From: joep@neon.dfrf.nasa.gov (Joe Pahle)
Subject: Re: Request for info: NASA HARV and X-31 programmes
Reply-To: joep@neon.dfrf.nasa.gov
Organization: NASA Ames-Dryden FRF, Edwards, CA
Date: Tue, 26 Jan 1993 19:18:06 GMT

In article <2834@eagle.ukc.ac.uk>, rdd@ukc.ac.uk (Rudnei Dias da Cunha) writes:
|> Dear readers,
|> 
|> I would like to ask if anybody from NASA could comment on the developments 
|> being made with the HARV programme (which uses a F/A-18 as test-bed), 
|> any modifications made to the aircraft, and if this project relates to the 
|> X-31 programme.
|> 
|> Thanks in advance!
|> 
|> P.S.: Please note the cross-posting...
|> --
|>                                     Rudnei Dias da Cunha
|>                        Computing Lab, University of Kent at Canterbury
|>                           Canterbury, Kent  CT2 7NF, United Kingdom

-- 

Well... I don't really know where to start. Both the HARV and the X-31
are currently flying at NASA Dryden, so you might try the PAO at
Dryden for general project info. Many papers are available on both
programs, and several high-alpha symposia have been held covering the
X-29 high alpha, F-18 HARV, and X-31. As to how the programs relate,
Since they are both being flown here, there is quite a bit of day to
day interaction. The X-31 is an international X program, where the
HARV is NASA driven. Some HARV data is subject to ITAR restrictions, I
don't know of the X-31 data is being restricted in any manner.

I do know something of the HARV, but I can only give you alittle info
on the X-31. 

 The HARV just completed a high-alpha BFM/ACM (basic fighter / air
combat maneuvers) flight test phase, and is currently in an agility
and high-alpha flying qualities phase. Included in the BFM was the
J-turn (modified Herbst-turn, or high alpha reversal, and an offensive
spiral (think of it as a very small-radius flat turn with the velocity
vector pointed down) where the pilot was able to track a target while
at approx. 60 deg alpha !!  The HARV is about to go down for about 5
months for some extensive modifications in aero and propulsion
instrumentation. Later this year, we will be flying flow
visualization, real-time thrust measurements, flight control laws
designed by NASA LaRC, and scheduled for '94 will be flight test of a
forebody strake concept and a non-linear (dynamic inversion) control
law concept.

There are a number of papers that have been written on the A/C mods as
well as the system mods that were made to the F/A-18 to include the
thrust vectoring system and the research flight control system.
Numerous papers have also been presented on the control law concepts
(present and upcoming ...). You can sent me E-mail if you want some
specific topics.

X-31 is currently flying a 2-A/C envelope expansion program, and
should be getting into a BFM/ACM phase soon. The X-31 has demonstrated
maneuvering capability at 70 alpha, where the HARV can only trim to 70
alpha, and maneuver to about 65 alpha. 

Hope this helps ...

Joseph W. Pahle 
F-18 HARV flight controls 
phone: 805 258-3185
e-mail: joep@neon.dfrf.nasa.gov 
UUCP: ames!neon.dfrf.nasa.gov!joep

Standard disclaimer - MY opinions not NASA's.
Comment: disclaimers attract lawyers ... here boy !  
NASA Ames Dryden Flight Research Facility, Edwards,CA