X-15 OPERATIONS FLIGHT REPORT

FLIGHT NO: 1-67-112 DATE OF REPORT: 8/26/66

PILOT: John B. McKay DATE OF FLIGHT: 8/25/66

CARRIER AIRCRAFT: B-52 #003 LAUNCH LAKE: Delamar

ENGINE SERIAL: 107 APU #1 16AN APU #2 20AN

PURPOSE OF FLIGHT: 1. MIT Apollo Horizon Scanner

2. Wing Pod Experiments
(a) Micrometeorite Collector
(b) Pace Transducer
(c) Wing Pod Vibration -
Configuration with symmetrical
Pod weight
3. Electrical Loads

I. Discussion of Previous Operations

A. The inflight No. 2 alternator bus voltage transients are attributed to altitude-temperature effects on the Nortronics Skybrightness experiment installed in the RH wing pod rear cone. The inflight electrical load transients were reproduced in the FRC environmental laboratory. A brief discussion of the test is outlined in paragraph III, H. Removal of the experiment for this flight eliminated the large electrical load transients which caused dropout of SAS and IFDS computer dumps.

B. The confidence level for the "improved" RAS case has not increased with recent operational experience. One of the two existing improved RAS cases exhibited the characteristic, intermittent rocket operation without the proper rate command. Although the malfunction disappeared in laboratory operation, the case was not considered acceptable for flight use. A replacement case arrived from NAA -LAX, and was installed for flight. Acceptable operation was obtained in flight.

II. Configuration Changes A. The Nortronic Skybrightness Experiment was not installed for this flight. A spare tail cone with ballast was installed. III. Preflight Events A. Engine S/N 107 was qualified for flight without a ground run based on data evaluation and post flight inspections. This flight was the fourth in a series of inflight operation without ground run. The last engine ground run was accomplished on S/N 107 on 5/31/66.

B. The following components were replaced between flights:

1. The No. 2 APU alternator was replaced as part of the corrective action on the inflight voltage transients.

2. The No. 2 APU voltage regulator was changed for reason of (1) above.

3. The No. 1 APU catalyst bed was changed for time compliance.

4. The SAS RH servo-actuator and SAS Electronics case servo-amplifier module were replaced to correct an oscillation of the RH horizontal surface which occurred during preflight activities. The roll channel notch-filter module and the roll output working-channel amplifier modules were also changed during the trouble-shooting but were not related to the malfunction.

5. The RAS electronics case was replaced because of intermittent right yaw rocket operation. The case was checked in the laboratory where the malfunction repeated once but then could not be repeated in subsequent operation (typical in the history of this system).

C. Time-compliance inspection items accomplished included:
1. BCS roll tension-regulator travel.

2. Visual inspection of the interior of the engine H202 tank.

D. The No. 2 APU was removed from the aircraft to accomplish the replacement of the alternator and to trouble-shoot the electrical current load transducers.

E. The canopy mechanisms were adjusted to reduce the canopy opening and closing handle loads. Readjustment produced the desired results.

F. A close inspection of the aircraft structure was accomplished as a result of the high dynamic-pressure experienced during the previous flight (2050 psf approximately). As well as visual inspection and human memory can be relied upon, no significant structural changes were noted.

G. The IFDS component configuration was retained from the last flight. As part of the temperature environment problem, an air-conditioning duct which was previously removed for better air distribution was reinstalled to direct more -40°F air into the area of the IFDS computer.

H. An environmental test was conducted on the Nortronics Skybrightness to demonstrate the cause for the blown fuse on the previous flight.

1. The experiment was mounted radially on a centrifuge and tested to a "G" range of 3.5 to 6.5 depending on radial position. No electrical current load fluctuations were produced.

2. An altitude-temperature combination test was completed which produced current spikes and notable degradation in photometer signals.

a. A temperature cycle from ambient to -70°F produced no results.

b. An altitude cycle at -70°F produced a data degradation period at 110K altitude and a (2) amp slow-blow fuse failure at 140K altitude.

c. An altitude cycle at -40°F did not produce a current failure on the increase portion to 160K, however, fuse failure occurred at 140K on the decreasing altitude portion.

I. An acceptable APU run was accomplished on 8/23/66. A demonstration test including SAS, IFDS, and MIT operation was made with the total electrical load supplied by the No. 2 alternator to evaluate interface effects. The systems were not affected by simultaneous operation.

J. Engine preflight functionals were accomplished on 8/24/66.

IV. Flight Events A. Aircraft propellant service and captive flight were uneventful.

B. PDM was lost completely at launch. Recovery was made for a short time in the landing pattern, however, the PDM transmitter output was very low.

C. The IFDS performance was good for the first 300 seconds after launch. A computer program malfunction occurred at 80K during reentry, degrading the system cockpit displays for the remaining portion of the flight.

D. No X-15 electrical bus voltage spikes were experienced during the flight which previously affected SAS, MIT, and IFDS.

E. A post landing-weight measurement was accomplished at 14,565 pounds.

Approved by: Prepared by:

Perry V. Row Ronald S. Waite

X-15 Senior Project Engineer X-15 Project Engineer