X-15 OPERATIONS FLIGHT REPORT

FLIGHT NO: 1-66-111 DATE OF REPORT: 8/17/66

PILOT: John B. McKay DATE OF FLIGHT: 8/11/66

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

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

PURPOSE OF FLIGHT: 1. Apollo Horizon Scanner

2. Wing Pods
(a) Micrometeorite
(b) Skybrightness
(c) Pace Transducer
(d) RH Pod Vibration
3. Electrical Loads

I. Discussion of Previous Operations

A. The electrical power transients of Flight 1-65-108 were duplicated on the flight of this report, 1-66-111, with marked exactness. Evidence indicated that the IFDS, MIT, and SAS are responding to the same voltage transients shown on the tape A f trace. One new piece of information is available for the l-66-111 flight, since the Skybrightness wing pod experiment 5-amp slow-blow fuse failed; the data traces for the experiment also show drastic change during the same period of transient voltage from 10 seconds before burnout, lasting for a 30 second period.

B. The "C" band radar failed for the two previous flights because of a blown fuse. Between-flight checks of the circuitry and the radar components failed to reveal the cause. Prior to this flight, a grounding of the "C" band radar switch with an adjacent switch was located; normal operation was obtained for this flight.

II. Configuration Changes A. An Edevco accelerometer was mounted in the center section of the RH wing-pod to monitor pod vibration. III. Preflight Events A. An ASAS system buzz of the RH horizontal occurred during the ASAS preflight. The buzz could be damped out with controls movement and was initiated by the transfer from normal SAS to the ASAS. Replacement of the follow-up pot corrected the malfunction.

B. A fit check of the PMR experiment was accomplished on 8/2/66. Both upper and lower elevators were installed, the flip-top lid was installed, and the experiment was manually extracted to verify the possibility of installation. Interferences noted included:

1. Contact between the experiment RH rear corner and the door hinge arm, to be corrected by chamfering the corner of the experiment.

2. Contact between the experiment extending pneumatic source bottle and actuator pneumatics lines, to be corrected by line relocation.

3. Contact between experiment mirror support post (forward LH side and the tie-angle for the forward door hinge pivot) to be corrected by redesign of the tie-angle.

4. Contact of the upper elevator post closeout cover and the lower elevator cutout, to be corrected by enlarging the cutout hole. The post also contacted the oscillograph drum mounted on the bottom of the lower elevator which can be cleared with a 45° 1/4 inch chamfer of the post container.

These items are considered to be of minor concern; overall fit of the experiment and installation of the elevator lid were acceptable.

C. The IFDS effort between Flight 1-65-108 and 1-66-111 is listed as follows:

1. The IFDS carried on Flight 1-65-108 was operated in the aircraft on 7/30/66 without malfunction and the flight data was unloaded from the computer memory.

2. The vertical velocity indicator, instrument digital converter, and the computer were removed for laboratory checks. No problems were noted during runs. The computer components which are related to the vertical velocity indication function were replaced.

3. Another IFDS computer, vertical velocity indicator, and computer were installed and operated in the aircraft on 8/5/66. A combined run with SAS, MIT was later completed without malfunction.

4. The IFDS computer memory was lost during a power transient on Flight l-A-109 with precision B-52 power at 13 minutes to launch.

5. The IFDS computer used on the previous flight (with new vertical velocity circuit cards) was installed on 8/9/66 after Flight l-A-109. The system was preflighted before servicing on the morning of 8/10/66.

6. IFDS operation was demonstrated with APU power transfer on Flight l-A-110 without malfunction.

7. The power system voltage transients were again experienced in Flight 1-66-111 with computer dump and loss of data accuracy. See item I, A.

D. The following parts were replaced during preflight:
1. ASAS follow-up pot.

2. One protective panel because of a sticky relay.

3. No. 1 AC bus voltage regulator (it was intended to replace the No. 2 bus regulator; however, markings were in error) in relation to the IFDS power problem.

4. Elevator lid seal was cut during the PMR experiment fit check.

E. Satisfactory APU runs were accomplished on 8/4/66. The No. 1 system BCS pitch-down rocket leaked slightly during the BCS leak check run and was accepted for flight. This valve leaked sufficiently in Flight l-A-109 to cause windshield fogging and was replaced.

F. The aircraft was mated to B-53 #003 on 8/8/66.

G. Flight l-A-109 was completed on 8/9/66 with J. B. McKay as pilot. The IFDS computer memory was lost during a B-52 precision power transient. The IFDS computer was replaced. Post-flight cleanup revealed a leak in the No. 2 APU tank bladder which was replaced. The pitch-yaw RAS valve was replaced because of inflight leakage. The manual BCS roll-valve was also replaced when malfunction occurred during the pitch-yaw valve checkout. This effort extended into the start of propellant service the following morning.

H. Flight l-A-110 was completed on 8/10/66 with J. B. McKay as pilot. Several delays were incurred with the IFDS preflight checkout. The flight was canceled at the initial outbound course because of launch lake helicopter malfunction. The IFDS was demonstrated with an APU start and a power transfer from B-52 precision power to the APU bus. A ball-nose problem was suspected; however, post-flight checkout did not show a problem and good operation was obtained during the Flight 1-66-111.

IV. Flight Events A. Events through launch were normal.

B. The electrical power system transients with corresponding tripout of SAS, and IFDS dump was again obtained as described in part I, A.

C. A flight dynamic-pressure level of 2050 psf was experienced during the reentry. No apparent fuselage or horizontal stabilizer distortions or distress were noted during a quick inspection following flight.

D. The aircraft swung sharply to the left after landing. The landing gear shock-strut service was suspected as a contributing cause; however, the horizontal stabilizers were held full nose-down with little roll input available for direction control. A 15-knot side component also was affecting aircraft rollout.

Approved by: Prepared by:

Perry V. Row Ronald S. Waite

X-15 Senior Project Engineer X-15 Project Engineer