low power settings for endurance flights

[banjo]

low power settings for endurance flights is an interesting topic

but l have a friend who said don't do it.

he's a fish spotter and a few years ago he carmalized his engine because he was using low power setting.

Does anyone know what would a safe time to run low settings for?

[conom06d]

Do as the POH states. I havent personally flown at a low power setting yet cuz Im a speed freak, but I know my M20B states at 16" and 2300rpm for an endurance flight I can fly 7.7 hours which is roughly 850 miles. It will reduce the gph to 6ish compared to 9 and 120mph compared to 145mph.

[carusoam]

Interesting question...

I briefly considered wave riding on a windy day in my M20C a few years back.  Low RPM, low manifold pressure and I was enjoying low powered flight.  This was at lowest settings in the POH. 

Settings outside the POH, probably don't maintain level flight, unless the oragraphic lift is really strong!

There is probably a cylinder head temperature and oil temperature to maintain.  (see green on the indicators)

Cold cylinders will fit tightly around the cylinder rings and generate additional wear.  Low power settings will really allow for cool cylinders.

I am not sure what carmalizing an engine is,  Banjo, can you add detail to this?

Best regards,

-a-

[Hank]

My POH has 20"/1950 RPM from sea level to 12,500 msl. I've played with it in the practice area just to get a feel for it. "Different" is the best I can say . . . Endurance is 7:45 at sea level, dropping toward 6:00 at 12,500. Feels kind of mushy. I don't recall the AI reading, but the book says speed should start in the 120's and rise towards 150 mph, with range starting at 1000 miles and dropping to just under 950.

Depending on the model/year in question, yours will be different.

[Piloto]

I can not see any damage to an already break-in engine. If I am over the North Atlantic heading east I would rather be in the low power setting than on the high power setting. At low power setting the stress on the engine parts is half of that at high power setting, thus the possibility of blowing a cylinder or breaking a connecting rod is very remote.

José

[flight2000]

If you haven't read Jonathan Paul's detailed account of his coast-to-coast, non-stop flight in his 65E, I highly recommend it.  He went from San Diego to Savannah in one shot and he details everything. 

Bottom line, he was running roughly 15" MP and 1950 RPM the entire trip while burning 5.3 gph. 

http://razzolink.com/~jonathan/DreamAchieved.pdf

Brian