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From: nak%archie@att.att.com (Neil A Kirby)
Newsgroups: sci.military
Subject: Re: F-117A performance?
Message-ID: <1991Feb6.033318.22925@cbnews.att.com>
Date: 6 Feb 91 03:33:18 GMT
References: <1991Jan23.043709.7563@cbnews.att.com> <1991Feb4.065635.21784@cbnews.att.com> <1991Feb5.043703.6484@cbnews.att.com>
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From: nak%archie@att.att.com (Neil A Kirby)
In article <1991Feb5.043703.6484@cbnews.att.com> tkogoma%triton.unm.edu@ariel.unm.edu (Gym Z. Quirk) writes:
>
>
>From: tkogoma%triton.unm.edu@ariel.unm.edu (Gym Z. Quirk)
>In article <1991Feb4.065635.21784@cbnews.att.com> smpod@venus.lerc.nasa.gov (Stefan) writes:
>>In article brooksp@hpcc01.corp.hp.com (Peter Brooks) writes...
>>/I've heard that the nickname for the
>>/117 is the Wobblin' Goblin, but hey, why *should* it be easy
>>/to fly?  The pilots seem pretty happy with its performance..
>
>According to a recent NOVA show on camoflage and stealth technology,
>the F-117 is "...an inherrently unstable aircraft."  Apperantly, the
>on-board computer is required to make the necessary corrections to
>keep the thing flying.  This takes the "fly by wire" concept one step
>further: You tell the computer what you want the plane to do, the
>computer tells the plane how to do it.

Not really.  The F16 is barely stable, and then only in certain parts of
the flight envelope/modes.  The fly by wire system itself has modes, one of
which is slow reacting for inflight refueling.

The X-29 (forward swept wings) is also fly by wire with the computer
providing most of the stability.  The test pilots loved it.

The unclassified data I saw as an Air Force Employee (1980) showed a
roughly parabolic curve [open ends up] intesected by a horizontal line.
Everything below the horizontal line was stable, everything above was
unstable.  The F16's curve was very close to the line, with the computer
providing stability above the line.  The more stable the plane, the harder
it is to manuever.  The F16 is designed to be barely stable to unstable to
make it quicker to maneuver.

The computer is supposed to attention to what the pilot is doing.  For two
manuevers, (high G climbout and high G dive), the computer is supposed to
bring the plane out of them after the pilot blacks out.  Having seen the
NOVA episode where the F16 training mission winds up pointed at the ground
with a blacked out pilot [and an extremely pissed back seat instructor], I
can not say if this software actually exists and/or works.

Neil Kirby