posted 09-06-2020 05:09 AM               

Space Cover #576: The M2-F2 and F3 Lifting Body

This week's Space Cover of the Week was metered on July 12, 1966, the day that the M2-F2 first flew. The meter was done at the Northrop plant in Hawthorne, CA where the M2-F2 was manufactured. The cachet was printed by the Northrop Stamp Club.

We've looked at other lifting body shapes like the "potato shaped" SV-5 in SCOTW 558 and the "airfoil shaped" HL-10 in SCOTW 567. There was another "half-cone" or "bathtub" shape that first flew as the plywood M2-F1, towed behind a souped-up Pontiac or a C-47 cargo plane as described in SCOTWs 20 and 134.

The success of the M2-F1 "lightweight" lifting body prompted NASA to contract with the Northrop Corporation to build one M2-F2 aircraft, similar in shape to the M2-F1, but made of metal, with fully retractable landing gear, a complex control system, small landing rocket motors, and provisions to add an XLR11 rocket engine to propel the M2-F2 to supersonic speeds. The M2-F2 would be launched from under the wing of a B-52 bomber, much like the X-15.

The M2-F2 was rolled out of the Northrop plant on June 15, 1965 and delivered to Edwards AFB the next day. The first captive flight was performed on March 23, 1966. The M2-F2 completed its first glide flight on July 12, 1966 (as commemorated on the cover above) with Milt Thompson at the controls. The M2-F2 flew 13 more glide flights through November 21, 1966 in the hands of Thompson, Bruce Peterson, Jerry Gentry, and Don Sorlie. NASA then grounded the M2-F2 for installation of its rocket engine. On May 2, 1967, the M2-F2 made a glide flight with the engine installed, piloted by Jerry Gentry.

Up to this point, the M2-F2 had shown a tendency to go into a rolling motion during certain portions of flight, but the pilots could damp this motion out by raising the nose of the aircraft. On the next flight (cover pictured above), May 10, 1967, pilot Bruce Peterson encountered the rolling motion at 6000 feet altitude. By the time he damped out the motion, he was too low to land at the targeted point on the lakebed. Then one of the rescue helicopters flew across Peterson's path, causing further distractions. Amid all the distractions, the landing gear did not get fully extended by the time the M2-F2 touched down. It tumbled violently across the dry lakebed, finally stopping upside down. Peterson survived but was severely injured. Film of the crash exists and was commonly seen as the opening for the '70's television series, "The Six Million Dollar Man".

The broken M2-F2 was trucked back to the Northrop plant to be repaired and modified to fix the rolling problem. The fix was to add a third vertical fin, and this version was designated the M2-F3. The M2-F3 made its first glide flight on June 2, 1970 with Bill Dana at the controls. The rolling problem was fixed, and the M2-F3 embarked on a rocket powered flight program to test the extent of the lifting body's capability. On August 25, 1971 Dana performed the craft's first flight faster-than-sound as commemorated on the Space Voyager Cachet cover above. On December 13, 1972 Dana and the M2-F3 reached over 1.6 times the speed-of-sound, the record for the M2 series. During the last flight of the M2-F3 on December 20, 1972, John Manke flew to 71,500 ft altitude, (over 13 miles), the highest ever for the M2 series.

M2-F2 event covers exist for all the flights but tend to be hard-to-find. M2-F3 event covers exist for all the flights, with covers for the July 23, 1971 and subsequent flights being easy to find.

Covers were also known to have been carried on multiple M2-F3 missions, including Manke's first flight, October 19, 1972 (see above).

The M2-F3 is presently on display in the Smithsonian Air and Space Museum in Washington, DC.