Sunday, February 06, 2011

On testing planes on rockets:

Over the years, I've seen numerous photos of what appeared to be models of aircraft attached to rockets (ref: Photos of odd, interesting, vintage rockets).  One reader (R2K) posed the question of why rockets were used instead of wind tunnels.  Well, I ran across this quote in  "Oral Histories From the Pioneers of America's Space Program, Part 2" by Dr. Davis-Floyd (U.Texas) and Dr. Cox (NASA JSC).  I'm just noting it 'for the record.'
NACA’s role during this period was to carry out research that would advance aircraft design and to pass its discoveries on to the military or the aircraft industry. Purser and Gilruth put Thibodaux to work on rocket propulsion; Faget got busy designing ramjets--jet engines that take air in at the front, heat it, and spew it out the rear fast enough for a plane to travel supersonically. His job was to see if he could make one thin enough to fit inside the wing of an airplane, and he came up with one a mere six and a half inches in diameter; it later powered a test aircraft to an altitude of 65,000 feet and a speed that exceeded Mach 3.

Thibodaux began by designing rockets to be used for launching aerodynamic scale models of supersonic aircraft at Wallops Island, a barrier island about 85 miles northeast of Norfolk. NACA had established the Wallops Island range because Langley’s conventional wind tunnels choked up and became unusable at what are known as transonic speeds--speeds just above and just below the speed of sound.

- “Annals of Space: Max Faget and Caldwell Johnson,” by Henry S.F. Cooper, The New Yorker, Sept. 2, 1991, pp. 41-69.