NASA FRC
May 17, 1963

To: Chief, Research Division

From: Vehicle and Systems Dynamics Branch
Subject: Preliminary Report of X-15 Flight 3-17-28

Flight 3-17-28 was flown on May 14, 1963, by Major Robert Rushworth for the purpose of:

1. Heat transfer at high Mach number and high angles of attack.

2. Infrared and ultraviolet experiment.

3. Investigation of lateral-directional stability at low angles of attack at Mach 4.

 A preliminary review of the flight records indicates that these objectives were accomplished essentially as planned. The flight profile was not flown as planned because of an engine malfunction shut down one second after initial start. A satisfactory engine restart was accomplished 13.5 seconds after drop. There were no other failures or malfunctions during the flight. The maximum altitude and velocity were approximately 95,000 feet and 5,050 fps respectively. Reaction controls were not used during this flight.

Heat transfer data was obtained just prior to engine shut down at a velocity of about 5,030 fps during a high "g" turn and maximum angle of attack of 19°. Semi-steady conditions were maintained for only about 6 seconds.

Rudder pulses were performed with the roll and yaw axis dampers on fixed gain while decelerating from about Mach 4 to Mach 3. For these pulses, the angle of attack was about 2°. The pulses, conditions, and comments are listed below.

Speed Brake a b max T 1/2 (r)

open -2° 2° -1.1 sec.

closed -1° 2-3° -1.1 sec.

20° -1.5° 2-3° -.8 sec.
Pilot reported good damping, much better directional stability than on previous similar flights.
The landing was made without incident and the data indicates lighter loads than on the previous flights. Slide out distance was 7,700 feet.
 
 

Elmor J. Adkins

Aerospace Engineer