Military


F/A-18 Hornet

History

The McDonnell Douglas F/A-18 Hornet traces its direct ancestry to the Northrop Cobra, a twin engine multimission fighter design developed for the export market in the late 1960s. The Cobra was never built in this form. In 1975 the Navy was directed by Congress to base the VFAX on either the YF-16 or YF-17 designs. Two of the companies having a major interest in the VFAX, which was redesignated the Navy Air Combat Fighter, paired with the F-16/17 builders; neither of the latter had experience in producing Navy carrier fighters. Vought as a prime contractor teamed with General Dynamics on a single-engined F-16 derivative, while McDonnell Douglas became the prime, paired with Northrop, on an F-17 derivative.

To meet Navy requirements, considerable improvements in areas such as combat radius and radar capability were incorporated, in addition to carrier suitability features. The resulting redesign was extensive and, when the McDonnell Douglas design was selected as winner in 1976, it was assigned the F-18A designation. The developed versions of the YF-17's YJ101 engines were redesignated F404s. While the general configuration of the YF-17 was retained, the F-18 became a completely new airplane. To meet the single-place fighter and attack mission capability, full use was made of new technology in digital computers. Coupled with cathode ray tubes for cockpit displays and appropriate controls based on thorough pilot evaluations in simulators, a single airplane and subsystems configuration for both missions was evolved

The formidable task of converting the land-based YF-17 lightweight day fighter into an all-weather fighter-attack aircraft capable of carrier operations with heavy ordnance loads required significant changes from the earlier configuration. Structural strengthening and a new landing gear design were required for catapult launches and arrested land-ings. The aircraft gross weight rapidly grew from 23,000 lb for the YF-17 to a projected weight over 33,000 lb.

The required approach speeds for carrier landings resulted in modifications to the wing and leading-edge extension (LEX). surfaces of the YF-17 configuration to provide more lift. Changes were made to the aircraft configuration. The geometric shape of the YF-17 LEX was extended farther forward on the fuselage and the plan view of the LEX was modified to produce additional lift while retaining the good high-angle-of-attack characteristics exhibited by the YF-17. The deflections of the wing leading- and trailing-edge flaps were increased and the aile-rons were programmed to droop in low-speed flight to augment lift. Finally, a "snag" or discontinuity was added to the leading edges of both the wing and horizontal tails to provide more lift.



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