Very low power ops and excessive “babying” of our recip engines does them no good and done over long periods bugger them up just as bad as running them over the top.
IMHO, in the contexts that these well known people make those statements, these statements are vague. What is “babying”?
Are they saying that if you buy a plane with a 20000ft ceiling, you should throw away the top 12000ft of that capability because you cannot achieve 75% above 8000ft? That would be nonsense. It would amount to saying that every plane without a turbocharger is useless crap as soon as the wx is not CAVOK, and would certainly be useless crap for IFR.
What IMHO they are talking about it people flying at say 40% power at 3000ft, which is daft.
then surely it’s going to happen whether you operate with the throttle closed for 10 seconds or 10 minutes.
Exactly. There is no mechanism in the engine which is going to take 10 minutes to build up. If there is some resonance of a lightweight item like a piston ring, it would start within milliseconds of the favourable conditions being presented. So any engine would be rapidly shagged – because we all do this when landing.
Operate your engine anyway you want.
You asked for my opinion, and it’s based on 20+ years of first-hand GA maintenance and thousands of articles, discussions and text-books consumed over those years.
Operate your engine anyway you want.
Rather then getting upset, Michael, can you explain how one could reconcile the assertion about ring flutter at low MPs (etc) with the certified ceilings of so many non-turbo aircraft going to FL180+ ?
How could Lyco accept the approval of their engines in those airframes’ Type Certificates if the engines could be trashed just by flying within the TC?
There has to be more to this.
Peter wrote:
How could Lyco accept the approval of their engines in those airframes’ Type Certificates if the engines could be trashed just by flying within the TC?
ROTFL !
Give me a sec to stop laughing !
Michael wrote:
Type Certificates if the engines could be trashed just by flying within the TC?
Go fly your Lyco @ Full Rated Continous Power setting and report back to us !
Oh yeah, don’t forget to not go over the 500° CHT limit jsut for good measure …
Maybe I am not making my point as clearly as I should, Michael. But that’s fine. I am off to yoga 
Peter, I’m also with Michael. I think ring flutter is real and happens over a period.
My IA is also with Michael. I respectfully suggest Your elevated oil consumption has been caused by operation at too high an altitude over long period at consequent low power cool operation at high revs giving insufficient internal pressures causing ring flutter which over a long period will knacker an engine. Just because it did not happen earlier does not mean it will never happen.
Furthermore, just because your aircraft has a sevice ceiling of 20,000ft it does not mean you should operate a NA engine up there for long periods. In fact you are the only pilot I know who does operate up there with an NA engine. Lycoming won’t stop you, it’s good for their business.
Deakin and Braly have written extensively on this subject particularly on the Avweb Pelicans Perch series which are excellent. I recall one article which argued (Alioth should search for it) why most glider towing aircraft reliably reach TBO. It’s worth a read.
Another issue you have up at high level is the engine is cooler than it should be. One of the reasons a glider towing aircraft is ok is the thrashing it gets during the tow, it gets good and hot before the descent.
If oil is cooler than it should be which it is at high levels and low power, the high rpm can shear the oil so it does not lubricate so well. There is a contributor to this site who can explain this far better than me even though I studied tribology 40 years ago.So, putting all these things together I’m not surprised you engine has EVENTUALLY given trouble. Fortunately , you may have caught things in time but I cannot understand why you are fighting the evidence. Again, I’m with Michael when he says fly your engine flat out and hot, as hot as you can within limits. We are only trying to help.
My experience: you fly the engine in all possible ways, you read five million articles, pray for it every sunday and do all kinds of voodoo stuff – the engine is completely unimpressed and it will still break when it feels like breaking.
The longer i fly, the less i think of all that homeopathy :-)
The truth is usually more complex than simple statements.
The surprising thing is a lack of experimental or engine shop reported data supporting ring flutter.
