North American YF-93

YF-93

Picture - The first YF-93A with NACA inlets

Role: Fighter
Manufacturer: North American Aviation
First flight: 24 January 1950
Introduced: Experimental
Retired: 1956
Primaryusers: United States Air Force NACA
Number built: 2
Unit cost: US$11.5 million for the program
Developed from: F-86 Sabre

Picture - Top view of the second YF-93

The North American YF-93 was an American fighter development of the F-86 Sabre that emerged as a radically different variant that received its own designation. Two were built and flown, but the project was eventually canceled.

Design and development

In 1947, North American Aviation began a design study, NA-157, to create a true "penetration fighter" to meet the requirements of a long-range version of its F-86A Sabre. In order to accommodate more fuel, a much larger F-86A was envisioned, eventually able to carry 1,961US gallons (7,420 l), both internally and with two 200-US-gallon (760 l) underwing drop tanks. The new variant possessed a theoretical unrefuelled range of over 2,000nmi (2,300 mi; 3,700 km), twice that of the standard production F-86A. The resultant fighter originally designated the F-86C was intended to compete with the XF-88 Voodoo and Lockheed XF-90 to fulfill the USAF's Penetration Fighter requirement for a bomber escort.

The F-86C was much larger and heavier, weighing in at 10,640lb (4,830 kg) more than its antecedent. The increased weight and girth necessitated a dual-wheel main landing gear, increased wing area and a more powerful J48 rated at 6,250lbf (27.8 kN) static thrust, with 8,750lbf (38.9 kN) thrust available in afterburner. With the SCR-720 search radar and six 20mm (.79in) cannon mounted in the nose where the air intake was on the F-86A, the engineers designed a novel set of flush-mounted NACA inlets. A "wasp waist" was also incorporated in the fuselage.

In December 1947, the Air Force ordered two prototype NA-157s and, considering the many changes to the F-86, redesignated it YF-93A. The first prototype was built with the NACA inlet ducts; the second aircraft had more conventional intakes. Six months later, the initial contract was followed up with an order for 118 F-93A-NAs. In 1949, the production order was abruptly canceled as priorities had shifted dramatically following the testing of the ground-breaking Boeing B-47 which reputedly would not need an escort due to its high speed capabilities. With the prototype YF-93As just coming off the production line, the USAF took over the project.

Operational history

Picture - The first YF-93 in flight

The prototypes, serial numbers 48-317 and -318, began flight tests in 1950 and were entered in a flyoff against the other penetration fighter projects, the XF-88 and XF-90; the XF-88 Voodoo was declared the winner. None of the projects would be ordered. The YF-93As were turned over to the National Advisory Committee for Aeronautics (NACA) AMES facility for further testing before being utilized as chase aircraft until 1956. Flight with the NACA ducts proved troublesome at high angles of attack, restricting air flow to the engines. By this time, however, higher performance aircraft were available and both aircraft were eventually declared surplus and scrapped.

Operators

United States

United States Air Force

Specifications (YF-93A)

Picture - Cut-away illustration of the YF-93A.

General characteristics

Crew: One
Length: 44 ft 1 in (13.44 m)
Wingspan: 38 ft 9 in (11.81 m)
Height: 15 ft 8 in (4.78 m)
Wing area: 306 ft² (28.4 m²)
Empty weight: 14,035 lb (6,366 kg)
Loaded weight: 21,610 lb (9,800 kg)
Powerplant: 1x— Pratt & Whitney J48-P-6 turbojet, 8,750 lbf (38.9 kN)

Performance

Maximum speed: 708 mph (1,132 km/h)
Range: 2,000 mi (3,200 km)
Service ceiling: 46,800 ft (14,268 m)
Rate of climb: 11,960 ft/min (60.8 m/s)
Wing loading: 71 lb/ft² (345 kg/m²)
Thrust/weight: 0.4

Armament

6 x— 20 mm (.79 in) cannon (proposed, not fitted to the prototypes)

Related development

F-86 Sabre

Bibliography

Davis, Larry. F-86 Sabre in action. Carrollton, Texas: Squadron/Signal Publications, 1992. ISBN 0-89747-282-9.
Pace, Steve. X-Fighters: USAF Experimental and Prototype Fighters, XP-59 to YF-23. Osceola, Wisconsin: Motorbooks International, 1991. ISBN 0-87938-540-5.
Sgarlato, Nico and Franco Ragni. U.S. Fighters of the Fifties. Carrollton, Texas: Squadron/Signal Publications, 1979. ISBN 0-89747-090-7.
Wagner, Ray. The North American Sabre. London: Macdonald, 1963. No ISBN.

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Source: WikiPedia