Ames-Dryden-1

It looks like something out of the latest futuristic Hollywood blockbuster.

But this rather odd-looking plane is in fact more than 30 years old.

Developed by Nasa in the 1970s, the AD-1 - or Ames-Dryden-1 - was a research aircraft designed to investigate the concept of a pivoting wing.

Airborne for just four years between 1979 and 1982, it was only flown 79 times.

Retro futurism: Developed by Nasa in the 1970s, the AD-1 was a research aircraft designed to investigate the concept of a pivoting wing

Skewed concept: The AD-1 was the brainchild of Nasa aeronautical engineer Robert T Jones

The AD-1's oblique wing could be rotated on its centre pivot.

It remained perpendicular to the fuselage during slow flight and swinging to angles of up to 60 degrees as aircraft speed increased.

This allowed scientists to set it at the most efficient angle for the speed at which the plane was flying.

Also called the 'scissors' wing, it was an offshoot of the variable-sweep wing concept, which was first investigated with X-5 research planes during the early 1950s.

A variable-sweep wing allows an aircraft to take advantage of the lift and handling qualities of a fixed wing during the comparatively slow flight of take-offs and landings.

It also allowed for the better efficiency of the more traditionally swept-back wings during high speeds and cruise speeds.

The AD-1 was the brainchild of Nasa aeronautical engineer Robert T Jones.

The AD-1's oblique wing could be rotated on its centre pivot. It remained perpendicular to the fuselage during slow flight and swinging to angles of up to 60 degrees as aircraft speed increased

Cockpit: Airborne for just four years between 1979 and 1982, it was only flown 79 times

Working at the Nasa Ames Research Center in Moffet Field, California, his analytical and wind tunnel studies indicated that with an oblique wing, supersonic transport might achieve twice the fuel economy of an aircraft sporting more conventional wings.

The concept was first evaluated by a small, propeller-driven, remotely-piloted research vehicle flown at Dryden in 1976.

These early techniques for gathering data about the oblique wing aircraft were applied to the twin turbojet, piloted AD-1, which was flown from 1979 to 1982.

Variable-sweep wings are common on many high performance aircraft, including the F-14, F-111 and B-1.

Although the oblique wing is still considered a viable concept for large transports, the unpleasant flying characteristics of the AD-1 at extreme wing-sweep angles may have discouraged aircraft designers from adopting this configuration.