X-15 OPERATIONS FLIGHT REPORT



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 Loads

3. Third Skid Checkout

4. Stabilizer Ablatives

5. Sonic Boom Study

6. Precision Attitude Indicator Checkout


I. Discussion of Previous Operations

A. As indicated in the last flight report (for Flight 1-69-116) a rupture was found in the forward bulkhead of the NH3 tank which allowed out-of-sequence transfer of fuel and eventually a massive ingestion of helium gas in the feed line to the engine, causing a premature shutdown.

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.

 II. Configuration Changes A. Due to the long "down time" required to repair the damaged fuel tank, and the onset of the winter weather, it was decided to undertake an extensive updating program. A large number of EO's and NASA sketches were incorporated and a detail listing of these is given in Appendix "A" attached.

An abbreviated summary of the major items added to the X-15 is listed below:
 

1. Modification for increased main landing gear deployment loads including honeycomb snubber for main landing gear skid.

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.

 III. Preflight Events A. Following completion of the fuel tank bulkhead repair at NAA, LAD, the aircraft was delivered to NASA by truck on February 3, 1967. Component reinstallation, and general rerigging was begun. A preliminary fit check of the PMR experiment was made on February 14. Several minor interferences were noted and modifications were devised to obtain acceptable clearances.

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.

 IV. Flight Events A. The flight objectives were accomplished although two major in-flight failures occurred:
  1. The inertial system failed at or near peak altitude.

2. Cabin pressure system failed at approximately the same time.
 

 B. Post flight inspection showed a broken electrical connection between the auxiliary cabin pressure switch and the LN2 solenoid valve. Thus the required LN2 was not supplied and cabin pressure was not maintained.

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.
 

 Approved by: Prepared by:

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

A. ECPNA-X-15-210 Increased deployment airloads on main landing gear (honeycomb snubber).

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)

 
1. Aircraft wiring per 240-75261 (W/0-4128, 4757, and 4760).

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.

 
1. Move "Q" indicator to 3" altimeter position.

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

 
1. New LH console constructed to install control-head.

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.

 II. Aircraft Configuration Changes A. A series parallel wiring scheme for the nose BCS heaters per SK-2057, W/0-4128.

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.

 III. Instrumentation Configuration Change A. Motor/Generator (M/G) power supply for the Verdan computer; in-flight operational test, dissipating output with resistive load.  
1. Load-bank resistor per EC-0-550, W/0-4800.

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.

 B. Add an MIT fuse box per EDI-853, vies 670-437A, W/0-4764.

C. IRIG time code generator and control switching (location on LH console forward of M/G location).

D. Removal of unused systems including:

1. VDR-4 camera.

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.

 E. Relocation of the radio antenna from C.G. bay to position forward of Sta. 200.

F. Removal of T.C. oven allowing relocation of 12 channel thermistor box and MIT isolation amp brackets per SK-2113, W/O-4797.

 IV. Maintenance Items A. Replaced the engine H2O2 tank requiring transfer of mounting holes to mounting ring. Rework was required at NAA to raise the tank to eliminate interferences.

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).