https://en.wikipedia.org/wiki/NASA_AD-1
The NASA AD-1 was both an aircraft and an associated flight test program
conducted between 1979 and 1982 at the NASA Dryden Flight Research Center,
Edwards California, which successfully demonstrated an aircraft wing that could
be pivoted obliquely from zero to 60 degrees during flight.
The unique oblique wing was demonstrated on a small, subsonic jet-powered
research aircraft called the AD-1 (Ames-Dryden-1). The aircraft was flown 79
times during the research program, which evaluated the basic pivot-wing concept
and gathered information on handling qualities and aerodynamics at various
speeds and degrees of pivot.
The first known oblique wing design was the Blohm & Voss P.202, proposed by
Richard Vogt in 1942.
The oblique wing concept was later promoted by Robert T. Jones, an aeronautical
engineer at NASA's Ames Research Center, Moffett Field, California.
Analytical and wind tunnel studies Jones initiated at Ames indicated that a
transport-size oblique-wing aircraft, flying at speeds up to Mach 1.4 (1.4 times
the speed of sound), would have substantially better aerodynamic performance
than aircraft with more conventional wings.
At high speeds, both subsonic and supersonic, the wing would be pivoted at up to
60 degrees to the aircraft's fuselage for better high-speed performance. The
studies showed these angles would decrease aerodynamic drag, permitting
increased speed and longer range with the same fuel expenditure.
At lower speeds, during takeoffs and landings, the wing would be perpendicular
to the fuselage like a conventional wing to provide maximum lift and control
qualities. As the aircraft gained speed, the wing would be pivoted to increase
the oblique angle, thereby reducing the drag and decreasing fuel consumption.
The wing could only be swept in one direction, with the right wingtip moving
forward.
Role
Experimental aircraft
National origin
United States
Manufacturer
Ames Industrial Co.
Designer
Burt Rutan
First flight
21 December 1979
Retired
August 1982
Primary user
NASA
Number built
1
Unit cost
USD $240,000
The research program to validate the oblique wing concept was typical of any
operating envelope, methodically and carefully. The basic purpose of the AD-1
project was to investigate the low-speed characteristics of an oblique-wing
configuration.
The AD-1 made its first flight late in 1979. The wing was pivoted incrementally
over the next 18 months until the full 60-degree angle was reached in mid-1981.
The aircraft continued to be flown for another year, obtaining data at various
speeds and wing-pivot angles until the final flight in August 1982.
The final flight of the AD-1 did not occur at Dryden, however, but at the
Experimental Aircraft Association's (EAA) annual exhibition at Oshkosh,
Wisconsin, where it was flown eight times to demonstrate its unique
configuration.
Thus, although the AD-1 structure allowed completion of the program's technical
objectives, there was still a need for a transonic oblique-wing research
aircraft to assess the effects of compressibility, evaluate a more
representative structure, and analyze flight performance at transonic speeds
(those on either side of the speed of sound).
Specifications
General characteristics
Crew: 1 (pilot)
Length: 38 ft 10 in (11.83 m)
Wingspan: 32 ft 4 in (9.85 m) unswept
Height: 6 ft 9 in (2.06 m)
Wing area: 93 sq ft (8.6 m2)
Airfoil: NACA 3612-02, 40
Empty weight: 1,450 lb (658 kg)
Gross weight: 2,145 lb (973 kg)
Fuel capacity: 80 US gallons (300 l)
Performance
Maximum speed: 200 mph (322 km/h; 174 kn)
Service ceiling: 12,000 ft (3,700 m)
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