Launch Characteristics of the X-15 Research Airplane as Determined in Flight

The first 16 air launches of the X-15 airplane demonstrated the feasibility of air launch from an asymmetric position under the wing of the B-52 carrier airplane. With all dampers operating, launch transients were minimized and no stability problems were encountered. But, when the roll damper failed to function, the X-15 experienced relatively large roll rates in the presence of the carrier airplane, creating the possibility of the X-15 upper vertical tail hitting the cutout in the B-52 wing. Specific flight data demonstrated that left-aileron settings of from 6 deg to 8 deg at launch minimized the right-roll transient. The altitude loss of 3,000 to 9,000 feet before climbout could be effected was a function of launch altitude and recovery angle of attack. The average time for the X-15 to separate 10 feet from the B-52 carrier airplane was about 0.8 second. Flight-measured separation rates and launch transients agree well with predicted values where the initial conditions and control motions are similar.