Northrop X-21A
Northrop · United States · first flew 1963 · light aircraft
The Northrop X-21A was an American laminar flow control research aircraft converted from the Douglas WB-66 Destroyer, used to investigate whether suction through spanwise slots in the wing surface could maintain laminar airflow at high speeds and thus dramatically reduce aerodynamic drag.
Recognition (WEFT)
| W — Wings | Low-mounted, swept |
|---|---|
| E — Engines | 2 × turbojet, fuselage-mounted |
| F — Fuselage | Two jet engines mounted in the rear fuselage with wing-root intakes |
| T — Tail | Conventional |
WEFT is AircraftIQ's four-point recognition method — how it works.
Spot it by:
- Laminar flow control research aircraft derived from the Douglas WB-66
- Slots and suction ducts in the wing surface to maintain laminar boundary layer
- Two jet engines mounted in the rear fuselage with wing-root intakes
Resembles the Douglas B-66 Destroyer externally but with a distinctive wing surface covered in fine spanwise suction slots; the large wing-root engine intakes and twin engines in the rear fuselage pods are shared with the parent type.
Specifications
- The Northrop X-21A has a length of 22.94 m (75 ft).
- It has a wingspan of 28.51 m (94 ft).
- Its maximum speed is 896 km/h (557 mph).
- Typical crew: 2.
Figures are for the representative variant described above; marks differ. See how AircraftIQ sources figures.
History
First flown in April 1963, the X-21A conducted extensive research at Edwards Air Force Base and demonstrated that laminar flow control was technically achievable, achieving laminar flow over 75% of the wing surface. The technology proved difficult and expensive to implement in practical aircraft and was not adopted for production types.
Variants
Two aircraft were converted from WB-66 airframes; both operated as X-21A research aircraft with no production follow-on.
Where you'll see it
Operated solely by the USAF and Northrop for research at Edwards AFB; no operational service.
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