fuel and have (providing you have good baffles) steady and ideal CHT's all the way.

If you are struggling with this concept, you need some education somewhere along the way.

If you have ever flown a correctly configured Bonanza say with a TCM enine fitted with an ACFP (Alt compensating Fuel Pump) you will notice this system works VERY well indeed. Some of the readers will know what I am referring to. The target EGT method John (APS) suggest (and OEMs sort f describe but dont do it well) is exactly what the ACFP does. You just need to be the altitude compensator and even a single point egt gauge is OK for this task.

5. The major benefit for me has been much more agressive leaning in the cruise and big savings but the temps remain the same. If the temps are CHT remaining the same it sounds to me like you are not running LOP at all. That defies the laws of physics, and the laws of physics apply equally to all men and machine (except the F22 raptor :}) . It sounds like you are closer to around 40-75dF ROP where the pressures and temps are at their highest. To gain a thorough understanding of all this will take far more than a post or two on a forum. I think you know where I would recomend you go. Perhaps a seminar in Sydney in November (who said that.....:ooh: ) but the dates are not confirmed yet.

6. Now what I would like is a custom exhaust, flow matched cylinders and some careful blueprinting but with over 1000 HTR it will be a long time coming. Yeah and the gains would not be that spectacular, although better matched F/A ratio's would help a heap. And there are lots of things even in carby land you can do to address this.

Hope that helps a little Bob. :ok:


WallyMKII......... there is no hope for you....:E Those kero burners are made just for you....both of them :E :ok:

[Trent 972]

Interesting Rebuttal, however is anyone prepared to explain, expand or discuss this quote from the 'The punch line' paragraphs. (my bolding of the statement i'm talking about).

In the sales literature provided for this "new" technique, it is stated that Lycoming recommended this operational procedure in an owner's manual that dates back to the late '60's. No mention is made why it is no longer recommended on our present engines.

There seems to be a logical explanation for that. That's because Lycoming (and TCM) won't bother to do the quality control and set the specs high enough to ensure that the engines will operate smoothly when LOP. It's that simple. The stock engines usually CANNOT be operated LOP because of uneven mixture distribution among the cylinders, except a few, like those on the Malibu, and even those often require adjustment (with GAMIjectors) to run properly lean of peak.
It seems quite clear to me that even JD in Experts Are Everywhere – The Rebuttal (http://www.advancedpilot.com/articles.php?action=article&articleid=1838) says that without GAMIjectors, running LOP CANNOT be done properly.
Q. If it can't be done properly, then on those stock engines of which he speaks, should it be done at all?

(Missed your piece above Jaba as we posted about the same time.)
I wish I knew half of everything I've forgotten. :{

[Jabawocky]

Is old age getting to you Trent? At 45 I am starting to worry about it too :uhoh:

I would like to see JD jump in here some time and add his 20c+GST (22c) worth, but I think I can answer the question you pose easily enough.

Quite simply, you do not need gamijectors if you do not need them. GAMI will not sell you anything you do not need. Trust me or try it for yourself. I could even send you a data file for an engine with say a 0.3GPH spread, email it to them and the answer will be....touch nothing! Enjoy your engine.

As a clasic example of this, when my current engine was brand new from Lycoming, it would not run LOP, in fact we could hardly get to peak before it ran so rough it was unbearable. Andrew Denyer had to do some rough injector flow adjustments based on my observations and his skilled guesswork, just to get the F/A ratio's to a point where we could do a GAMI lean test. Even then the result was 1.2GPH. I cant even imagine what it was before.

This is clearly what JD refers to in the article about manufacturers not meeting their own tolerances. The reason the engine often require GAMI's is there is no other way to balance the F/A ratios. Fixing the air side of things is pretty damned hard as the volumetric efficiency is all over the place, and not easily adjusted. No STC there! So you can fix the ratio up by fiddling the fuel delivery, simply and with an STC. How easy.

Anyway we got it to a reliable 0.3 - 0.4 spread and we flew it that way for about 700 hours before fitting GAMI's and straight out of the box we got 0.8 spread. Now you would think that would be worse, and by data it was, but the in flight performance was just as good as our old 0.3 set that were flow adjusted standard injectors. Why? Better nozzle design and spray from the GAMI. This is significant in N/A engines and less so T/C engines. Long story.

Anyway.....back a few years ago I was aksed to coach a fellow in Victoria with his brand new IO540 powered machine, and my first task was to get him over the fear of the red knob and at low level high power and running in. I kid you not, the same engine installation the only differece was the serial number (and the F/A's).....WOT/2500 and BMP to 80dF LOP and it ran smooth as a babies bum.

So, going back in history even further, the big piston airliners all ran LOP and even carby O-320's run LOP and Capt Bob Miller in 1928 ran his Jenny LOP (he actually watched Lindburgh tune the Spirit of St Louis at night...even older than Deakin!).....non of them had injectors let alone the chance of GAMI's. But in todays Lyc/TCM flat opposed engines the simple and STC approved way is work in a set of GAMI's and this may involve swapping a couple over with a second or maybe third attempt. But if you do not need it.....you do not need it.

So your question should it be done at all.....Absolutely YES, so long as it has balanced F/A ratio's, otherwise it will shake and rattle and your wife will go mad at you.

Now more importantly for the ROP pilot. Nothing wrong with that at all. But if you are, when you have poor F/A ratio's, and you decide to be optimal that you need to be 125dF ROP, that means the leanest is at 125ROP, the others are much richer, maybe out to 250 or so. What is your fuel flow? The answer is simply many GPH more than it needs to be. Get your F/A ratio's fixed, the cylinders indiviually will behave the same and your 125dF ROP power setting will be the same HP, same speeds, on way less fuel. How good is that!!!!:ok:

[Shagpile]

Jaba I'm a massive fan of LOP in aircraft with proper instrumentation but for my 540 with a single CHT & EGT, so far I've been operating fairly rich...not even what I consider near 50 ROP [well on the 'safe side' of rich] at the expense of fuel, especially on short flights.

Is that article suggesting it would be safer for me to pull it back to LOP? He gave the example where running 50 ROP and one injector is partially blocked, that cylinder would be getting smashed with zero indications, where as running 50LOP would immediately show as rough running.

I would have thought the other argument would also apply....if I were to pull the mixture back till I feel the power reduce, then add a little [pretty much LOP], if one injector is rich, that would be doing the same thing, unmasked. Unless that is near impossible for an injector to be that rich? (As opposed to the first case which was a blocked injector).

So pretty much the question is, for people with only a single old-school CHT/EGT dial, what is the consensus for a fairly smooth engine - very rich or LOP ?

[Aussie Bob]

Ok Jabba, you have convinced me, I am prepared to buy and fit an engine monitoring system. Any recommendations for an 0-360? Being me, I don't mind the very best ... but it will need to go in a standard 2 and a bit hole.

Sadly I will have to put up with a bit of ridicule from my LAME but I can cope with that. Otherwise, a recommendation of someone who might fit the entire plot would also be appreciated.

[Jabawocky]

Bob, of the certified instruments and depending on installation of the existing aircraft instruments, the Auracle is probably the pick. You can, and talk to Tony Brand at Horsham Aviation install a Dynon EMS D10, and this is awesome, especially if you fit the EFIS D10A as well. Full fuel computer etc for less money than an AuRacle alone.

Up to you. The JPI's are good too, but the AuRacle has a better layout, maths that work right for ROP and LOP % power settings. Its just a nice intuitive unit.

One thing I would say is this, the min spec is all EGT, all CHT, fuel flow. Then if you can have MP and RPM. All this logged at 2 seconds or better. This makes it a powerful diagnostic tool. Will pay for itself.

If you need to discuss this further PM me.:ok:

[Walter Atkinson]

Shagpile:

If you have balanced F:A ratios, it will run smoothly LOP. No worries. No need for an engine monitor to do that. If it runs rough you have UNbalanced F:A ratios, an ignition problem, or induction leaks--it's a non-conforming engine.

If you set the mixture ROP it will run perceptibly smooth even if you have poor F:A ratios. Without an engine monitor you have no way to know that when ROP.

So, yes, run LOP to confirm balance F:A ratios, a good ignition system, and no induction leaks. Once oyu know these things, you can set the mixture anywhere and know that things are OK.

As for the Carby guys... LOP is quite doable if one knows how to properly use carby heat to get optimal fuel vaporization.

As for Lycoming and John Deakin...
1) Lycoming was intellectually dishonest with that publication. (IOW, they lied)
2) Deakin has NO, Zip, NADA, affiliation with GAMI or TAT.
3) When he says that you need GAMIjectors to do this, he means to say that you need balance F:A ratios and so far, TCM nor Lycoming are able to deliver their engines AS DESIGNED--with balance F:A ratios. It has taken a small company in Oklahoma to accomplish that. BUT, some engines do not need GAMIjectors, so it's not a 100% issue.

[Trent 972]

Thankyou Walter and Jaba.
Therefore in essence, any IO engine that runs rough when leaned a little to a lot past the stoichiometric mixture, should not be run LOP in accordance with what JD meant to say.
Got it. :ok:

[Ultralights]

i wonder if ROP issues might be the core of the issues some have with all aluminium engines made in QLD?

[Jabawocky]

Trent....what it really means is get it fixed.

It may be an induction leak or spark plug or lead issue preventing proper operation, or simply the fuel delivery. In any case if it is a "conforming" engine the way any engine should be built or maintained it will be fine. Not being able to run past peak is a clear sign the engine is sub-optimal.

UL..... partly but there are a bunch of issues there besides F/A ratio's. Best we do not drag this thread down that road, although we can talk in private if need be.