| X-21 | |
|---|---|
 Northrop X-21A | |
| General information | |
| Type | Experimental aircraft |
| Manufacturer | Northrop |
| Primary user | National Aeronautics and Space Administration (NASA) |
| Number built | 2 |
| History | |
| Introduction date | Experimental |
| First flight | 18 April 1963 |
| Retired | 1968 |
| Developed from | Douglas B-66 Destroyer |
The Northrop X-21A was an experimental aircraft designed to test wings with laminar flow control. It was based on the Douglas WB-66D airframe, with the wing-mounted engines moved to the rear fuselage and making space for air compressors. The aircraft first flew on 18 April 1963 with NASA test pilot Jack Wells at the controls.[1] Although useful testing was accomplished, the extensive maintenance requirements of the intricate laminar-flow system caused the end of the program.
- ^ American X-Vehicles: An Inventory, June 2003. Retrieved: 13 February 2007.