Two of a Special Kind

While most attention has focused on preparations for the manned Apollo flight, last week NASA quietly proceeded with two other pioneering programs --the record-breaking test series of the X-15 and the XB-70, respectively the fastest and the heaviest supersonic aircraft in the world. Ironically, both planes were built by North American Aviation, Inc., the company that has borne much of the blame for the January spacecraft holocaust.

The X-15, which has been probing manned, rocket-powered flight and studying the solar spectrum at the edge of the earth's atmosphere (354,200 ft.), recently set a new speed record of 4,260 m.p.h., or 6.33 times the speed of sound. Last week the once all-black plane sported a white paint job covering new ablative material purposely designed to char in flight as the aircraft engages in tests that should push its maximum speed to a blistering Mach 8 by 1969. Snugged under its wings, the X-15 now carries twin, droppable tanks loaded with additional fuel needed to achieve such speed.

The 500,000-lb. XB-70 on display, virtually a flying aerodynamics laboratory, is the survivor of two prototypes. Needle-nosed, delta-winged and resembling two giant praying mantises, both of the 6-engine jets had attained a speed of Mach 3 in tests. Then the second and more sophisticated of the two crashed in June 1966 after Test Pilot Joe Walker's F-104 Starfighter jet brushed the giant plane's wing, then tore through a rudder during a publicity flight. Since then, tests of XB-70 No. 1 have contributed aerodynamic and thermodynamic knowledge, including studies of the sonic-boom problem that are being used in the development of such heavyweight transports as the SST.

This file is automatically generated by a robot program, so reader's discretion is required.