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The NASA M2-F1 is a lightweight, unpowered prototype aircraft, developed to flight-test the wingless lifting body concept. Its unusual appearance earned it the nickname "flying bathtub" and was designated the M2-F1, the M referring to "manned", and F referring to "flight" version. In 1962, NASA Dryden management approved a program to build a lightweight, unpowered lifting-body prototype. It featured a plywood shell placed over a tubular steel frame crafted at Dryden. Construction was completed in 1963.
Development
The lifting-body concept originated in the mid-1950s at the National Advisory Committee for Aeronautics' Ames Aeronautical Laboratory, Mountain View, California. By February 1962, a series of possible shapes had been developed, and R. Dale Reed was working to gain support for a research vehicle.
The construction of the M2-F1 was a joint effort by Dryden and a local glider manufacturer, the Briegleb Glider Company. The budget was US$30,000. NASA craftsmen and engineers built the tubular steel interior frame. Its mahogany plywood shell was handmade by Gus Briegleb and company. Ernie Lowder, a NASA craftsman who had worked on Howard Hughes's H-4 Hercules ("Spruce Goose"), was assigned to help Briegleb.
Final assembly of the remaining components (including aluminum tail surfaces, pushrod controls, and landing gear from a Cessna 150, later replaced by Cessna 180 landing gear) was done at the NASA facility.
The wingless, lifting-body aircraft design was initially conceived as a means of landing a spacecraft horizontally after atmospheric reentry. The absence of wings would make the extreme heat of reentry less damaging to the vehicle. Rather than using a ballistic reentry trajectory like a Command Module, very limited in maneuvering range, a lifting-body vehicle had a landing footprint the size of California.<!--dead link-->
Tow testing
right|thumb|The M2-F1 and its 1963 [[Pontiac (automobile)|Pontiac convertible tow vehicle]]
The first flight tests of the M2-F1 were at Rogers Dry Lake, at the end of a tow rope attached to a 1963 Pontiac Catalina convertible. On April 5, 1963 test pilot Milt Thompson lifted the M2-F1's nose off the ground for the first time while being towed.-->
After looking at movies of the tests, it was decided that the bouncing was probably caused by unwanted rudder movements. The control system was modified so that the joystick controlled the elevons rather than the rudder, which solved the problem.<!--dead link-->
It was found that the car used to tow the aircraft was not powerful enough to lift the M2-F1 entirely off the ground, so the FRC arranged to have the tow car hot-rodded by Bill Straub: the modifications tuned the engine for increased power, added a rollbar, and turned the front passenger seat to face aft so the passenger could observe the aircraft. This proved successful, and tow tests continued.
Flight testing
A NASA R4D, the Navy designation for the Douglas DC-3, was used for all of the air tows. The first was on August 16, 1963. The M2-F1 had recently been equipped with an ejection seat and small rockets – referred to by the test team as "instant L/D"
Specifications
thumb|right|300px|NASA M2-F1 lifting-body diagram
Flights
{| class="wikitable" style="background-color:white"
|- style="background:#efefef;"
! Vehicle<br>Flight #
! Date
! Pilot
! Duration
! Velocity<br>(km/h)
! Altitude<br>(m)
! Comments
|-
| M2-F1 #0
| March 1, 1963
| Thompson
| -
| 135
| 0
| First Ground Tow.<br>400 total ground tows.
|-
| M2-F1 #1
| August 16, 1963
| Thompson
| 0:02:00
| 240
| 3,650
| First M2-F1 Flight. 77 total flights.
|-
| M2-F1 #2
| August 28, 1963
| Thompson
| 0:02:09
| 240
| 3,650
| -
|-
| M2-F1 #3
| August 29, 1963
| Thompson
| 0:02:25
| 240
| 3,650
| -
|-
| M2-F1 #4
| August 30, 1963
| Thompson
| 0:04:42
| 240
| 3,650
| 1st flight of day
|-
| M2-F1 #5
| August 30, 1963
| Thompson
| -
| 240
| 3,650
| 2nd flight of day
|-
| M2-F1 #6
| September 3, 1963
| Thompson
| 0:04:50
| 240
| 3,650
| 1st flight of day
|-
| M2-F1 #7
| September 3, 1963
| Thompson
| -
| 240
| 3,650
| 2nd flight of day
|-
| M2-F1 #8
| October 7, 1963
| Thompson
| 0:01:26
| 240
| 3,650
| -
|-
| M2-F1 #9
| October 9, 1963
| Thompson
| 0:01:51
| 240
| 3,650
| -
|-
| M2-F1 #10
| October 15, 1963
| Thompson
| 0:02:20
| 240
| 3,650
| -
|-
| M2-F1 #11
| October 23, 1963
| Thompson
| 0:03:00
| 240
| 3,650
| -
|-
| M2-F1 #12
| October 25, 1963
| Thompson
| 0:03:52
| 240
| 3,650
| 1st flight of the day
|-
| M2-F1 #13
| October 25, 1963
| Thompson
| -
| 240
| 3,650
| 2nd flight of the day
|-
| M2-F1 #14
| November 8, 1963
| Thompson
| 0:07:45
| 240
| 3,650
| 1st flight of the day
|-
| M2-F1 #15
| November 8, 1963
| Thompson
| -
| 240
| 3,650
| 2nd flight of the day
|-
| M2-F1 #16
| November 8, 1963
| Thompson
| -
| 240
| 3,650
| 3rd flight of the day
|-
| M2-F1 #17
| December 3, 1963
| Thompson
| 0:01:00
| 240
| 3,650
| -
|-
| M2-F1 #18
| December 3, 1963
| Yeager
| 0:01:35
| 240
| 3,650
| -
|-
| M2-F1 #19
| December 3, 1963
| Peterson
| 0:03:15
| 240
| 3,650
| 1st flight of the day
|-
| M2-F1 #20
| December 3, 1963
| Peterson
| -
| 240
| 3,650
| 2nd flight of the day<br>Broke landing gear
|-
| M2-F1 #21
| January 29, 1964
| Thompson
| -
| 240
| 3,650
| 1st flight of the day
|-
| M2-F1 #22
| January 29, 1964
| Thompson
| -
| 240
| 3,650
| 2nd flight of the day
|-
| M2-F1 #23
| January 29, 1964
| Peterson
| 0:04:44
| 240
| 3,650
| 1st flight of the day
|-
| M2-F1 #24
| January 29, 1964
| Peterson
| -
| 240
| 3,650
| 2nd flight of the day
|-
| M2-F1 #25
| January 29, 1964
| Yeager
| -
| 240
| 3,650
| 1st flight of the day
|-
| M2-F1 #26
| January 29, 1964
| Yeager
| -
| 240
| 3,650
| 2nd flight of the day
|-
| M2-F1 #27
| January 30, 1964
| Yeager
| -
| 240
| 3,650
| 1st flight of the day
|-
| M2-F1 #28
| January 30, 1964
| Yeager
| -
| 240
| 3,650
| 2nd flight of the day
|-
| M2-F1 #29
| January 30, 1964
| Mallick
| -
| 240
| 3,650
| 1st flight of the day
|-
| M2-F1 #30
| January 30, 1964
| Mallick
| -
| 240
| 3,650
| 2nd flight of the day
|-
| M2-F1 #31
| February 28, 1964
| Thompson
| -
| 240
| 3,650
| 1st flight of the day
|-
| M2-F1 #32
| February 28, 1964
| Thompson
| -
| 240
| 3,650
| 2nd flight of the day
|-
| M2-F1 #33
| March 30, 1964
| Peterson
| 0:02:25
| 240
| 3,650
| -
|-
| M2-F1 #34
| April 9, 1964
| Thompson
| -
| 240
| 3,650
| 1st flight of the day
|-
| M2-F1 #35
| April 9, 1964
| Thompson
| -
| 240
| 3,650
| 2nd flight of the day
|-
| M2-F1 #36
| April 9, 1964
| Peterson
| 0:08:00
| 240
| 3,650
| 1st flight of the day
|-
| M2-F1 #37
| April 9, 1964
| Peterson
| -
| 240
| 3,650
| 2nd flight of the day
|-
| M2-F1 #38
| April 9, 1964
| Peterson
| -
| 240
| 3,650
| 3rd flight of the day
|-
| M2-F1 #39
| May 19, 1964
| Peterson
| 0:04:08
| 240
| 3,650
| 1st flight of the day
|-
| M2-F1 #40
| May 19, 1964
| Peterson
| -
| 240
| 3,650
| 2nd flight of the day
|-
| M2-F1 #41
| June 3, 1964
| Thompson
| -
| 240
| 3,650
| -
|-
| M2-F1 #42
| July 24, 1964
| Peterson
| 0:06:50
| 240
| 3,650
| 1st flight of the day
|-
| M2-F1 #43
| July 24, 1964
| Peterson
| -
| 240
| 3,650
| 2nd flight of the day
|-
| M2-F1 #44
| July 24, 1964
| Peterson
| -
| 240
| 3,650
| 3rd flight of the day
|-
| M2-F1 #45
| August 18, 1964
| Thompson
| -
| 240
| 3,650
| -
|-
| M2-F1 #46
| August 21, 1964
| Thompson
| -
| 240
| 3,650
| 1st flight of the day
|-
| M2-F1 #47
| August 21, 1964
| Thompson
| -
| 240
| 3,650
| 2nd flight of the day
|-
| M2-F1 #48
| August 21, 1964
| Thompson
| -
| 240
| 3,650
| 3rd flight of the day
|-
| M2-F1 #49
| August 21, 1964
| Thompson
| -
| 240
| 3,650
| 4th flight of the day
|-
| M2-F1 #50
| February 16, 1965
| Thompson
| -
| 240
| 3,650
| -
|-
| M2-F1 #51
| May 27, 1965
| Thompson
| -
| 240
| 3,650
| 1st flight of the day
|-
| M2-F1 #52
| May 27, 1965
| Thompson
| -
| 240
| 3,650
| 2nd flight of the day
|-
| M2-F1 #53
| May 27, 1965
| Thompson
| -
| 240
| 3,650
| 3rd flight of the day
|-
| M2-F1 #54
| May 27, 1965
| Thompson
| -
| 240
| 3,650
| 4th flight of the day
|-
| M2-F1 #55
| May 27, 1965
| Sorlie
| 0:06:00
| 240
| 3,650
| 1st flight of the day
|-
| M2-F1 #56
| May 27, 1965
| Sorlie
| -
| 240
| 3,650
| 2nd flight of the day
|-
| M2-F1 #57
| May 27, 1965
| Sorlie
| -
| 240
| 3,650
| 3rd flight of the day
|-
| M2-F1 #58
| May 28, 1965
| Thompson
| -
| 240
| 3,650
| -
|-
| M2-F1 #59
| May 28, 1965
| Sorlie
| 0:04:30
| 240
| 3,650
| 1st flight of the day
|-
| M2-F1 #60
| May 28, 1965
| Sorlie
| -
| 240
| 3,650
| 2nd flight of the day
|-
| M2-F1 #61
| July 16, 1965
| Thompson
| -
| 240
| 3,650
| -
|-
| M2-F1 #62
| July 16, 1965
| Dana
| -
| 240
| 3,650
| -
|-
| M2-F1 #63
| July 16, 1965
| Gentry
| 0:00:09
| 200
| 10
| Rolled M2-F1 on liftoff.<br>Recovered. Safe landing.
|-
| M2-F1 #64
| August 30, 1965
| Thompson
| -
| 240
| 3,650
| 1st flight of the day
|-
| M2-F1 #65
| August 30, 1965
| Thompson
| -
| 240
| 3,650
| 2nd flight of the day
|-
| M2-F1 #66
| August 30, 1965
| Thompson
| -
| 240
| 3,650
| 3rd flight of the day
|-
| M2-F1 #67
| August 31, 1965
| Thompson
| -
| 240
| 3,650
| -
|-
| M2-F1 #68
| October 6, 1965
| Thompson
| -
| 240
| 3,650
| 1st flight of the day
|-
| M2-F1 #69
| October 6, 1965
| Thompson
| -
| 240
| 3,650
| 2nd flight of the day
|-
| M2-F1 #70
| October 8, 1965
| Thompson
| -
| 240
| 3,650
| -
|-
| M2-F1 #71
| March 28, 1966
| Thompson
| -
| 240
| 3,650
| 1st flight of the day
|-
| M2-F1 #72
| March 28, 1966
| Thompson
| -
| 240
| 3,650
| 2nd flight of the day
|-
| M2-F1 #73
| August 4, 1966
| Peterson
| 0:02:00
| 240
| 3,650
| -
|-
| M2-F1 #74
| August 5, 1966
| Peterson
| 0:04:00
| 240
| 3,650
| 1st flight of the day
|-
| M2-F1 #75
| August 5, 1966
| Peterson
| -
| 240
| 3,650
| 2nd flight of the day
|-
| M2-F1 #76
| August 5, 1966
| Peterson
| -
| 240
| 3,650
| 3rd flight of the day
|-
| M2-F1 #77
| August 16, 1966
| Gentry
| -
| 200
| 10
| Rolled M2-F1 on liftoff. Recovered.<br>Fired landing rockets.<br>Safe landing. Last flight.
|}