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From: rmiller@i88.isc.com (Richard J. Miller)
Newsgroups: sci.military
Subject: glider towing
Message-ID: <1990Aug28.030635.21400@cbnews.att.com>
Date: 28 Aug 90 03:06:35 GMT
Sender: military@cbnews.att.com (William B. Thacker)
Organization: AT&T Bell Laboratories
Lines: 44
Approved: military@att.att.com



From: rmiller@i88.isc.com (Richard J. Miller)
<From:     Will Martin <wmartin@STL-06SIMA.ARMY.MIL>
...
<What is the effect on the towplane's internal load capacity when it tows a
<glider on takeoff?
<..., but then one realizes that the gliders
<provide their own lift, and support their own weight.  So the towplane just
<has to provide forward momentum. 
<
<But then one thinks about takeoff -- pulling the loaded glider from a dead
<start would have to take the towplane's entire capacity, so it couldn't
<also be carrying its usual load. So then this one, at least, gets
<confused. Do glider-towing bombers or cargo planes fly empty, carry a
<reduced load of ordnance or cargo, or can they carry their full usual
<load in addition to towing the glider? (If the latter, it certainly adds
<to the arguments in favor of gliders! But it sure sounds like a free
<lunch... :-)
<
<Regards, Will

it takes (possibly MUCH) more runway, but there still is no significant
capacity problem with towing. the primary problem was starting the
takeoff roll (as in getting the glider out of the rut it was sitting in)
and then getting up to flying speed (the glider should usually be able
to lift off first, which helps). even the old, flimsy, ugly ones probably
added only a couple hundred pounds of drag (note drag, NOT weight) to
the towplane, which is not real significant considering what they could
carry themselves.

this is, in fact, the exact reason why the US was looking at gliders at
the beginning of WWII, there were simply not enough cargo aircraft
available and gliders provided a easy and cheap way to get more cargo
capability. that problem slowly became less important by the last year
of the war and the disadvantages of gliders such as maneuverability
were being felt more in the missions that were needed. since then the
cargo lifters have gotten faster to the point of making it very
unpleasant to pull something with them!

Rich Miller
Interactive Systems Corporation
rmiller@i88.isc.com
{sun, amdahl, att (maybe)}!laidbak!rmiller