X-15 OPERATIONS FLIGHT REPORT



FLIGHT NO: 2-32-55 DATE OF REPORT: June 29, 1964

PILOT: L/C Rushworth DATE OF FLIGHT: June 25, 1964

CARRIER AIRCRAFT: B-52 #003 LAUNCH LAKE: Hidden Hills

PURPOSE OF FLIGHT: Aircraft Checkout & Stability at Low Angles of Attack

I. Discussion of Previous Operations

None II. Aircraft & Instrumentation Configuration Changes Reference X-15 Operations Flight Report Supplement dated 5/22/64. III. Preflight Events A. System functionals were conducted with several significant difficulties:
  1. Numerous helium leaks were encountered, and repaired.

2. Some components of the H202 system failed activity check. Nitric acid was used to passivate the engine tank and several lines.

3. Engine ground run was delayed an extra day due to minor but annoying incompatibilities with the GSE at the Test Stand.

4. Many errors were noted in the Data Systems wiring as delivered from NAA. These items added materially to the allotted time for Instrument Operations Technicians to prepare and calibrate the systems for flight.
 

 B. A planned captive flight (2-C-53) was conducted on Monday, June 15, 1964 with the following objectives achieved:
  1. Countdown thru igniter idle.

2. In-flight jettison test.

3. Landing gear cycle.
 

 This captive flight was invaluable in uncovering several discrepancies noted below.

C. Discrepancies noted during the captive flight were as follows:
 

1. Cabin pressure regulator failed to regulate. It was subsequently discovered to have been locked in the closed position during final assembly at NAA. Cabin pressure test during preflight would not reveal this error since the regulator is bypassed during this test. In the interest of safety the pilot was instructed to complete the captive flight with the Ram Air Door open.

2. The RH landing skid rotated far enough during the extension cycle to slightly damage its inboard lip against the main strut body. An increase in the capacity of the spring stop has since been made to decelerate the skid during the extension cycle, and prevent recurrence of this interference.

3. Engine helium source #2 indicated steady drop throughout the captive flight. A failed seal at the helium manifold was subsequently discovered.

4. Yaw damper failed to engage in flight. During the post-flight check, the yaw channel operated normally. A steel washer was subsequently found adrift in the SAS electronic case. However, no specific reason for the malfunction in flight could be proved. The entire SAS system was realigned.

5. Several T/M malfunctions were noted:
 

(a) #2 APU gearbox pressure

(b) NH3 pump inlet pressure

 IV. Flight Events A. An attempt to fly on Wednesday, June 17, 1964 was canceled after servicing due to high winds.

B. A second attempt made on Tuesday, June 23, 1964, resulted in an abort, when #2 APU failed to remain ON. Several attempts to start resulted in APU shutdown after approximately 5 seconds. After landing a controller check was made. Due to a procedural error the APU was inadvertently started with the controller disconnected and destructive failure of the APU occurred due to the resulting overspeed. Details of this incident are covered in a separate report.

Laboratory check of the controller showed it to be the cause of the in-flight shutdown. A new APU and controller were installed and the X-15 was again mated for flight on June 24, 1964. Helium #2 system again showed steady pressure loss, during this aborted flight. There is some ground for suspecting the external exposed location of the #2 sphere for this pressure decay. This sphere is subject to heating effects of sunlight while on the ground and severe chilling effects of altitude while in flight. Meanwhile, a continuing effort is being exerted to search out possible leaks. NAA Engineering is also making some study of this problem.

C. Flight 2-32-55 was successfully made on Thursday, June 25, 1964. The following discrepancies were noted:
 

1. Pronounced right roll out-of-trim condition, believed due to built-in warp of the RH horizontal stabilizer. The stabilizer will be replaced to eliminate the out-of-trim condition.

2. Radio reception on Frequency 286.8 was marginal.

3. Helium source #2 again showed pressure decay during the captive portion of the flight, although it was well within safe limits at launch.

4. Several data channel failures were noted after flight. Of these, angle-of-attack channel is probably the most serious from the research point of view. Turbopump RPM also failed to record.
 

 D. At present the vehicle is in work status for action on the above discrepancies.
 
  Approve By: Prepared by:

Perry V. Row William P. Albrecht

X-15 Senior Project Engineer X-15 Project Engineer