Air International 1994-12
D.Baker - From ATF to Lightning II. A Bolt in Anger (1)
Publicly unveiled on August 29, 1990, the first of two Lockheed YF-22A pre-production aircraft revealed a very different design approach to the Northrop competitor, with seemingly more conservative design options hiding a highly sophisticated aircraft.
Lockheed ATF Concept
Lockheed revealed this early configuration in October 1985, employing canards and 2-D thrust vectoring nozzles for manoeuvrability.
Launched from the underwing pylon of a Boeing B-52, HiMAT advanced the data base on high g transonic agility using canard and high-lift surfaces controlled from the ground by a NASA test pilot.
Making its first flight on May 10, 1989, the F-15B S/MTD demonstrator was equipped with a digital fly-by-wire control system, modified engines with 2-D nozzles and canards.
Seen head-on, the YF-23 exhibits features first applied to the Lockheed SR-71, with chines from the front of the radome back to the wing leading edge.
Northrop/McDonnell Douglas YF-23. Фирма "Northrop" полагала, что ключом к победе является высокая скорость и малозаметность. YF-23 в избытке обладал этими качествами - с двигателями General Electric YF120 он мог совершать крейсерский полет на скорости М=1,8 без использования форсажа.
Самолет имел в плане контуры, образованные прямыми линиями, - практически все они были параллельны передней или задней кромке крыла (исключая законцовки крыла и нижнюю переднюю часть фюзеляжа), а кромки всех створок и основных панелей обшивки имели зигзагообразную форму. Эти и другие решения позволили снизить заметность машины в радиолокационном диапазоне.
Seen in plan the YF-23A displays its unusual over-tail exhaust arrangement with a single serration for breaking radar returns. Note the small ailerons and large flaps, and parallel leading and trailing edges of wing and tail.
This view illustrates the smooth lines and high-set cockpit affording an excellent frontal view for the pilot.
Its length accentuated by the large overhanging tail surfaces, the Northrop-McDonnell Douglas YF-23A is rolled out to public view for the first time on June 22, 1990.
Both the side and plan elevations are graphically displayed in this view of the two YF-23A prototypes 87-0800 and 87-0801. The slender wing-blended fuselage is particularly worthy of note.
With trapezoidal underwing intakes and overwing engine-exhaust geometry, the YF-23A adopts multi/conipound-curvature to match low observable technology with an agile supercruise performance.
In searching for an F-15 replacement with quantum steps in agility and supercruise manoeuvring, manufacturers explored a wide variety of design and technology options. This Boeing concept features over-wing inlets for low IR visibility, a two-crew cockpit and large tail surfaces for flick-turns.
Boeing moved a step back to the future with this early ATF design incorporating a coupled delta-canard configuration but with an unstealthy fin and recessed missile bay displaying good radar return characteristics.
Supercruise performance demanded low bypass engines in a streamlined aerodynamic configuration. This concept emphasised sheer performance but with little agility or supersonic manoeuvrability.