F-16 touches 110` angle-of-attack
								
By Guy Norris in Los Angeles

   A Lockheed F-16 equiped with a General Electric thrust-vectoring nozzle
has achived a transient angle of attack (AoA) of 110` and a sustained AoA of
80`.
  Programme sources say the high tranisent AoA was attained during emulation
of the "Cobra: manoeuvre which "...made the Sukhoi Su-27 look boring". The
tests are being undertaken as part of the US Air Force's multi axis
thrust-vectoring (MATV) project,in which the effect of picth/yaw
thrust-vectoring on combat capabilities and high AoA characteristics is
being assessed.
	The two-seat testbed F-16 is the specially adapted variable-stability
inflight simulator aircraft (VISTA),fitted with a GE F110-100 engine and
pitch/yaw axisymmetric vectoring engine nozzle (AVEN).More than 30h of a
test programme of about 116h have already been amassed.The first 25h were
dedicated to subsonic high manoeuvrability tests at altitudes starting at
30000 ft (9200 m).
   A low-altitude phase,covering,work in the 20000-25000 ft area of the
flight envelope,began in mid-August and should be completed around
mid-October.This phase also examines the performance of the engine under
high AoA conditions.
   "The engine is performing flawlessly with no stalls or afterburner
blow-outs," says the engine maker.The USAF adds:"We could have expected at
least some sort of 'pop' stall,but it has been fine,even when we have taken
air up the tail pipe during the Cobra."
   Concurrent with envelope expansion during phase two,the MATV programme is
also expected to move to a third phase covering the military utility of the
AVEN nozzle.Pilots from the test team as well as from the 416th test
squadron at Edwards AFB,and the 422nd test and evaluation squadron,based at
Nellis AFB,Nevada,will fly the aircraft against the conventional F-16s in
simulated combat conditions.
   MATV programme officials hope the AVEN nozzle can be used by the pilots
to demonstrate several new combat techniques including an unusual evasive
maneouvre called the "hammer-head",wich forces the pursuing aircraft to
overshoot.
   Other exercises to be attempted will include a gun-tracking rates,
allowing an aircraft to track an opponent inside his turning circle;and a
moneouvre known as a "J turn",calling for decelerations from 300 kt to
around 0 tk in 5-10 s.
   The programme is expected to be completed by the end of November so that
the aircraft can be returned to the VISTA configuration by 1 January next
year.

                     Preuzeto iz Flight International , 8-14 Septebmer 1993