YF-23 was an American single-seat, twin-engine stealth fighter aircraft
Two YF-23 prototypes were built, nicknamed “Black Widow II” and “Gray Ghost”.
The YF-23 was stealthier and faster, but less agile than its competitor
After a four-year development and evaluation process, the YF-22 has announced the winner in 1991 and entered production as the Lockheed Martin F-22 Raptor.
The YF-23 was an unconventional-looking aircraft with diamond-shaped wings, a profile with substantial area-ruling to reduce aerodynamic drag at transonic speeds, and an all-moving V-tail.
The cockpit was placed high, near the nose of the aircraft for good visibility for the pilot.
The aircraft featured a tricycle landing gear configuration with a nose landing gear leg and two main landing gear legs.
The weapons bay was placed on the underside of the fuselage between the nose and main landing gear. The cockpit has a center stick and side throttle.
It was powered by two turbofan engines with each in a separate engine nacelle with S-ducts, to shield engine axial compressors from radar waves, on either side of the aircraft’s spine.
Of the two aircraft built, the first YF-23 (PAV-1) was fitted with Pratt & Whitney YF119 engines, while the second (PAV-2) was powered by General Electric YF120 engines.
Most note worthy The aircraft featured fixed engine nozzles, instead of thrust vectoring nozzles as on the YF-22.
As on the B-2, the exhaust from the YF-23’s engines flowed through troughs lined with heat-ablating tiles to dissipate heat and shield the engines from infrared homing (IR) missile detection from below.
Furthermore, The flight control surfaces were controlled by a central management computer system.
Raising the wing flaps and ailerons on one side and lowering them on the other provided roll.
The V-tail fins were angled 50 degrees from the vertical. Pitch was mainly provided by rotating these V-tail fins in opposite directions so their front edges moved together or apart.
In addition, Yaw was primarily supplied by rotating the tail fins in the same direction.
Test pilot Paul Metz stated that the YF-23 had superior high angle of attack (AoA) performance compared to legacy aircraft. Deflecting the wing flaps down and ailerons up on both sides simultaneously provided for aerodynamic braking.
To keep costs low despite the novel design, a number of “commercial off-the-shelf” components were used, including an F-15 nose wheel, F/A-18 main landing gear parts, and the forward cockpit components of the F-15E Strike Eagle