X-15 OPERATIONS FLIGHT REPORT

FLIGHT NO: 2-38-66 DATE OF REPORT: May 26, 1965

PILOT: John B. McKay DATE OF FLIGHT: May 18, 1965

CARRIER AIRCRAFT: B-52 #008 LAUNCH LAKE: Mud Lake

ENGINE: S/N 110

PURPOSE OF FLIGHT: (1) Main Gear Mod Checkout

(2) Star Tracker Checkout

(3) Stability and Control

I. Discussion of Previous Operations

A. The SAS system was given extensive frequency response tests as a result of the roll oscillations noted during flight 2-37-64. During these tests a check of the LH horizontal stabilizer actuator was replaced and subsequent tests showed a reduction in the roll residual with pitch engaged and roll disengaged, from approximately 1° to 1/8° surface deflection. As noted in item IV-D, this did not entirely eliminate the roll oscillations, and a change in SAS roll gain is being considered for the next flight.

B. The inertial system computer was replaced as a result of the altitude indication failure sustained during the last flight.

II. Configuration Changes None III. Preflight Events A. A "turn-around" preflight was initiated following flight 2-37-64. No engine ground run was made during this preflight.

B. A SAS frequency response was included with this preflight (see item I-A.)

C. APU runs were made on Monday, 5/3/65, but excessive vibration resulted in rejection of APU S/N 24. This APU was replaced with S/N 22 and APU preflight runs were completed on 5/4/65.

D. Mating with B-52 #008 was made Wednesday, 5/12/65. The inertial system computer failed and was replaced during the post-mate inertial check.

E. A flight attempt on Thursday, 5/13/65, resulted in abort (2-A-65) when the pilot's cockpit failed to pressurize after the inflight suit inflation check was completed. Subsequent inspection of the cabin pressure regulator revealed an Adel hose clamp wedged between the valve and its case framework. It is concluded that this clamp caused the valve to remain open during the flight attempt. This event was given widespread publicity in the hangar to emphasis consequences of carelessness. Demating was required to permit the B-52 to fly during the Armed Forces Day Air Show, (Sunday, 5/16/65.) The X-15 was remated Monday, 5/17/65, and flight 2-38-66 made Tuesday, 5/18/65.

IV. Flight Events A. Preflight servicing was normal. A ground jettison check was made.

B. A "high fuel pump pressure" shutdown occurred during engine igniter start. The engine was reset and a second "igniter idle" start was made successfully. Subsequent launch and engine start were normal. Inspection after the flight disclosed a stuck H2O2 metering valve in the pump control system. The engine will be replaced prior to next flight.

C. A higher than normal pressure build-up was noted in the NH3 tank prior to pressurization. He leakage through the NH3 regulator was suspected and post flight inspection confirmed this. The regulator will be replaced prior to next flight.

D. The roll oscillation noted on previous flights was again evident during this flight. (See discussion in item I-A above.)

Approve By: Prepared by:

Perry V. Row William P. Albrecht

X-15 Senior Project Engineer X-15 Project Engineer