Mixture rich for taxi?
Grandpa Aerotart
CR never would I suggest you go against your employer's wishes or SOPs.
If an aeroplane is not fitted with the technology there is **** all you can do but operate the aircraft within it's technological constraints.
The knowledge gives the ability to not do the things that will cause damage and a basic understanding of how the machinary works and the interaction between MP, RPM and Mixture...the WHY of it all.
You could gather all the information together and present it to the CP/owner in a logical manner and perhaps they may act on it. Ramming it down their throat and shouting that this is THE ONLY way an engine should be run...while true...is more likely to get them offside from the get go.
Point out, or print out, Deakins avweb columns...particularly Mixture Magic.
Would they be interested in seeing some really interesting graphs done by the engine manufacturers.
Show them my lean test and explain what it is.
Tell them it seems that this could really save them some serious money.
Then leave them alone to contemplate it.
Wait for them to display interest and continue, in the mean time, to operate their aircraft in the manner they wish you to....but with the (hopefully) increased mechanical SYMPATHY that I hope this thread has highlighted.
You always catch more fish with an enticing bait than with a lump of wood....having said that dynamite works good too
In the final analysis if it's your employer's aeroplane you must operate it as they wish you too.
I had a long chat with the, then, boss of airworthiness at CASA about 4 years ago. He was aware of this technology and had seen it work first hand at GAMI's test stand and agreed that this was the "only way these engines should be run"...those were his exact words. "Put together a POH ammendment and we'll look at it and approve it".
I have no idea whether he still works at CASA...he struck me as a really knowledgable, switched on and interested fella.
If an aeroplane is not fitted with the technology there is **** all you can do but operate the aircraft within it's technological constraints.
The knowledge gives the ability to not do the things that will cause damage and a basic understanding of how the machinary works and the interaction between MP, RPM and Mixture...the WHY of it all.
You could gather all the information together and present it to the CP/owner in a logical manner and perhaps they may act on it. Ramming it down their throat and shouting that this is THE ONLY way an engine should be run...while true...is more likely to get them offside from the get go.
Point out, or print out, Deakins avweb columns...particularly Mixture Magic.
Would they be interested in seeing some really interesting graphs done by the engine manufacturers.
Show them my lean test and explain what it is.
Tell them it seems that this could really save them some serious money.
Then leave them alone to contemplate it.
Wait for them to display interest and continue, in the mean time, to operate their aircraft in the manner they wish you to....but with the (hopefully) increased mechanical SYMPATHY that I hope this thread has highlighted.
You always catch more fish with an enticing bait than with a lump of wood....having said that dynamite works good too
In the final analysis if it's your employer's aeroplane you must operate it as they wish you too.
I had a long chat with the, then, boss of airworthiness at CASA about 4 years ago. He was aware of this technology and had seen it work first hand at GAMI's test stand and agreed that this was the "only way these engines should be run"...those were his exact words. "Put together a POH ammendment and we'll look at it and approve it".
I have no idea whether he still works at CASA...he struck me as a really knowledgable, switched on and interested fella.
Last edited by Chimbu chuckles; 5th Nov 2006 at 12:51.
Leaning without an EGT gauge could be done as you described, even on the bigger engines, but I wouldn't persist with for too long. Alright to get home. The EGT gauge is a mandatory instrument on the IO-520 and others, I presume.
Lean at idle to where the engine runs smooth ie. just rich of the rough spot.
Fuel flow at T/O in the IO-520 should be at least 100lph or better at sea level ISA.
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If anyone is interested I have a 150 page document which contains all the relevant John Deakin articles including graphs on the LOP subject. It also contains a chapter on Over Square operation. Again with John Deakins articles on the subject. There are also extracts from other great writers on the subject.
I put this all together about 18 months ago for a submission to management.
The first 18 pages are my own scribblings on the pro's and con's. Which may or may not be relevant to other operations.
Be aware that while LOP and over square is a great way to operate an engine, it may well not be the best way for a company to run an operation. Particularly with junior pilots or pilots who have no passion or interest in how or why an engine works.
This document comes in a sleeved and bound format and would not require to much effort to tailor to someone else's operation.
If you would like a copy PM me or if you need more info just ask through this thread.
Anyone looking to further their knowledge on the subject of LOP I can thoroughly recomend the following:
Sacramento Skyranch Engineering Manual, this is a must have for anyone interested in piston engines.
Kas Thomas Aircraft Powerplants, believe there might be a more up to date version.
John C Eckalbar, Flying High Performance Singles and Twins, a great read!
Curtiss Wright Engine Handling Manual, you can order this one through John Deakins Pelican's Perch sight. This is more of a insight to the history of LOP theory.
Also worth an internet search on the automotive develpments that occoured through Europe during the 70's on super lean technology. They were able to sustain fuel/air mixture ratio's that engineering science believed at the time were impossible.
Regards
M
I put this all together about 18 months ago for a submission to management.
The first 18 pages are my own scribblings on the pro's and con's. Which may or may not be relevant to other operations.
Be aware that while LOP and over square is a great way to operate an engine, it may well not be the best way for a company to run an operation. Particularly with junior pilots or pilots who have no passion or interest in how or why an engine works.
This document comes in a sleeved and bound format and would not require to much effort to tailor to someone else's operation.
If you would like a copy PM me or if you need more info just ask through this thread.
Anyone looking to further their knowledge on the subject of LOP I can thoroughly recomend the following:
Sacramento Skyranch Engineering Manual, this is a must have for anyone interested in piston engines.
Kas Thomas Aircraft Powerplants, believe there might be a more up to date version.
John C Eckalbar, Flying High Performance Singles and Twins, a great read!
Curtiss Wright Engine Handling Manual, you can order this one through John Deakins Pelican's Perch sight. This is more of a insight to the history of LOP theory.
Also worth an internet search on the automotive develpments that occoured through Europe during the 70's on super lean technology. They were able to sustain fuel/air mixture ratio's that engineering science believed at the time were impossible.
Regards
M
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Just had a try through Deak's article #42 Lycoming speaks on LOP and the link worked.
It is Lycoming document SSP700A
Try also:www.lycoming.textron.com/support/engineOperationTips/SSP700A.pdf
It is Lycoming document SSP700A
Try also:www.lycoming.textron.com/support/engineOperationTips/SSP700A.pdf
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First time in a C210 I leaned after start-up and had the grade 3 instructor admonish me for doing so. The engine sounded awful on a long taxi and we had plug fouling we had to clear during run ups. After landing I instinctively did as I was taught and leaned again. This time he didn't notice for a few minutes and once he did he said something along the lines of "Geez, you can hear the difference, it sounds so much better leaned. Lets just leave it there".
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An iteresting concept, I once flew with a guy who was taught to never lean below 5000'. Does wonders for your fuel flow in some types. I know of one type that goes from the low 30 l/hr with leaning to 50 plus if flown full rich.
I think you should be taught to lean in the air and on the ground from day one as this should breed good habits from the begining.
As for the clearing a fouled plug, if you have a CSU try cycling the CSU once or twice as the change in pressure can dislodge the carbon on the plug.
I think you should be taught to lean in the air and on the ground from day one as this should breed good habits from the begining.
As for the clearing a fouled plug, if you have a CSU try cycling the CSU once or twice as the change in pressure can dislodge the carbon on the plug.
Grandpa Aerotart
My pleasure...I will make the same offer I made to barondriver...who has been PMing me with lots of questions
...PM if you are having difficulty getting your head around some of it.
...PM if you are having difficulty getting your head around some of it.
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First time in a C210 I leaned after start-up and had the grade 3 instructor admonish me for doing so. The engine sounded awful on a long taxi and we had plug fouling we had to clear during run ups. After landing I instinctively did as I was taught and leaned again. This time he didn't notice for a few minutes and once he did he said something along the lines of "Geez, you can hear the difference, it sounds so much better leaned. Lets just leave it there".
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Damn you Chimbu!
Was a time a bloke could taxi the Forked-tailed Dr Killer around - mixture full rich and the IO520 burbling with much machismo (?)!
Now, since you have educated this ignorant aviator, the bloody thing just purrs like some sort of poncy cat!
R
Last edited by Ratshit; 19th Nov 2006 at 06:21.
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Just thought I'd add my 2c to the leaning thing...
The instructor I flew with first off never mentioned anything about leaning the mixture during taxi, but recently I've been flying with another instructor a bit and he ALWAYS leans it during taxi. Told me about the spark plugs and all that stuff, was interesting to find out. So yeah during taxi I do it these days. But I bloody sure as hell make sure my mixture's back to rich before the runup!
Anyway, my 2c...
The instructor I flew with first off never mentioned anything about leaning the mixture during taxi, but recently I've been flying with another instructor a bit and he ALWAYS leans it during taxi. Told me about the spark plugs and all that stuff, was interesting to find out. So yeah during taxi I do it these days. But I bloody sure as hell make sure my mixture's back to rich before the runup!
Anyway, my 2c...
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Bankstown Boy - "But I bloody sure as hell make sure my mixture's back to rich before the runup!"
If you're going to lean for ground ops, lean aggressively and you'll have no issues. What you DON'T want is a half-baked leaning effort and then forget to richen for high power - the engine will run fine on take off and climb up until it burns the guts out of a piston or detonates itself to a standstill!
