Author Topic: Feathering props (Read 451 times)

-lynx- · « **on:** July 18, 2000, 11:10:00 AM »

OK guys, help me out here: I can't believe that the prop of a dead engine would rotate at gliding speed. It doesn't on my microlight (Rotax-503, 2 cyl, 500cc, 50hp), it didn't the only time I tried engine off in a Cessna 150 (Lycoming, 4 cyl, 2-3,000cc?, 110hp).

I can't see a prop just leisurely rotating at 120-140kts being attached directly to the crankshaft of a 30-40 liter 12-18 cyl monster. Not to mention the case when it's (the engine) is full of holes and debris.

IMHO you stop the engine - prop stops with it, feathered or not would only affect the amount of drag it should generate. Anyone knows any different?

(In a dive and other daft conditions it would be possible to turn the engine just by the sheer speed/power of airflow blah-blah-blah. I'm talking about "normal" situation here that is if PFL is ever normal

).

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-lynx-
13 Sqn RAF

Rocket · « **Reply #1 on:** July 18, 2000, 01:50:00 PM »

I have read a story somewhere, and I really wish I could remember where it came from, that the b17 had so much problems with the props they added an electric feather to it. The engine would be shot out and without the feature it would windmill and pickup speed until it came off the engine and if it was an inboard it would come towards the cockpit.
The early B17s could only feather while the engine was running and sometimes there was little time while the pilot and co-pilot were busy with other things to get it feathered.

Remember these are larger props than you find on your local civilian plane and with it set to take a big bite it will operate like a window fan with a slight breeze blowing through it while it is off.

S!
Rocket

-lynx- · « **Reply #2 on:** July 19, 2000, 05:50:00 AM »

Well - there's a small difference between a fan and a prop - the former does not have to turn a crankshaft with 12+ huge pistons attached to it...

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-lynx-
13 Sqn RAF

RAM · « **Reply #3 on:** July 19, 2000, 09:10:00 AM »

But the latter has to deal with an air current of several hundred of mph going thru its blades

But really I feel quite "disturbing"

that when I run out of fuel in my 190 the prop refuses to feather

I know the reduce RPM trick, but is there any way to REALLY feather it at all?

CavemanJ · « **Reply #4 on:** July 19, 2000, 01:31:00 PM »

the way I understand the current setup of the sim is that props that could be feathered are automatically feathered when the engine dies. Props that can't be feathered are not, and you'd better reduce the rpm on your prop before the engine dies (oil/radiator/etc hit) or you've got a helluva drag disc to deal with when it dies.

RAM · « **Reply #5 on:** July 19, 2000, 01:46:00 PM »

well right now if someone comes and kills my 190's engine with a shot, the prop promptly feathers...but when my fuel is out the prop remains windmilling like crazy...

strange isnt it?