1. #1
    Is there a list of optimal glide speeds for the planes in IL-2 somewhere?
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  2. #2
    The_Stealth_Owl's Avatar Banned
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    I could probably tell some if you name the planes you want to know about.
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  3. #3
    WTE_Galway's Avatar Senior Member
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    It's going to be very close to or in many cases identical with the best climb speed.
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  4. #4
    AndyJWest's Avatar Senior Member
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    Originally posted by WTE_Galway:
    It's going to be very close to or in many cases identical with the best climb speed.
    That is my understanding too. There are really two 'optimal' speeds: one giving the shallowest angle of descent, and the other (a bit slower I think, but probably not much) giving the slowest rate of descent.

    If you do lose an engine and have to glide (rather than bailing, which can sometimes be more sensible) you should convert any excess speed you have into height, with a gentle climb, until you approach the best glide speed. If you need to make a turn, keep it gentle. close radiators to minimise drag. Unless you can land on a runway, keep the wheels up and belly-land. Pick a spot clear of obstructions and flat. Landing parallel to, and close by, a river will usually provide flat ground.
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  5. #5
    na85's Avatar Senior Member
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    Originally posted by AndyJWest:

    That is my understanding too. There are really two 'optimal' speeds: one giving the shallowest angle of descent, and the other (a bit slower I think, but probably not much) giving the slowest rate of descent.
    I don't think descent angle is something you want to optimize. In an engine failure or no fuel situation what you're looking for is slowest descent rate, regardless of angle, and the slowest descent rate occurs only at L/Dmax (i.e. minimum drag speed)
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  6. #6
    Actually, you would want to optimize the descent angle. Your objective is to get as far as you can. It doesn't matter how fast you are dropping towards the ground, as long as you get the greatest range.

    Stealth Owl. Couldn't you just point me to the source of that information?
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  7. #7
    I don't think descent angle is something you want to optimize. In an engine failure or no fuel situation what you're looking for is slowest descent rate, regardless of angle, and the slowest descent rate occurs only at L/Dmax (i.e. minimum drag speed)
    Not quite:

    As you want to make the largest distance with your altitude avaliable (maybe reaching an airfiled..), you're looking for glide-angle in the first place.

    L/D-max is the speed of the shallowest glide-angle.
    Lmax is the speed of lowest descent-rate.

    The first buys you distance to the ground-contact, the latter buys you time to the ground-contact.

    Chose wisely.
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  8. #8
    Tully__'s Avatar Global Moderator
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    Originally posted by na85:
    <BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by AndyJWest:

    That is my understanding too. There are really two 'optimal' speeds: one giving the shallowest angle of descent, and the other (a bit slower I think, but probably not much) giving the slowest rate of descent.
    I don't think descent angle is something you want to optimize. In an engine failure or no fuel situation what you're looking for is slowest descent rate, regardless of angle, and the slowest descent rate occurs only at L/Dmax (i.e. minimum drag speed) </div></BLOCKQUOTE>

    Pigeon and Brems have it right, if you're after the longest distance to touch down you want shallowest angle of glide. Andy's description of the procedure on engine out is pretty good. There's some good stuff on the topic at http://www.av8n.com/how/htm/aoa.html#sec-ias-aoa
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  9. #9
    Superb site, thanks Tully!
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  10. #10
    The other night I was in a P-51 and out of ammo and there was still one more He111 on target for my airfield at about 500M. I chopped his elevator with my prop. He crashed and I was in glide mode with inop engine about three miles from the airstrip. I trimmed it to about 180 KPH and closed the radiator. I thought I would make it and I kept gear and flaps up as long as I could but I still came up short and landed next to some RR tracks and nosed over but did'nt flip. Too bad you can't dump fuel.
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