Time Period: Post-WW2
Country of Origin: United States
Type: Prototypes and Experimental
Manufacturer: Ames Industrial Co., NASA
NASA AD-1 Aircraft Overview
If you ever saw a plane flying with its wing at a wild diagonal angle and thought it looked broken, there’s a good chance you were looking at the NASA AD-1. This experimental aircraft from the late 1970s and early ’80s was created to test a bold aerodynamic concept: the oblique wing.
The AD-1 (Ames-Dryden 1) was an experimental aircraft developed by NASA to explore the idea of a pivoting wing that could change its angle mid-flight. Unlike traditional swept-wing aircraft, which keep both wings angled symmetrically, the AD-1 featured a single rigid wing that rotated diagonally across the fuselage—think of it as flying with one wing forward and the other swept back.
At full tilt, the wing could reach an angle of 60 degrees, which looked almost comically askew but served a very real aerodynamic purpose: reducing drag at high speeds and improving fuel efficiency in cruise flight.
Why Build It?
The concept of the oblique wing was first proposed by aeronautical engineer Robert T. Jones, who theorized that a wing mounted at an angle could improve transonic and supersonic performance while remaining structurally simple. NASA wanted to test this theory in real-world conditions, and the AD-1 was the first manned aircraft to bring it to life.
How Did It Perform?
The AD-1 first flew in 1979 and carried out over 70 test flights until its retirement in 1982. It handled well at small sweep angles, but at high angles, pilots reported serious handling issues—like wing flexing and aeroelastic distortion—that made the aircraft unstable.
Despite its limitations, the AD-1 fulfilled its mission: it proved that the oblique wing concept could work and paved the way for further studies in advanced aerodynamics.
How Did It Perform?
The AD-1 was retired after completing its test program. The extreme wing angles created too many stability issues for practical use, and by then, other aerodynamic advancements (and materials) were taking center stage. Still, the AD-1 became a symbol of NASA’s boundary-pushing approach to flight research.
Today, the AD-1 is preserved and on display at the Hiller Aviation Museum in California, where you can see its famously skewed wing frozen mid-sweep—a testament to just how far engineers will go to explore the future of flight.
NASA AD-1 Specifications
- Crew: 1 (pilot)
- Length: 38 feet (11.58 meters)
- Wingspan (unswept): 32 feet (9.75 meters)
- Height: 7 feet (2.13 meters)
- Maximum Takeoff Weight: Around 2,145 lbs (973 kg)
- Powerplant: 2 × Microturbo TRS-18 turbojets, producing 220 lbf (980 N) thrust each.
NASA AD-1 Performance
- Maximum speed: 200 mph (320 km/h, 170 kn)
- Service ceiling: 12,000 ft (3,700 m)
