July 21, 1966

MEMORANDUM for Chief, Research Projects Office

Subject: Preliminary report of X-15 flight 1-64-107.

Summary

Flight 1-64-107 was flown by Major W.J. Knight on July l2, 1966, for the purpose of (a) pilot familiarization, (b) electrical loads evaluation, (c) non-glare glass evaluation, (d) stick kicker evaluation, (e) window shade evaluation, and (f) inertial system power survey and analysis.

The flight was flown essentially as planned, although the maximum velocity appears to be about 300 FPS higher than planned. The stability maneuvers were accomplished as planned.

Data were not obtained on the three phase power supplied by the APU's, as recorded internally. The tape recording has not been analyzed to determine whether data were obtained on the APU electrical loads measurements.

The face plate of the alpha indicator instrument was of non-glare material during this flight. The pilot did not comment on the effects of using non-glare glass nor did he indicate glare to be a problem during the flight.

The inertial system functioned normally during the flight and data were obtained for analysis.

The stick kicker functioned normally although the pilot indicated he was unaware of actuation of the kicker. The pilot also pushed over at main gear touchdown.

Flight Profile

The main purpose of the flight was to familiarize the pilot with the aircraft handling qualities at high angles of attack with the SAS disengaged. This was Major Knight's third checkout flight and his first flight at 100% thrust .

The flight profile was flown essentially as planned as shown in figure 1 although the maximum velocity was approximately 300 FPS higher than planned.

The launch appeared normal with only 20 degrees of right roll off. The angle of attack was about 8 degrees at engine light and was increased to 13 degrees. During the remainder of the roundout after an initial droop to 7° angle of attack, the pilot maintained a constant 10 to 11 degrees angle of attack. The maximum normal acceleration was about 2.4 "g". The desired 30 degrees of pitch attitude was attained at 24 seconds. The pilot reported he felt that he was continuing to rotate while holding pitch attitude constant at 30 degrees, but convinced himself to believe the indicated attitude.

Planned shutdown was to have occurred at 5300 FPS after 80 seconds of engine burn time. After missing the throttle on his first attempt the pilot shutdown and reported that the maximum velocity he saw was 5400 FPS. Preliminary radar data indicated that the shutdown occurred at 5600 FPS and 95,000 feet. A total burn time of 83 seconds was determined from longitudinal accelerations.

After shutdown, the angle of attack was increased to the planned 15 degrees and the dampers off stability maneuvers were performed. After disarming the ASAS, the pilot performed a rudder pulse with the yaw damper set at low gain and repeated the pulse with the yaw damper off. The roll damper was then disengaged and the pilot evaluated the controllability while maintaining 14 to 17 degrees angle of attack. The pilot felt that the controllability was very good and better than the simulator. The pilot commented on a 2 degree b offset during this time period and the small b oscillation that did exist was about this offset point. Data records indicate that this b offset occurred as the angle of attack was increased from 10 to 15 degrees and returned to zero upon decreasing angle of attack from 15 to 10 degrees. The speed brakes were extended to approximately 25 degrees at peak altitude and the controllability evaluation with the roll and yaw dampers off was continued. During the descent the roll and yaw dampers were reengaged. The pilot disengaged the pitch damper and a pitch pulse was performed.

During a vectoring turn above Mach 3 at approximately 9 degrees angle of attack the pilot reported a buffet and pushed over to decrease the angle of attack. Internal records were checked to identify the source of the buffet and at the present time flow separation around the speed brake is suspect.

The approach to high key was normal. During the pattern the pilot extended partial speed brakes because he was slightly higher than desired. The brakes were not retracted prior to landing and the aircraft touched down short of the two mile marker.

Electrical Loads

Data were not obtained for the survey of the electrical loads on the APU's. The number 1 APU three phase power instrumentation did not function properly.

Non-Glare Glass

Non-glare glass was installed as the face plate of the alpha indicator. The pilot did not report glare to be a problem in the cockpit during the flight and did not comment on the effects of using non-glare glass as instrument face plates.

Stick Kicker

A service pressure of 800 PSI was utilized in the stick kicker system for this flight. The pilot reported he was not aware of system operation and pushed over at main gear touchdown. Internal recordings indicate the pitch horizontal stabilizer deflection was about -3 degrees at main gear touchdown. About 1.1 seconds after main gear touchdown the stabilizers had been driven to a +7 degrees position.

Inertial System Evaluation

The inertial system functioned normally during flight. All data requested were not obtained. Analysis of that data recorded on the tape recorder is continuing for system evaluation.

Instrumentation Discrepancies

The pitch, roll, and yaw AVAAT's did not function properly during the flight.

The alpha recording indicated a 12 cps oscillation during the flight. Analysis of this problem is continuing.

At a callout from NASA 1, data were turned off during the flight and resumed just prior to touchdown. This was required to record touchdown after about 9 minutes of film time were used to record the inertial system operation during prelaunch.

The following parameters did not record during the flight:

APU #l power A phase

APU #1 power B phase

APU #1 power C phase

Calibrations were not obtained for:

Angle of attack and sideslip

Upper vertical stabilizer

Roll horizontal stabilizer

Console stick lateral force

Longitudinal trim position

SAS yaw cylinder displacement

Main chamber pressure trace was erratic and intermittent during the flight.
 
 
 
 

E. J. Adkins, Chief

X-15 Research Project Office