FLIGHT NO: 1-70-119 DATE OF REPORT: 3/27/67
PILOT: Maj. Mike Adams DATE OF FLIGHT: 3/22/67
CARRIER AIRCRAFT: B-52 #003 LAUNCH LAKE: Mud #2
ENGINE SERIAL: 108 APU #1 16AN APU #2 20AN
PURPOSE OF FLIGHT: 1. Pilot Buildup
2. Electrical Loads3. Third Skid Checkout
4. Stabilizer Ablatives
5. Sonic Boom Study
6. Precision Attitude Indicator Checkout
I. Discussion of Previous Operations
Analysis and subsequent tests, using the Propulsion System Test Stand, has shown that a pressure surge beyond the design limit of the bulkhead can be reached during the rapid opening of the jettison valve. An orifice has been added to the control gas inlet of the jettison valve to slow its operating time and reduce this surge to an acceptable level. This design change is effective for all three X-15 aircraft.
NAA submitted ECP #245 for repair of the ruptured bulkhead and on December 5, 1966, the X-15 was delivered by truck to Los Angeles Division. During the period of this repair, a number of other design changes were incorporated (see Item II below).
B. The nose gear strut was found to have been bent following Flight 1-64-107 and again following Flight 1-69-116. A discussion of the item is found in III-C of this report.
An abbreviated summary of the major items added to the
X-15 is listed below:
2. Third skid system.
3. PMR UV tracking experiment.
4. "Flip Top" lid made operational.
5. Yaw ASAS.
6. ARC-51 radio.
7. Precision Attitude Indicating system.
8. Motor generator for inertial computer and load bank for testing the generator.
B. On February 28, a combined functional test was run with the PMR and MIT systems and the inertial system operating. Minor squawks were noted and corrective action taken during the following days.
C. On March 3, the nose gear strut was found to be binding up, when attempts were made to rotate or compress it during preflight checks. The gear was removed and sent to NAA for detail inspection. It was found that the strut was bent, in a similar manner to the incident reported for Flight 1-64-107. No positive cause for that incident had ever been determined, and landing loads for both that incident and this new occurrence were well within limits.
Since X-15-3 has not experienced any nose gear deformation of this type a comparison of the two aircraft was made. One major difference was noted: X-15-3 has been using up the remaining 10 ply tires while X-15-1 has been using the newer 12 ply high pressure tires. It is presently thought that the 12 ply tires which have a slightly greater weight and inertia than the 10 ply may be inducing excessively high drag loads during spin-up. Accordingly, pending further study X-15-1 and X-15-3 will use only 10 ply tires, and preferably mounted on magnesium wheels, instead of the 12 ply tires and high pressure aluminum wheels.
D. A cabin leak check was performed on March 7. Leakage rate was 94 CFM. It was decided to reseal the areas which showed high leakage. A recheck on March 9 gave 86 CFM and it was decided to accept this leak rate.
E. Preflight functionals were generally normal. Engine and APU/BCS ground runs were made on March 6. During the first pump idle run the governor failed to pick the pump RPM above "slot" speed. Subsequent pump runs and all hot firings of the engine were normal, and it was decided to accept the engine for flight.
F. The flight was scheduled for March 13 but heavy weather forced cancellation. The C-130 support aircraft was not available on March 14 and the flight was again canceled.
G. Marginal weather forced an abort (l-A-117) after B-52 takeoff on March 15. Poor radio communications necessitated some rapid trouble shooting that evening. The ARC-51 radio was replaced and repairs made to the electrical Q/D on the pilots seat.
H. The flight was canceled Thursday, March 16 for heavy weather and it was decided to demate to permit compliance with a B-52 phase inspection over the approaching weekend. The X-15 was mated again on Monday, March 20.
I. Another abort (l-A-118) was logged on Tuesday, March 21, when the inertial system failed during captive flight. The inertial "J" box was replaced that evening.
J. The flight was finally completed on Wednesday, March 22, 1967.
2. Cabin pressure system failed at approximately the same
time.
C. All recent inertial failures, including that reported during the flight, seem to exhibit the same general symptom, that of an AC power failure. An extensive continuity check, and inspection of all components relating to distribution of AC power within the inertial system has been undertaken. Final results are not available at this writing.
D. Inspection of the "honeycomb" crushable inserts in
the main skid snubbers showed them to be crushed excessively. X-15 air
speed at gear deployment was well within limits. Close examination of the
honeycomb inserts revealed them to be incorrectly fabricated and their
density to be approximately 1/2 of the required density. Corrective action
is to be taken by the contractor (NAA) to assure 100% inspection of all
honeycomb inserts. Present inventory of inserts has been inspected and
all incorrectly fabricated inserts removed from stock.
Perry V. Row William P. Albrecht
X-15 Senior Project Engineer X-15 Project Engineer
APPENDIX "A" TO FLIGHT REPORT 1-70-119
I. Major Modifications
EO-00052 900582 901904 902404
54 583 918 408
900578 901902 902402 457
579 903 403 461
581
B. ECPNA-X-15-212 Third skid system
EO-00051
55
900125 Wiring, also consult NASA SK-2002 and X-15-3 for general routing per W/O-4128.
126 900569 901922 902905
127 587 925 922
539 591 902401 924
554 596 407 937
555 901901 414 939
558 910 903 948
568 921 904
C. Ultraviolet, Infrared Tracking System (PMR)
2. FRL shelf harness cutout per EO-898948, W/0-4127 and modified by W/0-4752, SK-2066.
3. Center pedestal control panel P/N 2581-75303-3 with door source gage P/N 1037-1-A, W/0-4126; canopy control panel 240-75261.
4. Provide structural clearance for upper elevator extension housing, W/0-4770 per SK-2079.
5. Relocation of door actuator line support bracket per IFS item.
6. Data compatibility with MIT and PMR systems, W/O-4756 (affects engine vibration also).
7. Flip-Top lid assembly completed including experiment sequence valve.
D. Yaw ASAS
Control panel wiring per SK-2019, W/0-4131. Buildup of SAS-ASAS-RAS control panel per EC-0-525, Sheet l & 2, W/0-4741. Affected EO's:
00361 901327 336
00377 328 902855
901326 334 863
Modification of the GSE per 902855 of E-9099-21 accomplished and a new harness E-9247 was supplied.
E. Pilots control panel changes to accommodate Precision Altitude Indicator, W/0-4130.
Eliminate 3" inch altimeter.
Add 2" altimeter.
Add pitch-roll set control-head to pilots panel.
Add switch to control MIT vector and precision altitude.
2. Mount Amp/Demod box.
3. Configuration per 670-I-4121-1 for precision altitude and 670-I-4735 for MIT vector. ECI-1093B (W/0-4753) provides IFDS outputs from ECU to Amp/Demod box; Vector display per EDI-853.
F. ARC-51 Radio, W/0-4129
2. Old radio and power-supply tray removed to allow revised mounting.
3. Added space allowed installation location for Hadley transformers, Digital timer, ASAS Yaw electronic case, and radio coaxial filter.
B. APU bearing temperature indicator and dualized switch in the pilots panel, SK-2003, W/0-4128.
C. Addition of a check valve in the accumulator return line per EO-899842, Drawing 240-58004 "F", W/O-4794.
D. Installation of a flow limiting orifice in the fuel jettison valve control to slow valve opening per EO-01481, 899842, 00097 (W/O-4794). Use of 240-48317D, 240-48167B Spacer, 240-48545B Orifice, part of 240-48317-11 Assembly.
2. Power C/B placards, W/0-4718, SK-2050.
3. Wiring EDI-871B.
4. M/G cooling plate EC-0-542.
5. M/G mounting on modified LH rear console EC-0-544.
6. LN2 cooling valve bracket, SK-2114, W/O-4797.
7. Resistor attach clips, SK-2130, W/0-4804.
C. IRIG time code generator and control switching (location on LH console forward of M/G location).
D. Removal of unused systems including:
Heat sound and gas hog
IR Scanner wiring
Per W/O-4762 and EDI-603F, 525
2. Strain gage commutator signal and power wiring, EDI-797A.
F. Removal of T.C. oven allowing relocation of 12 channel thermistor box and MIT isolation amp brackets per SK-2113, W/O-4797.
B. Replacement of nose-gear door to improve mold-line fit (door previously fit and used on X-15-1, removed to comply with scoop-door hook change). New door brackets fitted to install door.
C. New SAS case P/N 662R615G01, Drawings 240-75240, 51701, per E0-0037.
D. New helium lines for the No. 2 APU source to correct leakage.
E. Replacement of the No. 1 APU shutoff valve because of tank pressurization in the "OFF" condition.
F. A revised NH3 vent valve.
G. Replacement of NH3 safety valve (load to X-15-3).