Path: utzoo!yunexus!geac!cbs
From: cbs@geac.UUCP (Chris Syed)
Newsgroups: sci.space.shuttle
Subject: Re: Soviet and American Shuttles
Summary: flight
Message-ID: <3435@geac.UUCP>
Date: 18 Oct 88 12:56:51 GMT
Article-I.D.: geac.3435
References: <1574@nunki.usc.edu> <3020@jpl-devvax.JPL.NASA.GOV> <1703@eos.UUCP> <29318@think.UUCP>
Distribution: sci.space.shuttle,sci.space
Organization: Geac Computers, Markham, Ontario Canada
Lines: 38

In article <29318@think.UUCP>, craig@think.COM (Craig Stanfill) writes:
> 
> It doesn't require thrust to sustain altitude or climb, it requires
> VEOLCITY.

    Well... as I recall from 101, there are four forces acting on an
    aircraft:
                               ^
                             lift
                    < thrust         drag >
                             weight
                               V

    It would be more correct to say that _lift_ is required. Lift
    is produced by the velocity of the air passing over the airfoil,
    which has to be greater than the velocity of air passing under the
    airfoil to create a pressure difference). You get this effect in part
    by the aircraft's speed, and in part by the curvature of the wing
    and its angle of attack. If you tip the wing up, you get more lift.
    If you tip it too much, you stall.

    To get better lift at low velocities, most aircraft extend their wing
    surfaces and change their lift-producing characteristics by using flaps,
    (the jumbos use Fowler flaps which are almost big enough to be considered
    'second wings'), and by using a high angle of attack. Many designs also
    incorporate "leading edge devices" to produce more lift at low airspeeds.
    Of course, the flaps are also meant to decrease the speed of the craft
    by inducing more drag. 

    The shuttle dosen't have enormous flaps, (at least I don't think so).
    This means you must rely on speed, natural characteristics of the wings,
    and the angle of attack to get your lift on final approach.

          {uunet!mnetor,unicus,yunexus,}!geac!cbs (Chris Syed)