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1993-05-08
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Lockheed, Boeing, General Dynamics YF-22A
Don Gazdik [70673,466]
-Files Included
YF-22A__.SIM Aircraft Sim file
YF-22A__ Visual design for Aircraft
YF-22ASO.SIM Source Sim I used
YF-22A.AFX AFX file for AAF
-History
The ATF (Advanced Tactical Fighter) program is the Air Force's designated
successor to the F-15. The design incorporates several new features,
most importantly Supercruise. Supercruise is supersonic speeds at
military power, current fighters must use afterburners for supersonic
travel which consumes fuel at a very high rate. Lockheed was awarded
the contract to produce the F-22 in April of 1991. Production is
expected to start in late 1997 and last through 2015. Current plans call
for a total of 648 aircraft for the Air Force.
-Specs
Engines 2 Pratt & Whitney YF119 with two dimensional vectored
thrust producing about 35,000 lbs thrust in afterburner each Maximum
Takeoff Weight Unknown
Combat Takeoff Weight Approx 62,000 lbs
Empty Weight Approx 34,000 lbs
Fuel Capacity Approx 25,000 lbs (internal)
Length 64.2 ft
Height 17.7 ft
Wingspan 43.0 ft
Wing Area 830 sq ft
Aspect Ratio 2.23
Max Speed > Mach 2.5 at 100% Military Power
> Mach 3 at Full Afterburner
Operational Ceiling > 80,000 ft
-Flying the YF-22A
This seems to be a relatively unstable design to me.
The only notes I wanted to make here are that the flaps do add
some lift, but with much drag, spoilers only add drag.
The design is also capable of full elevator turns at most speeds
as long as elevator is not added too quickly.
-Design Notes
This is my second AAF design (the first was just something to get
the feel of designing with AAF) and first serious aircraft sim.
I had a very tough time getting low speed manuverability with this
design. The only way I found to get the manuverability indicated
(one test pilot remarked that the YF-22 could maneuver at high mach
"as well as other aircraft do subsonically") was to give both the
main wings and elevators about a 2.5 degree angle of incidence,
this has the unfortunate side effect of forcing the aircraft to fly
in a nose down posistion to maintain a steady altitude.
If anybody has any other methods to get low speed manuverability
(Besides changing the aspect ratio of the wings, that ratio is
required to make the plane steady at mach 1.5+) I would really love
to hear them. The aircraft also is instable at speeds greater than
about 1100 KTAS, the design starts pitching wildly, so if you have
any ideas on that I'd like to hear them also.
-Information Source
Many issues of Aviation Week and Space Technology