Flight 3-55-82 was flown on September 14, 1966, by William H. Dana for the purpose of pilot familiarization and to obtain data for: a) cockpit display evaluation, b) solar spectrum measurement experiment, c) dual channel radiometer, d) micrometerorite collection, e) pace transducer, and f) tip pod accelerometer.

Data were scheduled to be obtained for boundary layer noise and for checkout of the Alert computer of the energy management system and heat transfer panels.

The maximum velocity attained was 5250 fps (3580 mph) and a Mach number of 4.96 at an altitude of 140,000 feet. The maximum altitude reached during the flight was 252,000 feet.

This flight was the fifth flight of Mr. Dana's, completing the series for pilot checkout in the X-15. The flight was flown essentially as planned. The third skid did not extend during landing due to a malfunction of the activating system. The pilot reported a high frequency noise was present during radio communications. An engine alignment was recommended to correct a 3 degree angle of sideslip reported at shutdown.

Data were obtained as planned with the following exceptions: a) data were partially obtained on the dual channel radiometer and the equipment returned to experimenter because of malfunction of the Milikan camera, loss of calibration signal and possible loss of one channel of data; b) data were obtained on the solar spectrum experiment, however, the filters were coated with an oil film and noise on the data channel may invalidate the data. An analysis of the film is to be conducted by the experimenter; c) the micrometerorite equipment malfunctioned during preflight and was returned to the contractor for repair; d) the energy management system was not functioning properly in the service area and was not activated during the flight; and, e) one microphone of the BLN did not function properly during the flight.

Profile

Launch was normal with the engine light occurring 1.0 seconds later. The engine reached maximum thrust in approximately 2 seconds. The airplane initially was rotated to 15° angle of attack and then settled down to average approximately 10°. Peak AN during the rotation was approximately 2.4 g.

The planned 38° pitch attitude was attained at 33.6 (planned 28 seconds) seconds and was held to shutdown which occurred at approximately 79 seconds as compared to the expected 77 seconds. The pilot noticed about 3° of nose right sideslip prior to shutdown and corrected it with rudder. The angle of sideslip indicates an engine thrust misalignment during the boost phase. Shutdown velocity was the planned 5150 fps with tail off to about 5250 fps.

The pilot switched to a/b mode and pushed over to zero degrees angle of attack as planned. The pushover required more time than the simulator indicated. The roll maneuvers requested for the dual channel radiometer were not performed. The computed angle of attack light started flashing at about 190,000 feet, however, the pilot elected to use the ball nose data until the predicted switch point of 220,000 feet. Computed b was about 4 degrees in error and a was considered satisfactory. The roll mode was engaged at this time.

The aircraft reached a peak altitude of 252,000 feet as compared to the planned 250K. The pitch attitude hold was engaged at peak altitude. Telemetry was lost for approximately 40 seconds over the top. The cockpit film indicated that pitch and roll attitude held within the prescribed ±2° limits.

The hold modes were turned off at 220K on the way down and the pilot went back to ball nose a/b. Reentry angle of attack originally rose to 25 degrees but settled down to the planned 20 degrees. This was held until the pilot reached and maintained approximately 4 g during the entry. Maximum g on reentry was 4.5. The remainder of the flight was flown as planned.

Dual Channel Radiometer

The Milikan camera which was required for the experiment malfunctioned. The camera is believed to have frozen up due to a faulty tail cone box heater. The pilot did not perform the roll maneuver which the experiment required. The data have been reviewed and it appears that only one channel functioned properly. The data and equipment are being forwarded to the experimenter for further analysis.

Solar Spectrum Measurement

A preliminary review of the data shows excessive electrical noise on the data channel. The other two channels functioned properly. The experimenter does not consider the data to be of sufficient quality to be considered valid. The experiment will be analyzed to isolate the source of the noise and filters will be devised to eliminate these noise problems. Following the flight the experiment was examined and an oil film was observed as a coating covering the experiment filters. An analysis of the film will be made to determine the source. The covering of film also would invalidate the data due to the accuracy requirements.

Pace Transducer

Data were obtained on this experiment. However, at this time the data have not been closely examined to see it they are usable.

Tip Pod Accelerometer

The data have undergone a preliminary analysis. The data have not been subject to vibrational analysis, however, the preliminary analysis did not reveal divergent vibrations. Data obtained from the flight are expected to be subjected to vibration analysis during the week of September 18.

Cockpit Display

There was only one discrepancy noted in the Lear panel during the flight. The "g" meter oscillated severely at launch. This problem is now being examined.

Micrometerorite Collection

The micrometerorite collection experiment was not available for this flight. The experiment did not function properly during preflight activities and was removed from the aircraft. Attempts to perform functional bench checks of the equipment were not successful and the experiment was returned to the contractor for repair. The experiment is expected to be available for the next flight of X-15-3.

Boundary Layer Noise

Three microphones were flown during this flight to obtain data for BLN. The microphones were of 1/2, 1/4, and 3/16 inch diameter and were flown to obtain data to evaluate the effect of microphone size on BLN data. Data were obtained on the 1/2 and 1/4 inch microphones, however, the 3/16 inch microphone did not appear to have functioned properly. Analysis of the data is being conducted to determine the source of the malfunction.

Energy Management System

The Alert computer was installed for checkout during this flight. Attempts to operate the system in the service area before the flight were not successful. The computer was run in the lab and functioned normally in the warmer environment. The computer is located in front of the cooling duct outlets in the instrument bay. To correct this the cooling air will be rerouted, and it is believed that this will alleviate the problem.

Instrumentation Discrepancies

0-21-36C - There was only one calibrate trace on channels 14 (roll BCS) and 27 (yaw BCS).

0-23-36C - There was excessive noise on channel 30 on the JPL data channel.

0-7-36C - Channel 35 (the main gear uplock hook strain gage) has an off scale calibrate.

P-101-2 - The traces shifted on cells G-163 and G-264.

Operational Discrepancies

The Energy Management System computer froze up before B-52 takeoff and no qP/qL readings were displayed.

The third skid failed due to a burnt connector which powered the squibs. The plug has been replaced and insulated.

The pilot stated that there was a high pitch sound in his radio possibly 400 cycle/seconds. This problem is presently being examined.

The pilot recommended an engine alignment to correct the 3 degree angle of sideslip to the right at 100K during the boost portion of the flight. The pilot tried to correct by a rudder input, but it did not correct the condition. The engine has been moved 1/4 inch to the right to correct for this thrust misalignment.
 

(James R. Welsh) for

E. J. Adkins, Chief

X-15 Research Project Office