Date: Wed,  2 Dec 92 05:05:47    
From: Space Digest maintainer <digests@isu.isunet.edu>
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Subject: Space Digest V15 #485
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Space Digest                Wed,  2 Dec 92       Volume 15 : Issue 485

Today's Topics:
                         Shuttle replacement

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Date: Wed, 2 Dec 1992 04:30:41 GMT
From: Bruce Dunn <Bruce_Dunn@mindlink.bc.ca>
Subject: Shuttle replacement
Newsgroups: sci.space

Robert J Woodhead writes:


> Autorotation not only works very well, but demonstrating the ability
> to make an autorotation landing is a pre-requisite for a helicopter
> pilot certificate.
>
> There is a very large amount of energy in a spinning heli blade, and
> the principle of autorotation is to maintain that energy while using
> the drag of the blades to maintain a steady (albeit high) rate of

> descent until just before landing, when the rotational energy is
> used to decelerate the heli.
>


        It would be very interesting for this general line of argument to
compare the descent rate of a helicopter in the high rate part of an
unpowered descent with the descent rate of an aerobraked DC-1.  Both vehicles
are falling at a substantial terminal velocity, and have to do a well
controlled maneuver to deaccelerate just before touchdown.  I suspect that
the margins in terms of "hovering time" probably are a bit less tight on the
DC-1.  Since this is apparently a routine maneuver in helicopter training,
this would argue that the rocket powered analog might not be so hard as many
people are making out.
--
Bruce Dunn    Vancouver, Canada   Bruce_Dunn@mindlink.bc.ca

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End of Space Digest Volume 15 : Issue 485
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