Northrop X-21
| Northrop X-21 | |
|---|---|
 Northrop X-21A at Edwards AFB , 1962 |
|
| Type: | Experimental airplane |
| Design country: | |
| Manufacturer: | |
| First flight: |
April 18, 1963 |
| Commissioning: |
Flight tests ended in 1968 |
| Production time: |
Was never mass-produced |
| Number of pieces: |
2 |
The Northrop X-21A was an American experimental aircraft .
It was intended to investigate ways of influencing the boundary layer flow on a wing in order to reduce air resistance and thus increase the range.
The two machines were created by converting Douglas WB-66D weather observation aircraft (s / n 55-0408 and 55-0410). The existing jet engines of the type Allison J71 were against General Electric J79 replaced 13-GE engines and moved to the rear to the air flow on the wings can not be influenced.
The newly designed wings had a larger span and wing area than the B-66. Tiny grooves were milled across the entire span from which the air was sucked out in order to delay the transition from laminar to turbulent boundary layer and thereby reduce drag. The air was extracted by two turbines, which were housed in fairings under the wings and were driven by bleed air from the J79 engines. The sucked air was blown out of nozzles on the wing tips and thus generated additional thrust .
The crew consisted of a pilot and two flight engineers. Two other flight engineers were housed in a fuselage shaft below the wings.
The first flight took place on April 18, 1963. However, due to the extreme susceptibility of the grooves to dirt and icing, the project was discontinued in 1964.
Both X-21A's are being kept at Edwards Air Force Base , California, where they can be viewed in an unrestored condition.
Technical specifications
| Parameter | Data |
|---|---|
| crew | 5 |
| length | 23.0 m |
| span | 28.5 m |
| Max. Takeoff mass | 37,700 kg |
| Top speed | 900 km / h |
| Engines | General Electric J79 |
Web links
Individual evidence
- ↑ Description on history.nasa.gov p. 28. (PDF; 1.2 MB) Retrieved on February 11, 2013 .
- ^ Inventory list of the Air Force Flight Test Museum at Edwards Air Force Base. Archived from the original on December 15, 2016 ; accessed on December 15, 2016 .