X-15 OPERATIONS FLIGHT REPORT



FLIGHT NO: 1-36-57 DATE OF REPORT: 7/8/63

PILOT: J. A. Walker DATE OF FLIGHT: 6/25/63

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

PURPOSE OF FLIGHT: 1. Induced Turbulence with KC-1

2. Development of Traversing Probe

I. Discussion of Previous Operations

A. Inspection of nose gear detail parts and compartment following the in-flight inspection door opening was completed and areas of serious heat damage are listed in the following:
  (l) Airspeed compartment panel (nose wheel well forward bulkhead) was severely distorted by heat with failed inspection-door-hook support brackets.

(2) Distortion and melting of the wheel fender (added by ECP-15-155 to protect the KC-l window during landing rollout).

(3) Inspection door hinge, made of aluminum, was partially melted. Mating hinge points on main door were distorted by the force of airloads.

(4) The nose gear strut assembly was heat soaked as evidenced by blistered aluminum paint.

(5) The tire fragments recovered from the lake were charred (although the tires were still inflated on landing).

(6) Evidence of melted Cadmium plating on uplock mechanism and discolored zinc chromate paint on many aluminum parts.

 The air, scooped up by the open door, impinged directly on the fender. From there it flowed forward against the F-7 panel and then circulated upward and to the rear of the compartment. The majority of the parts of the gear mechanism were replaced, the inspection door was rebuilt, and the inspection door hinge attach points on the main door were replaced at NAA-LAX.

B. The characteristic fuselage buckling encountered on the other X-15's during heating type profiles were noted following flight.

C. Hi-shear rivets at the station 91 frame have had a history of sporadic failure; the third rivet failure on X-15-1 was experienced during the previous flight. Repairs are made with the next size stainless cherry rivet milled down to skin contour.

D. On the previous flight, thermo paint was applied to the windshield frame and extended one-half inch onto the glass perimeter. Postflight conditions indicated no local heating on the rear glass edge, however, local heating on the radius of the canopy frame was indicated.

 II. Aircraft Configuration Changes A. A revised APU gearbox pressurization system was installed to prevent gearcase oil from entering the LN2 system. The gaseous nitrogen supply swing-type check valve was replaced with a spring-ball poppet type, and two swing-type check valves and an oil accumulator were added between the regulators and gear cases. The system relief valves were relocated to the accumulator to prevent gearcase oil chilling if relief valve or regulator malfunctions occur.

B. The nose gear inspection door configuration was modified per EO-870025 which stiffens the hinge attach points and differs from NASA Sketch #776 in that the original aluminum inner skin is retained instead of replacement with Inconel X.

 III. Instrumentation Configuration Changes A. Recording of the engine vibration was added to the Parsons tape recorder parameters to provide an in-flight capability.

B. The traversing probe on panel 69 was reworked to provide .020 clearance between the total pressure tube and panel in the retracted position. This modification is intended to prevent seizing due to high temperature distortions.

C. The telemetering Neff power supply was relocated from the elevator onto the forward middle elevator compartment shelf to eliminate system voltage drop.

D. Additional control box capacity was added to reinstate the SAS pitch servo and longitudinal trim CPT's.

 IV. Preflight Events A. Engine S/N 107 was qualified for flight without a ground run, however since more than 30 days had elapsed since the last operation, a preflight ground run was accomplished. The run was satisfactory.

B. APU S/N 16AN was removed for X-15-3; replacement APU S/N 25AN was installed in the #l position and qualified for flight.

C. The inertial system computer, S/N 1, which incorporates external DC source wiring was installed for flight evaluation. Post-mate checks revealed inadequate B-52 wiring, and unacceptable DC voltage levels were obtained. The computer was replaced with S/N 3, an unmodified configuration.

 V. Flight Events A. Fuel was off-loaded to 2° 22' nose-up attitude and a fuel depletion burnout was experienced. During the last portion of the operation the engine was decelerated in 5 seconds, held at idle for 15.5 seconds, then accelerated to 100% in 1 second, with burnout at 100%. Total engine time was 94 seconds.

B. A cabin source drop greater than normal usage was noted prior to launch and indicated leakage. Launch was made with 2650 pounds per square inch pressure, and the flight was concluded with 1050 pounds per square inch pressure.

C. The nose gear performed satisfactorily in all respects. Smoke in the cockpit was noted during the flight, and evidence after flight indicated the rear edge of the nose gear door continues to deflect under air loads, allowing air to impinge on the forward cockpit bulkhead heatshield and circulate in the aft portion of the nose gear well.
 
 

 Approved by: Prepared by:

Perry V. Row Ronald S. Waite

X-15 Senior Project Engineer X-15 Project Engineer