Flight 3-53-79 was flown on August 4, 1966, by William H. Dana for the purpose of pilot familiarization and to obtain data for a) heat transfer experiment, b) Lear cockpit display evaluation, c) horizontal stabilizer loads, d) boundary layer noise measurement, e) optical background experiment (#25).

The maximum velocity attained was 5400 fps (3682 mph) and a Mach number of 5.4 at an altitude of 98,000 feet. The maximum altitude reached during the flight was 131,000 feet.

This flight was Mr. Dana's third flight in the X-15 and it was accomplished essentially as planned. There were no major malfunctions during the flight and some acceptable data were obtained on all experiments.

Flight Track and Profile

The radar flight track and altitude profile for flight 3-53-79 are shown in figure 1. A time history of the flight is shown in figure 2. On the time history, the altitude and velocity are adjusted raw radar data. The other parameters are telemetered data.

A normal launch was made from Mud Lake #2 (West) on a heading of about 170°. A turn to the planned track heading (172°) was made immediately after launch and the flight track subsequently paralleled the planned track. Initial rotation after engine light was at about 15° angle of attack (figure 2), followed by a nearly constant 9° angle of attack as the rotation continued to a pitch attitude of about 30°. The pushover to zero normal acceleration occurred nearly on schedule, but the engine shutdown was one second early. The shutdown conditions were 5400 fps at an altitude of 98,000 feet (planned values were 5300 fps at 95,000 feet). The maximum altitude reached 131,000 feet, was 1000 feet higher than planned.

After engine shutdown, the pilot performed stability and control pulses with dampers on and off to evaluate the airplane handling qualities. Also, a series of push-pull maneuvers were performed for boundary layer noise and horizontal stabilizer loads data.

The entry was made at an angle of attack of about 10° as planned with speed brakes extended 20°. The approach and landing were accomplished without incident. Data were obtained during the landing to evaluate the operation of the stick kicker and third landing gear skid. The pilot felt the kicker for the first time and did not find it objectionable. Its operation was satisfactory.

Stability and Control

The stability and control evaluation performed on this flight was primarily for pilot familiarization. This was the third flight in the X-15 for the pilot.

Rudder pulses and rolling maneuvers were performed with damper on full adaptive, fixed gain and off to evaluate handling qualities at 15° angle of attack and at a Mach number of about 4.5.

Horizontal stabilizer pulses were performed with the damper off at an angle of attack of 10° and a Mach number of about 4 to evaluate the longitudinal handling qualities.

With the dampers off the pilot rated the controllability at 4.5 in pitch, 3.5 in roll and 3.0 in yaw. The pilot also stated that the aircraft flew better than the simulator with the dampers off.

No unusual characteristics or occurrences were noted during the flight.

Cockpit Display

This was the second flight for the Lear vertical tape instrument display panel. The only observed discrepancy in the Lear panel was in the tape q reading which continuously read 50 psf higher than the q-meter. The gauge was calibrated with a mercury column before the flight. The instrument will be calibrated again along with the q-meter and it is believed that this will alleviate the problem.

The pilot felt the cross check in the aircraft was not as good as in the simulator. He also said that h and h meters were most frequently used during the boost phase.

Other than the q discrepancy the pilot said he was "satisfied" with the panel.

Heat Transfer

Newly instrumented heat transfer test panels were installed near the lower fuselage centerline. On the flight the thermocouple and recording system was to be functionally evaluated.

After a postflight check of the thermocouples it was noted that only one thermocouple malfunctioned, this was TC 09059. The preliminary data have been reviewed and are now undergoing a closer check to determine if it can be used for analytical purposes.

Research heat transfer data will be obtained on subsequent high speed flights at high dynamic pressure.

Horizontal Stabilizer Loads

Five abrupt pull-ups and/or push-pull maneuvers were accomplished to obtain loads data on the horizontal stabilizer. The maneuvers were made at Mach numbers of about 5.2, 4.3, 3.6, 2.8, and 1.3 at moderate dynamic pressure.

After a postflight checkout it was noted that all the strain gauges were operable except for the right hand #4 gauge (ch. 12).

Optical Background

Data were obtained for this experiment. There has been a preliminary review of the data and it now appears that only one channel out of two has data. At this time the data have been forwarded to NSL and are undergoing further analysis.

Instrumentation Discrepancies

The galvanometer on O-23-36C which recorded the computer internal thermistor was under damped.

Channel 19 on 0-23-36C (800 E, V, throttle micro switch) shifts at landing for approximately 2.5 seconds.

Approximately 24 feet of film was blank on 0-21-36C because the magazine was not secured to the oscillograph. Film appears to have slacked at engine start also. There was not sample switch pulse on O-21-36C (ch. 1) due to a malfunction in the hold circuit. Channel 35 (tail cone camera timing) did not operate because the camera did not function. In both roll and yaw BCS channels (14 and 27 on 0-21-36C) there is a calibration trace missing.

Channel 33 on 0-21-36C (inertial altitude) changed twice very rapidly and the reason is not apparent.

The airspeed film P-2-4E was ruined during processing.
 

Elmor J. Adkins, Head

X-15 Research Project Office