Aces High Bulletin Board
General Forums => Aircraft and Vehicles => Topic started by: tommygun on March 18, 2008, 04:14:23 PM
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What is the command to feather the prop. I get my engine shot out from time to time and need to get back to base with the best glide speed.
Thanks
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I believe it's the - key on the keypad.
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Not all can be feathered. Your best bet is to reduce RPM to the minimum level. If the prop is still spinning you can do this.
If it's totally dead (siezed up, not spinning) you won't be able to adjust it.
Engines that can feather do so automatically when you shut them down. Look at P-38s, B-17s, and so forth. Usually only the multi-engine planes.
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Not all can be feathered. Your best bet is to reduce RPM to the minimum level. If the prop is still spinning you can do this.
If it's totally dead (siezed up, not spinning) you won't be able to adjust it.
Engines that can feather do so automatically when you shut them down. Look at P-38s, B-17s, and so forth. Usually only the multi-engine planes.
That last statement is wrong i think, the first two are correct. Engines don't automatically feather when you shut them off on multi engine planes AFAIK.
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What is the command to feather the prop. I get my engine shot out from time to time and need to get back to base with the best glide speed.
Thanks
If your engine is still running, run full out, WEP on and gain as much speed as possible. Once the motor is completely dead, I'm not sure you can pull the RPM back as I believe the RPM goes to zero anyway. To get the best bang for your buck, level off until your indicated air speed is approximately equal to the alt-x climb speed of the aircraft, and then hit alt-x. The default alt-x climb speed is pretty close to best glide speed, and will compensate for any sloppiness caused by trying to hand fly it back to base deadstick. Obviously, if you're on the deck, this won't work, but even at medium altitude, you can plan on gliding almost a full sector if you have a full head of steam and use best glide speed the whole way down. Just make sure you don't engage alt-x until after you have slowed to roughly the same speed, or you'll blow your excess energy on a climb that's not going to do much for you ultimately.
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Dropping RPM definitely works when your engine is dead but the prop is still spinning.
If the prop is spinning, you can slow it down.
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Typically I reduce RPM to minimum then shut the engine off before it seizes up. The prop will just windmill on it's own with reduced drag as opposed to being stopped. I can glide rather far provided I adjust trim manually as I glide. I find if the engine seizes up then the prop blades act as nice brakes and the glide length is shortened.
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Dropping RPM definitely works when your engine is dead but the prop is still spinning.
Like you wouldnt believe! Its an AMAZING difference!
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Dropping RPM definitely works when your engine is dead but the prop is still spinning.
I think he was talking about what to do if it was shot out, and not if he just shut it down.
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If his engine is shot out and is siezed up for whatever reason and the prop is not windmilling then they might as well be airbrakes. If it suffers an oil or radiator hit, reduce RPM to minimum and shut it down, the prop will be feathered and you can glide nicely.
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That last statement is wrong i think, the first two are correct. Engines don't automatically feather when you shut them off on multi engine planes AFAIK.
Try it :aok
There's a difference between feathering the prop and reducing drag on a prop. Fully feathering it turns the blades into the wind, and the prop stops spinning. Check it out on a B-17 and a P-38, for example.
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Try it :aok
There's a difference between feathering the prop and reducing drag on a prop. Fully feathering it turns the blades into the wind, and the prop stops spinning. Check it out on a B-17 and a P-38, for example.
Shutting down engine 1 on the P-38J doesn't feather the prop for me. The prop has pitch, but it isn't feathered (which is turning the blades completely into the wind). Does it do that for you? If so, anything special you do to achieve it?
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There seems to be some confusion in these discussions..
Multi-engine aircraft: Props self feather if the engine(s) quits due to damage of a lack of fuel. Manually shutting off an engine does not cause it to feather. You can set the set the prop at high pitch manually to minimize drag, but the prop will continue to windmill.
Single-engine aricraft: Props do not feather. You can set high pitch to minimize drag, but the prop will always windmill.
Graphically, the visual pitch of the prop never changes, even when feathered. Nonetheless, the drag factor is changed with pitch.
My regards,
Widewing
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(+) and (-) keys
Kamori
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Shutting down engine 1 on the P-38J doesn't feather the prop for me. The prop has pitch, but it isn't feathered (which is turning the blades completely into the wind). Does it do that for you? If so, anything special you do to achieve it?
It only happens when your engine shuts due to lack of fuel and battle damage. Turning off the engine manually will not feather the props.
ack-ack
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If his engine is shot out and is siezed up for whatever reason and the prop is not windmilling then they might as well be airbrakes.
False. A stationary prop, even with blades completely perpendicular to airflow, still generates significantly less drag than a windmilling prop at any speed. This is half the reason the ability to feather props on multi-engine aircraft was introduced. The other reason being that a windmilling prop on a dead engine can result in self-destruction of the engine, or the dead engine and prop deciding to part ways spontaneously.
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Hmmm, double-posted while trying to fix something. Odd
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The other reason being that a windmilling prop on a dead engine can result in self-destruction of the engine, or the dead engine and prop deciding to part ways spontaneously.
Not in this game.
And in the game a dead prop is an air-brake. You're better off with it windmilling at minimum RPM.
Short story: I got shot up one night with a radiator leak. I was low alt with two+ sectors to get home. I put it on auto climb until the engine temp climbed into the red-line (at ~7K), then leveled, shut the engine off, reduced RPM to minimum and set glide speed for 150 mph. When I reached 2K I powered up, bumped RPM all the way up and hit auto climb until the temp went into the red-line then repeated the process. I repeated the entire thing probably 10 times and made it home to land safely but it took quite awhile.
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Oops... accidently quoted myself again.
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Not in this game.
And in the game a dead prop is an air-brake. You're better off with it windmilling at minimum RPM.
Short story: I got shot up one night with a radiator leak. I was low alt with two+ sectors to get home. I put it on auto climb until the engine temp climbed into the red-line (at ~7K), then leveled, shut the engine off, reduced RPM to minimum and set glide speed for 150 mph. When I reached 2K I powered up, bumped RPM all the way up and hit auto climb until the temp went into the red-line then repeated the process. I repeated the entire thing probably 10 times and made it home to land safely but it took quite awhile.
Actually, indeed in this game, and easily verifiable. I just did the following but five minutes ago:
1> Take a P-38, Mossie, or other multi-engine (as these have auto-feathering props).
2> Take off, set autoclimb, climb to a pre-determined altitude.
3> Once at that pre-determined altitude, DO NOT TURN OFF AUTOCLIMB. Instead, simply pull the throttle back to idle, keeping prop RPM at max. Record decent rate once it stabilizes.
4> Climb to previously determined altitude, and repeat this test with engines idling at low RPM-setting, and engines shut down (feathered).
The results will be as follows: Highest decent-rate will be with props spinning at high RPM. This is because, due to the high drag, the 'autoclimb' autopilot will need to pitch the aircraft down farther to maintain the set airspeed. The lowest decent rate, will be props stopped, with props spinning at low RPM being a bit worse for decent-rate, but not close to the rate with the props spinning at high RPM.
Conclusion: The faster the prop is spinning, the higher the drag it generates, and a stopped-prop creates the lowest drag. Even in this here game with its cartoon airplanes.
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What is the command to feather the prop. I get my engine shot out from time to time and need to get back to base with the best glide speed.
Thanks
if i recall, the engine rpm is controlled by the prop pitch(angle of the blades) and the manifold presure is controlled by the throttle(how far opened the butterfly is on the air inlet). so..if your engine is dead, i think you can still use the minus key on the numeric keypad...and i think this is what feathers the prop. i think the p38 does it automaticaly, but i htink the spits don't........
hope this helps some
<<S>>
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And in the game a dead prop is an air-brake. You're better off with it windmilling at minimum RPM.
Not in the P-38 or any other multi-engine plane. As already stated, if the engine is shut down due to lack of fuel or battle damage it will automatically feather when it quits.
ack-ack
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The prop on single engined fighters can be stopped by going to zero airspeed. This can be accomplished by going vertical until stalled. Good luck on recovering.
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The prop on single engined fighters can be stopped by going to zero airspeed. This can be accomplished by going vertical until stalled. Good luck on recovering.
nose down, let her re-gain flying speed. stall recovered :aok
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Not in the P-38 or any other multi-engine plane. As already stated, if the engine is shut down due to lack of fuel or battle damage it will automatically feather when it quits.
ack-ack
I was talking about single engine planes. I don't fly multi-engine planes all that much to have noticed.