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From: stevenp@decwrl.pa.dec.com (Steven Philipson)
Newsgroups: sci.military
Subject: Re: a10 in combat
Message-ID: <1991Mar14.015445.19658@cbnews.att.com>
Date: 14 Mar 91 01:54:45 GMT
References: <1991Feb13.222209.6649@cbnews.att.com> <1991Feb9.025209.29262@cbnews.att.com> <1991Feb11.043245.27178@cbnews.att.com>
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From: stevenp@decwrl.pa.dec.com (Steven Philipson)
In article <1991Feb13.222209.6649@cbnews.att.com>, tohall@helios.lerc.nasa.gov
   (Dave Hall (Sverdrup)) writes;
 
  [re: firing a Sidewinder backwards]
 
> As a matter of fact, you need to change the laws of physics governing
> the mechanics of flight. When the missile came off, it would have to
> reduce its forward velocity to zero, then accelerate in the opposite
> direction.  [...]

    It is not necessary to change the laws of physics to accomplish such
a rearward launch.  The missile would need some additional hardware,
but it wouldn't be particularly difficult to build.

   The primary addition to existing missiles would be a second set of fins.
An additional rocket booster section would probably be added as well.  The
second, larger set of fins would be used to stabilize the missile while it
is flying in the direction of flight of the launching aircraft.  The
additional booster section would decelerate the missile.  The fins would
be jettisoned as the missile transitioned through zero airspeed, i.e. as
it reversed its direction of flight.  The normal fins would then be used
in forward flight as the missile accelerated toward its target.

   This technology appeared in print in the 1960's, by one G. Harry
Stein, in a handbook on *model* rocketry.  A two stage model was
described as follows (this is from memory, and may not be entirely as
it was described in the book).  Two rocket bodies are assembled coaxially,
with the second stage having a smaller set of fins than the primary stage.
The first stage would launch the assembly, coast through apogee, then nose
over till pointed down.  (The velocity vector is now pointed at the
ground.)  The second stage would then fire on a delayed fuse, stabilized
in launch by the body of the first stage, and by its own fins after
separation.  This was done with a few dollars worth of hardware and no
gyros.

   I wouldn't be at all surprised to see such backward firing missiles
built, albeit more advanced control devices, including gyro stabilization,
thrust vectoring, reaction controls, and deployable fins.

						   Steve
					(the certified flying fanatic)
					    stevenp@decwrl.dec.com