May 2, 1963

TO : Chief, Research Division

FROM : Aerospace Engineer, Veh. and Sys. Dynamics Branch

SUBJECT : Preliminary Evaluation of X-15 Flight 1-33-54

Flight 1-33-54 was flown on April 11, 1963, by Major Bob Rushworth for the purposes of:

KC-1 camera tests

APU checkout

Preliminary results indicate all objects were accomplished.

The launch was made in the vicinity of Hidden Hills at an altitude of 45,000 feet and the flight was completed as planned. The launch configuration for the flight was ventral off, both BCS ~on", RAS "off", ASAS "armed" and SAS gain settings P(6), R(4), Y(8). The maximum altitude for the flight was approximately 73,000 feet and a maximum velocity of approximately 4,100 ft/sec.

The preflight SAS and ASAS checks were accomplished without any problem occurring in the stability augmentation system.

Immediately after launch the normal roll SAS channel malfunctioned and the ASAS came on. The pilot reset the roll channel and re-engaged the normal SAS and no other SAS malfunction occurred during the remainder of the flight.

The SAS electronics assembly has been thoroughly ground tested and has met all the required specifications. A special test was conducted to determine if a malfunction in the system caused the tripout. As a result of these tests, it is believed that a malfunction of the system did not occur during the flight. The roll tripout occurring during the flight appears to be similar to previous tripouts which was due to the solid state switching network that is susceptible to transients. An explanation for the tripout is a transient cause the ASAS to engage, and the difference in gains due to ASAS (gain of 6) in the working channel and the normal SAS in the monitor channel (gain of 4) caused the normal SAS channel to tripout.

During the flight RAS was engaged and the pilot pulsed the aircraft to obtain information on the RAS. The pilot noted that the RAS out light stayed on during the test and he was uncertain if the system functioned. Flight records indicate that the RAS did not function during the flight. The reason for the RAS not functioning is that the launch occurred with the RAS automatic cut off switch in the "on" position. When this switch is in the "on" position, the RAS is automatically cut off when the aircraft's normal acceleration exceeds a preset "g." The threshold "g" may have been exceeded during rotation before the pilot engaged the RAS for the RAS checkout. It is recommended for future flights that the automatic cutoff switch be in the "off" position at launch and engaged after engine burnout.

The automatic landing disengage switch was used for the first time on this aircraft. The servos were centered and locked at approximately .25 seconds after main gear touchdown. The maximum stabilizer deflection was -8° approximately .72 seconds before nose gear touchdown.

Wilton P. Lock