Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!tut.cis.ohio-state.edu!att!cbnews!military
From: listen@cbnews.ATT.COM
Newsgroups: sci.military
Subject: Re: MiG 23 crash
Message-ID: <8093@cbnews.ATT.COM>
Date: 10 Jul 89 04:20:23 GMT
References: <8028@cbnews.ATT.COM>
Sender: military@cbnews.ATT.COM
Lines: 30
Approved: military@att.att.com



From: listen
>... Does the
>explosive parachute-deployment system work to deploy only the
>chute, or is it hooked to the ejector seat that the pilot sits
>on?  My confusion is, are they two different things, one (the
>ejector seat) for getting the pilot out of the craft, and two
>(the para-deploy system) for getting the chute canapy out of
>the casing before the pilot hits the ground? 

They're two different systems, although they're both part of the ejection
seat as currently packaged.  A modern ejection seat will fire a cartridge
to kick the seat out of the plane, fire rockets to boost it further (in
case of an ejection at very low altitude), and then simultaneously cut
the pilot loose from the seat and fire the parachute (hooked to the pilot,
not to the seat) out of its canister.  The best modern seats use
a cartridge-plus-rocket system for the parachute deployment too, in
fact, to get the chute fully deployed almost instantaneously.  The latest
production seat, the Martin-Baker NACES system for the US Navy, can get
the pilot on the ground safely after an ejection from an aircraft flying
at 100 feet UPSIDE DOWN.  There are experimental "vertical-seeking" seats
that know which way is up and can vector rocket thrust to turn around in
mid-air and head upward, but the NACES seat is not one of them -- it just
gets the parachute out awfully fast at low altitude.  It does measure
altitude and speed as it leaves the plane (using its own sensors), so it
can decide whether panic-mode chute deployment is in order.

                                     Henry Spencer at U of Toronto Zoology
                                 uunet!attcan!utzoo!henry henry@zoo.toronto.edu