Northrop M2-F2

M2-F2
Role	Lifting body Technology Demonstrator
National origin	United States
Manufacturer	Northrop
First flight	12 July 1966
Retired	10 May 1967
Status	Rebuilt as M2-F3
Primary user	NASA
Number built	1
Developed from	NASA M2-F1
Variants	Northrop M2-F3

The Northrop M2-F2 was a heavyweight lifting body based on studies at NASA's Ames and Langley research centers. Built by the Northrop Corporation in 1966. The "M" refers to "manned" and "F" refers to "flight" version.

Development

The success of Dryden's M2-F1 program led to NASA's development and construction of two heavyweight lifting bodies based on studies at NASA's Ames and Langley research centers—the M2-F2 and the HL-10, both built by the Northrop Corporation. The "M" refers to "manned" and "F" refers to "flight" version. "HL" comes from "horizontal landing" and 10 is for the tenth lifting body model to be investigated by Langley. (See also NASA Ames Research Center).

The M2-F2 made its first captive flight (attached to the B-52 carrier aircraft throughout the flight) on March 23, 1966.

The first flight of the M2-F2 - which looked much like the "M2-F1" - was on July 12, 1966. Milton O. Thompson was the pilot.

By then, the same B-52 used to air launch the famed X-15 rocket research aircraft was modified to also carry the lifting bodies. Thompson was dropped from the B-52's wing pylon mount at an altitude of 45,000 feet (13,700 m) on that maiden glide flight. He reached a gliding speed of about 450 miles per hour (720 km/h).

Operational history

The crash site of the M2-F2

Before powered flights were undertaken, a series of glide flights were conducted. On May 10, 1967, the sixteenth and last glide flight ended in disaster as the vehicle slammed into the lake bed on landing. With test pilot Bruce Peterson at the controls, the M2-F2 suffered a pilot induced oscillation (PIO) as it neared the lake bed. At the core of this problem was the fact that the wings of the M2-F2 (essentially the body of the aircraft) produced considerably less roll authority than most aircraft. This resulted in less force availible to the pilot to control the aircraft in roll. As a consequence, when Bruce attempted to perform roll maneuvers the response of the vehicle was substantially less than expected, thus lending to a "soft" feel for this control which often leads to PIO in the roll axis. (Source: interview with Bruce Peterson, 1980) The vehicle rolled from side to side in flight as he tried to bring it under control. Peterson recovered, but then observed a rescue helicopter that seemed to pose a collision threat. Distracted, Peterson drifted in a cross-wind to an unmarked area of the lake bed where it was very difficult to judge the height over the ground because of a lack of guidance (the markers provided on the lake bed runway).

Peterson fired the landing rockets to provide additional lift, but he hit the lake bed before the landing gear was fully down and locked. The M2-F2 rolled over six times, coming to rest upside down. Pulled from the vehicle by Jay King and Joseph Huxman, Peterson was rushed to the base hospital, transferred to March Air Force Base and then the UCLA Hospital. He recovered but lost vision in his right eye due to a staphylococcal infection.

Portions of M2-F2 footage including Peterson's spectacular crash landing were used for the 1973 TV movie The Six Million Dollar Man though some shots during the opening credits of the series showed the later HL-10 model, during release from its carrier plane, a modified B-52.

Four pilots flew the M2-F2 on its 16 glide flights. They were Milton O. Thompson (5 flights), Bruce Peterson (3 flights), Don Sorlie (3 flights) and Jerry Gentry (5 flights).

NASA pilots and researchers realized the M2-F2 had lateral control problems, even though it had a stability augmentation control system. When the M2-F2 was rebuilt at Dryden and redesignated the M2-F3, it was modified with an additional third vertical fin -- centered between the tip fins to improve control characteristics.

The M2-F2/F3 was the first of the heavy-weight, entry-configuration lifting bodies. Its successful development as a research test vehicle answered many of the generic questions about these vehicles.

M2-F2 flights

• NASA M2-F2 - NASA 803, 16 unpowered flights

Vehicle Flight #	Date	Pilot	Mach	Velocity (km/h)	Altitude (meters)	Duration	Comments
M2-F2 #1	July 12, 1966	Thompson	0.646	727	13,716	00:03:37	First M2-F2 Flight. Unpowered glide. 320 km/h landing.
M2-F2 #2	July 19, 1966	Thompson	0.598	634	13,716	00:04:05	Unpowered glide. Determination of lateral stability control, longitudinal trim, vehicle performance and landing characteristics.
M2-F2 #3	August 12, 1966	Thompson	0.619	692	13,716	00:04:38	Unpowered glide. Determine effect of increasing Mach number, minimum damper requirements, testing of longitudinal and lateral stability and control.
M2-F2 #4	August 24, 1966	Thompson	0.676	718	13,716	00:04:01	Unpowered glide. Determine control damper requirements, lift-drag ratio, elevon response, flap effectiveness and longitudinal stability and control.
M2-F2 #5	September 2, 1966	Thompson	0.707	750	13,716	00:03:46	Unpowered glide. Evaluate 360 degree overhead approach, determine control damper-off handling qualities.
M2-F2 #6	September 15, 1966	Peterson	0.705	750	13,716	00:03:30	Unpowered glide. Pilot checkout.
M2-F2 #7	September 20, 1966	Sorlie	0.635	678	13,716	00:03:31	Unpowered glide. Pilot checkout.
M2-F2 #8	September 22, 1966	Peterson	0.661	702	13,716	00:03:53	Unpowered glide. Longitudinal and lateral stability and control with dampers.
M2-F2 #9	September 28, 1966	Sorlie	0.672	713	13,716	00:03:53	Unpowered glide. Complete pilot checkout and extend flight envelope.
M2-F2 #10	October 5, 1966	Sorlie	0.615	692	13,716	00:03:45	Unpowered glide. Explore lateral and longitudinal stability and control characteristics with dampers on and off.
M2-F2 #11	October 12, 1966	Gentry	0.662	702	13,716	00:03:54	Unpowered glide. Pilot checkout.
M2-F2 #12	October 26, 1966	Gentry	0.605	642	13,716	00:03:47	Unpowered glide. Obtain stability and control data at 7 and 11 degree attack angles and upper flap effectiveness.
M2-F2 #13	November 14, 1966	Gentry	0.681	716	13,716	00:04:21	Unpowered glide. Test stability and control, determine vehicle performance characteristics.
M2-F2 #14	November 21, 1966	Gentry	0.695	735	13,716	00:03:50	Unpowered glide. Test stability and control, determine vehicle performance characteristics.
M2-F2 #15	May 2, 1967	Gentry	0.623	661	13,716	00:03:51	Unpowered glide.
M2-F2 #16	May 10, 1967	Peterson	0.612	649	13,716	00:03:43	Unpowered glide Crash landing

Specifications (M2-F2)

General characteristics

• Crew: one, pilot
• Length: 22 ft 2 in (6.76 m)
• Wingspan: 9 ft 8 in (2.94 m)
• Height: 9 ft 6 in (2.89 m)
• Wing area: 160 ft² (14.9 m²)
• Empty weight: 4,620 lb (2,095 kg)
• Loaded weight: 6,000 lb (2,722 kg)
• Max takeoff weight: 7,485 lb (3,395 kg)
• Powerplant: 1 × Reaction Motors Upgraded XLR-11 four-chamber rocket engine, 8,000 lbf (36 kN)

Performance

• Maximum speed: Mach 0.707 (466 mph, 750 km/h)
• Range: 8.6 nm (10 mi, 16 km)
• Service ceiling: 45,000 ft (13,700 m)
• Wing loading: 43.2 lb/ft² (196 kg/m²)
• Thrust/weight: 1.3

See also

Aircraft of comparable role, configuration and era

• X-24
• M2-F1
• M2-F3
• HL-10
  

External links

• Most of text taken from NASA Dryden webpage.
• NASA Dryden M2-F2 Photo Collection
• NASA Dryden M2-F2 Video Collection
• Wingless Flight: The Lifting Body Story. NASA History Series SP-4220 1997 PDF
• Video of Peterson's crash