| Model |
Manufacturer |
Pop |
Tenure |
Flights |
|
X-1
X-1A
X-1B
X-1D
X-1E
|
Bell |
3
1
1
1
1
|
1946-1951
1953-1955
1954-1958
1951
1955-1958
|
157
25
27
1
26
|
First Mach 1+
First controlled-reaction
Mach 2.24 |
| X-2 | Bell |
2 |
1952-1956 |
20 |
Mach 2.87 at 126,200' |
| X-3 | Douglas |
1 |
1954-1956 |
20 |
Inertia coupling |
| X-4 | Northrop |
2 |
1950-1953 |
82 |
Semi-tailless transonic |
| X-5 | Bell |
2 |
1952-1955 |
133 |
Variable wing tests |
| X-6 | Genl Dynamics |
0 |
1955-1957 |
0 |
B-36 shield tests |
| X-7 | Lockheed |
61
|
1951-1960
|
61
|
Ramjet tests
|
| X-8 | Aerojet Engr |
74 |
1947-1956 |
74 |
Upper-air research |
| X-9 | Bell |
31 |
1949-1953 |
28 |
Unmanned ASM |
| X-10 | North American |
13 |
1955-1959 |
15 |
Unmanned |
| X-11 | Convair |
8 |
1956-1958 |
8 |
Unmanned ICBM |
| X-12 | Convair |
5 |
1958 |
5 |
Unmanned ICBM |
| X-13 | Ryan |
2 |
1955-1957 |
|
First VTOL |
| X-14 | Bell |
1 |
1957-1981 |
|
VTOL |
| X-15 | North American |
3 |
1959-1968 |
199 |
First supersonic |
| X-16 | Bell |
0 |
c.1956 |
|
Canceled; mock-up only |
| X-17 | Lockheed |
26 |
1955-1957 |
26 |
Unmanned re-entry vehicle |
| X-18 | Hiller |
1 |
1959-1961 |
20 |
First tilt-wing VTOL |
| X-19 | Curtiss-Wright |
2 |
1964-1965 |
50 |
Dual tandem tilt-prop |
| X-20 | Boeing |
0 |
|
|
Canceled Dyna-Soar |
| X-21A | Northrop |
2 |
1963-1964 |
|
Boundary-layer tests |
| X-22A | Bell |
2 |
1966-1984 |
501 |
Ducted-fan VTOL |
| X-23A | Martin |
4 |
1966-1967 |
3 |
Re-entry vehicle |
X-24A
X-24B | Martin |
1
(1) |
1969-1975 |
64 |
Lifting body
Modified X-24A |
X-25
X-25A
X-25B | Bensen |
1
1
1 |
1968
19??
19?? |
|
Descent vehicles |
X-26A
X-26B | Schweizer |
6 |
1967-1988 |
|
Stealth tests |
| X-27 | Lockheed |
0 |
1970 |
|
Canceled |
| X-28A | Pereira Osprey |
1 |
1971 |
|
|
| X-29A | Grumman |
2 |
1984-1990 |
302 |
Forward-swept wing |
| X-30 | Boeing/MSU |
0 |
1990 |
|
Canceled hypersonic |
| X-31A | Rockwell |
2 |
1990-1995 |
523 |
Tailless technology |
X-32A
X-32B | Boeing |
1
1 |
2000-> |
|
JSF fighter |
| X-33 | Lockheed-Martin |
0 |
1998 |
|
Advanced Tech demo |
| X-34 | Orbital Sciences |
2 |
1998 |
|
Technology test-bed |
| X-35 | Lockheed-Martin |
2 |
2000-> |
|
JSF fighter |
| X-36 | McDonnell-Douglas |
1 |
1994-> |
|
Tailless research vehicle |
| X-37 | NASA / Boeing / USAF |
|
2002-> |
|
Orbital test vehicle |
| X-38 | SCALED Inc |
2-3 |
1996-> |
|
Space crew return vehicle |
| X-39 | USAF Research Lab |
|
| |
Future technology |
| X-40A | Boeing |
1 |
19??-> |
7 |
Unmanned space vehicle |
| X-41 | USAF Research Lab |
|
(2003) |
|
Reusable spaceplane |
| X-42 | USAF Research Lab |
|
20?? |
|
Rocket upper-stage |
| X-43A | NASA |
3 |
2001-> |
|
Unmanned hypersonic "scramjet"
designed for 7,000 mph speeds |
| X-44 | Lockheed |
|
|
|
Possibly cancelled |
| X-45A | Boeing |
1 |
2001-> |
|
Unmanned combat vehicle; ff: 7/11/01 |
| X-46 | Boeing |
|
2000-> |
|
USN version of X-45 |
| X-47A | Northrop-Grumman |
1 |
19??-> |
|
Unmanned combat vehicle |
| X-48A | NASA / Langley |
|
|
|
Subscale blended-wing project |
| X-48B | NASA / Boeing |
|
2006-> |
|
Blended-wing body |
| X-49 | |
|
|
|
|
| X-50A | Boeing |
2 |
2002 |
|
CRW VTOL? |
