|Pilot:||Neil A. Armstrong||Launch:||1127|
|Launch A/C:||B-52 #008||Land:||1139|
|Launch Panel:||S. P. Butchart|
Prelaunch checks were satisractory with no discrepancies outstanding. The MH-96 airborne analyzer check was completed without railure with the exception or a temporary failure indication on center stick, fixed gain, trim output. The analyzer performance was particularly comendable in view of the fact that the B-52/X-15 combination was encountering severe turbulence with significant roll and yaw excursions during the entire analyzer operation. Inasmuch as normal doppler operation was never achieved, NASA 1 predicted inertial velocity would include a small error.
The launch was performed with 4° left roll differential stabilizer, the trim value with the MH-96 flight control system engaged. Right roll at release was moderate with a total bank angle change of approximately 20°. A 100% throttle start provided smooth engine ignition with no significant transients. The pullup was performed with 3 units of side stick, nose-up, rate trim. Angle or attack during the pullup varied between 7 and 10 degrees. Roll hold was engaged at approximately 1500 fps without transient. Pushover was accomplished with full nose down trim (side stick) at 35 seconds and approximately 31° pitch angle. Angle or attack after the pushover had been stabilized varied from 0 to 2 degrees.
Inertial velocity at 50 seconds indicated 3100 fps (about l00 fps over predicted). Inasmuch as engine chamber pressure (570 psi) was below predicted (590 psi), engine thrust, acceleration, and total velocity should be slightly low. It was therefore assumed that inertial velocity was in error as predicted and was indicating slightly high. It was decided to perform engine shutdown at the planned time ( 81 sec. ) insuring no over velocity.
The second pullup was performed with 5 units or nose-up trim at 55 seconds. Trim was reduced to zero as the specified 32° pitch attitude was approached. Pitch attitude hold was engaged without significant transient. Longitudinal damping at this flight condition (V=4500 rps, h=100,000 ft) was particularly good in opposition to the simulator predictions. Reaction control energizing was selected in the automatic mode and was not detected; hence it is not known whether some of the damping can be attributed to reaction controls.
Flight path angle was reported to be slightly steep at 75 seconds although pitch attitude was 1° low (31°). Q was maintained at this value through shutdown at 81 seconds. Indicated inertial velocity at shutdown was 57-5800 fps and was suspected to be indicating several hundred fps high. Radio reception subsequent to this point throughout the high altitude part of the flight was intermittant. Voice relays through the B-52 were partially successful.
Control stick steering was used to reduce the angle of attack to near zero at which time the angle of attack hold was engaged without transient. Cross checks of inertial altitude and inertial vertical velocity indicated the trajectory to be precisely as planned. Inertial altitude at the trajectory peak was indicated to be 210,000 ft. The pitch attitude outer loop was reengaged at this point, and was accompanied by a slight shudder through the fuselage. Yaw and roll overpowers were performed on both a and Q hold. The returns were at modest rate with little evidence of overshoot. Overpowers on the aircraft require considerably more stick or rudder deflection for a specified aircraft motion than on the simulator.
Angle of attack hold was engaged at 175,000 feet and approximately 15° alpha, and was again accompanied with a slight shudder. The angle of attack reference was increased to 21° with the vernier. Roll overpowers were performed with the airplane response again being more sluggish and accompanying sideslip excursions less than one half the magnitude of the simulator.
In general, aircraft control and damping during ballistic flight and entry were outstanding, and considerably more smooth than had been expected. Unfortunately, this may be at the expense of excessive reaction control fuel consumption. The #1 APU/BCS H2O2 low lite was illuminated at approximately 160,000 feet during the descent. The H2O2 transfer system was immediately energized and the light was extinguished at approximately 115,000 feet.
The control stick steering button was engaged at 120,000 feet to resynchronize the outer loop references. Some attitude drifts were experienced during this period. While normal acceleration was increasing to 4, angle of attack was reduced to 16°. This value was maintained in an attempt to observe the "g" limiting function in operation. Such limiting was not observed.
Although speed brake extension and angle of attack reduction were thought to be performed as scheduled, it soon became obvious that some positive flight path angle had been achieved subsequent to the entry completion. This flight condition (v=4,000 fps, h=85,000 ft, gamma= +), compounded by an entry completion 20 miles further down range than predicted, created a situation which precluded the completion of the flight path as planned. A sizeable overshooting of the space positioning turn required a straight~in approach to an alternate runway (35).
Handling qualities during the flare were considered
to be less desirable than on previous similar approaches. Large stick
motions were required and response in pitch was sluggish. Flight
data indicated the control system gains had been driven to low values.