The May 1967 crash of the M2-F2 had damaged both the external skin and the internal structure of the lifting body. At first, it seemed that the vehicle had been irreparably damaged, but the original manufacturer, Northrop, did the repair work. After a three-year-long redesign and rebuilding effort, the M2-F3 was ready to fly. The redesigned M2-F3 was fitted with a center fin for stability.
The first flight of the M2-F3, with NASA pilot Bill Dana at the controls, was on June 2, 1970. It was a glide flight to evaluate changes in the vehicle's performance due to the modifications. The modified vehicle exhibited much better lateral stability and control characteristics than had the M2-F2.
Over the next 26 missions, the M2-F3 reached a top speed of 1,064 mph (Mach 1.6). Bill Dana was the pilot, and the high-speed flight took place on December 13, 1972. The highest altitude reached by the vehicle was 71,500 feet on December 21, 1972, the date of its last flight, with NASA pilot John Manke at the controls.
A reaction jet control system, similar to thrusters used on orbiting spacecraft, was also installed to obtain research data about their effectiveness for vehicle control. As the M2-F3's portion of the lifting body program neared an end, it evaluated a rate command augmentation control system, and a side-arm control stick similar to side-arm controllers now used on many modern aircraft.
The M2-F3 is now on display in the National Air and Space Museum, Washington, D. C.
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