X-15 PILOT QUESTIONNAIRE - FLIGHT NO. 1-22-37, August 10, 1961

Pilot -- Cmdr. Forrest S. Petersen

I. Launch (t = 0 - 10 sec. )

A. Please compare launch recovery techniques used on this flight with previous flights.

P.C. No change. Failure of launch switch caused a delay in launch and caught the pilot unawares. Roll control input apparently caused a slight left course deviation after launch.

B. Please describe any system failures, and resultant airplane control task at launch or after engine start.

P.C. The delay in drop of several seconds with the auxiliary launch held switch closed caused the pilot to conclude that an auxiliary launch could not be made. Simultaneously with this conclusion, drop occurred unexpectedly. As a result there was some delay in getting the engine started. NOTE: The entire flight was made on the center stick.

II. Climb ( = 10 - 58 sec.) A. Please describe longitudinal trim technique used for climb and indicate if in your opinion this is optimum technique.

P.C. It was intended to make all except the most gross longitudinal control changes during establishment of the climb with the trim system. However, the pilot got behind the required control inputs using trim alone and had to use forces in addition. The aft stick required to establish a 12° a climb was greater than anticipated from. simulator practice. This may have been accentuated by pressure suit bulk.

B. Please comment on longitudinal trim characteristics in. range 1.0 < M < 1.6.

P.C. Here again, the pilot got behind the aft control inputs required and had to use aft force as well as trim in an attempt to keep the desired climb a.

C. 1. Rotation a was 10 ± 2°?

2 . Climb attitude was 30° ± 1°?

3. Wings were held level ± 2°?

4. Were any course corrections required during climb?

P.C. Yes. 5° right .

5. Was buffet noted during rotation and/or climb?

P.C, No

D. 1. Please describe SAS residual motion feedback to control stick. Compare with motion experienced on simulator. P.C. None noted.

2. About which axis, or axes was residual motion discernible?

P.C. None

3. Did SAS residual feedback complicate the climb control task?

P.C. No

4. Were any other distracting factors present?

P.C. No.

E. Please rate overall climb task.

Rating No. in pitch 3; roll 3; yaw 3.

III. Acceleration to Vmax (t - 115) A. Rate pilot task during acceleration to Vmax, and describe airplane controllability.

Rating No. in pitch 3; roll 3; yaw 3. Up to pulses.

Rating No. in pitch 3; roll 3; yaw 3. After pulses to Vmax.

P.C. Dead beat on pulses.

B. Adjustment of trim X, was preferred for longitudinal control during pushover.

C 1. Please describe instrument panel scanning sequences during this period of the flight. P.C. 3-axis ball - Vinertial - 3-axis ball - a

2. Please describe cross checks between clock, inertial vel., inertial altitude, and ground call out.

P.C. Clock - right on

Vinertial - right on

Hinertial - one check at 70,000 inertial when ground call out was 78,000. D. Was sufficient time available to anticipate engine shut-down point?

P.C. Yes.

1. Note cues used in sequence for determination of shut-down point.

P.C. Shutdown was on ground call out. The cockpit clock was close, but was not specifically checked. 2. Were any distracting factors present?

P.C. No.

E. Vmax was 4100 fps?

P.C. On inertial cockpit indicator.

F. Did you have to correct for any burnout transient motions?

P.C. No. Also, no transients when engine was started.

G. Please describe any engine failures, and resultant airplane control task at engine shutdown.

P.C. None

IV. Airplane control using b-dot technique (t - 200 to 260) A. 1. What was amax using b-dot technique?

P.C. 6°. First noticed suit was blown up when pilot reached forward to turn off dampers,

2. What was aaverage using b-dot technique?

P.C. 6°

B. Describe and rate control task required to fly airplane using b-dot technique.

P.C. The airplane established itself in a directional oscillation of about 4° - 5° magnitude with the pilot attempting to make no control inputs and without increasing a above the trim value at burn out. The directional oscillation was sustained and no attempts were made to damp it. During the deceleration from M 4 to 3, it became apparent that the oscillation was being fed by airplane motions through the pilot control loop. He removed his hand from the stick and the next two or three cycles were obviously damped. When he took hold of the stick again the oscillation again built up. By this time the airplane was below the uncontrollable region.

NOTE: Pilot would have made entry at the condition. Pilot described lateral accelerations as not being smooth but more like a square wave input. He compared them to fuel sloshing in an F-104 with yaw damper off.

C. From this flight experience, how useful is b-dot technique for extended emergency operation of airplane?

P.C. Not applicable to this flight. The conditions experienced would be satisfactory during the distracting influences of reentry.

D. Kinesthetic motion cues complicated greatly _____, somewhat __XX_ , or very little_____, the airplane task compared with the fixed-base simulator?

E. Please compare X-15 and F-100-709 controllability using b-dot technique.

P.C. For the angle of attack, Mach number, q range of the oscillation experienced during this flight the simulators are quite steady and do not fly at all like the X-15. Further the roll oscillations experienced on the simulators at higher angles of attack in this area are much greater than the roll oscillations experienced in the X-15 on this flight. During this flight the roll oscillations were of no concern.

F. Please note any other distracting factors which compromise optimum airplane control during this portion of the flight.

P.C. The airplane tended to roll off to the right during the initial part of the oscillation. This was corrected by small conventional lateral control inputs. Suit being inflated did not cause too much concern.

G. Please recommend cockpit instrumentation. changes which would facilitate using b-dot technique.

P.C. None

H. Please compare emotional stress level reached during this portion of flight with speed run and landing phases of the flight.

P.C. They were about the same with the pilot paying particular attention to any tendency of the directional oscillation. to diverge.

V. Landing (t - 500) A. What were cues used for determination of flare initiation point?

P.C. 3,000 ft. observed pressure altitude

1. Flare initiation point v1__320__, and Hpc - 3000

2. Flare initiation point relative to ventral jettison and flap actuation was _____?

P.C. Flare occurred considerably ahead of ventral jettison and just ahead of flap actuation.

B. Was an aiming point used prior to the flare? Please describe technique used.

P.C. The one mile marker was used as an aiming point prior to flare initiation. Flare was initiated at 3,000 ft hpo and flaps were dropped at 300 kts. Gear was extended at 260 kts.

C. Was a spot landing attempted? How far from planned point was touchdown?

P.C. The pattern was flown to accomplish landing at the 2 mile marker. However, after the gear was extended the only criteria considered was accomplishment of a smooth landing. Landing occurred 800 ft beyond the 2 mile marker, Landing could have been accomplished earlier or later had it been. necessary.

D. Were aero controls used successfully for runout control?

P.C. Past landing controls were full aft longitudinal control, speed brakes out, flaps up. Towards the end of runout some right rudder control was used to correct a slight tendency to turn right.

VI. General Observations A. Please note briefly the major deficiency noted during this flight .

P.C. The major discrepancy uncovered by this flight is the fact that X-15 oscillations in flight are not simulated by the X-15 simulator.

B. Other than kinesthetic cues, please note briefly airplane control characteristics which were not encountered on simulator.

P.C. The oscillations encountered are non-existent in the simulator at the flight conditions. Pilot commented on actual flight being more crowded time wise that simulator flights.

C. Would addition of engine and system instrumentation to simulator improve flight simulation?

P.C. Only if incorporated to such a complicated degree that system failures can be realistically simulated. The advantages to be gained by this are outweighed by the cost and effort required.

D. How effective was ground control in executing this flight mission?

P.C. Excellent.

P.C. Note: Mild buffet was noted decelerating through M - 1.2 to M - 1.1, hp - 35,000. feet, a 10 to 12,