X-15 OPERATIONS FLIGHT REPORT

FLIGHT NO: 1-65-108 DATE OF REPORT: 8/16/66

PILOT: John B. McKay DATE OF FLIGHT: 7/28/66

CARRIER AIRCRAFT: B-52 #008 LAUNCH LAKE: Delamar

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

PURPOSE OF FLIGHT: 1. Apollo Horizon Scanner

2. Electrical Loads
3. Wing Pods
(a) Window shade
(b) Skybrightness
(c) Pace Transducer

I. Discussion of Previous Operations

A. The nose-gear strut was bent directly aft on the landing of Flight 1-64-107. The deformation occurred with the gear fully extended and before gear compression took place. A complete metallurgical and dimensional investigation was accomplished by NAA at LAX. All hardness samples in the buckled area of the outer barrel and the deformed portion of the inner barrel were considered within acceptable limits. Dimensions indicated a maximum clearance condition between relative barrel diameters reducing the possibility of binding. Stress calculations indicated the gear is capable of withstanding the drag loads of a non-rotating wheel, eliminating a tight bearing condition as a cause. Conditions at touchdown of Flight 1-64-107 lie in the middle band of present landing experience. Gear pneumatic servicing is accomplished on the day of flight and is related to gear strut extension time and load stroke characteristics which take place during and after strut compression. The pilot felt that the nose-gear touchdown load was normal. In short, the cause for the gear deformation has not been determined at this time.

B. The IFDS ground and airborne environment to date has been approaching the upper limits of the Autonetics D9A computer. Exact temperature readout has not been available because of inconsistent results from the PDM monitored parameters. Several steps have been taken to produce lower computer temperatures including decreasing the effects of the computer blower recirculation cover by opening holes at the intake blower. Although no problems have been attributed directly to the high temperature, an effort will be made to produce a 65°F temperature level by adjusting the air-conditioning duct configuration.

II. Configuration Changes A. The IFDS computer dump signal provided by both alternator-control relays in case of alternator loss was deactivated to reduce the sources of possible IFDS computer dump (a 28V DC signal at pin little p of the computer disconnect).

B. The altitude predictor was eliminated as a source of IFDS analog input loading because of unknown system interface effects. This was accomplished prior to Flight 1-64-107.

C. The No. 1 BCS system chamber pressures were restored to the instrumentation configuration. The tape recorder was reconverted to the MIT Phase II parameters. Both changes eliminated the IFDS electrical power monitoring configurations of Flight 1-64-107.

D. The wing-pod experiments installed included:

1. Micrometeorite collector

2. Nortronics Skybrightness scanner

3. The RH pod including the pace transducer remained unchanged from the previous flight

E. The RAS case was removed for use in X-15-2.

F. A plug which had been installed in an air-conditioning duct in the past to avoid over-cooling the IFDS computer was removed to improve the IFDS temperature environment.

G. The MIT Phase II experiment and tail-cone replaced the lightweight tail-cone assembly.

III. Preflight Events A. Aircraft functionals resulted in replacement of components:
1. No. 1 APU controller

2. D.C. power supply for the MIT Phase II experiment

3. Complete nose-gear assembly (see item I, A). The "bent gear" was installed after the Delamar landing. This gear was refurbished with new outer and inner barrels after the Cuddeback landing of X-15-3 which resulted in a bent gear. Testing at Loud included drop testing of the new parts with subsequent disassembly and inspection. Flight 1-64-107 was the first landing after repair of the nose strut. The replacement gear was the gear which was removed after the Delamar landing for precautionary inspection; this gear had been sent to LAX, cleaned, inspected, and returned to X-15 stock.

B. Satisfactory APU runs and BCS leak checks were accomplished on 7/15/66.

C. The aircraft was ready for mating on 7/21/66; however, scheduling difficulties prevented a flight attempt until Monday, 7/25/66. The aircraft was mated to B-52 #008 on 7/22/66.

D. The aircraft servicing was completed on 7/25/66; however, range weather was marginal. The IFDS computer program timing was incorrect accompanied by a maximum gyro torque rate requiring flight cancellation.

E. The flight was rescheduled for Thursday, 7/28/66. Several problems were evident during IFDS functional checks. A replacement computer was installed after two changes of a rectifier circuit board. A second IFDS computer was installed, and after correction of a GSE data loader, a normal run was accomplished.

F. An engine electro-mechanical preflight was completed on 7/27/66.

IV. Flight Events A. A precise takeoff time and outbound schedule was made to simulate PMR launch procedure. The attempt was successful, producing a near perfect launch timing.

B. An extended elevator bay precool using the air-conditioning with an increased pressure of 3.0 psig resulted in IFDS temperature of 65° to 68°F.

C. The IFDS rate-of-climb indicator malfunctioned after the power transfer at 8 minutes to launch. The system operation was demonstrated by selecting the altitude undamped mode, and the decision was made to launch without the rate-of-climb function.

D. The "C" band radar failed at three minutes to launch because of a blown circuit breaker.

E. Transients on the No. 2 alternator A.C. bus during a 30 second period starting approximately 10 seconds before burnout resulted in an extended IFDS computer dump, trip-out of pitch-roll SAS, and transients in the MIT system. The IFDS was reset after the transient period; however, considerable error was built up as a result of the data loss. SAS reverted to ASAS operation and was eventually reset without further problems.

F. The MIT photometer signal wire was found broken after flight resulting in some loss of data.

G. The Micrometeorite experiment cycled during flight with normal opening and closing operations; however, a T.C. wire looped over a sprocket permitting exposure of only two of the six faces.

Approved by: Prepared by:

Perry V. Row Ronald S. Waite

X-15 Senior Project Engineer X-15 Project Engineer