X-15 PILOT QUESTIONNAIRE

FLIGHT 2-20-36

Pilot - Major Robert White

RESUME OF FLIGHT

1. Launch using side controller, light engine at 75% for approximately 5 sec., then advance to 100%, rotate to 10°a.

2. Hold 10°a until q = 32° for climb.

3. At t = 33 sec., extend speed brakes.

4. At t = 79 sec. shut down engine, pushover to a = 0° and maintain a = 0°, b = 0° using ballistic controls.

5. At peak altitude, rotate to 5° a using BCS. Maintain for approximately 10 seconds, then reduce to 0°..

6. At 180,000 feet, trim stabilizer to 20° by stabilizer quadrant in cockpit and establish trim a of approximately 14° using BCS.

7. When level, (Qmax » 4.0, Axmax = 1.7, qmax » 1,000 psf), perform rudder pulse, retract speed brakes and perform pushover-pullup.

8. Perform space-positioning turn towards high key.

EXIT PHASE

I. Launch

A. Please compare launch and recovery with previous flights.

P.C. I wouldn't have any comments on this because there was nothing different from previous flights where I have launched on the sidestick.

B. Please describe any system failures or adverse conditions caused by engine start.

P.C. There were no system failures or adverse conditions caused by the engine start. Everything was positive, smooth and rapid.

C. Simulator: a rotation 10° ±0°.

Climb 32° ±0°.

Wings level 0 ±0.

(Note: Pilot rated longitudinal control task for recovery and rotation to climb attitude as 2.)

Airplane: The rotation to 10°a was fairly rapid after getting the 100% engine thrust and was held right on according to my indicator. The climb q was 32° and might have bobbled just a little bit, but it was essentially constant all the way. The wings were level all the way. Once during the climb the controller called to right of track. I did make a brief attempt to correct the yaw and then leveled the airplane back up.

D. Please describe any SAS residual motion feedback to the control stick and compare with simulator stick motions. Did this feedback influence the climb profile?

P.C. As far as SAS is concerned, I did not detect any residual motion and the comparison with the simulator was excellent. As far as influencing the climb, nothing was very different from what was practiced with the simulator.

E. Were any other distracting factors present during the climb out?

P.C. After the speed brakes were extended I seemed to be impressed with the longitudinal acceleration more than I had been on previous flights. The g level was approximately 3 1/2 (data). Previously I felt I was back against the headrest and seat and fairly comfortable, held back nice and snug, but on this particular flight I definitely could feel that there was what appeared to be a bit more push.

F. Please rate overall climb task.

G. What were cues used for determination of engine shutdown point?

P.C. Simulator: Time first, velocity second.

Airplane: The cockpit stopwatch did not operate. Primary cue was time from ground callout with cross check to the velocity indicator. The shutdown point in time as compared to altitude was the main cue used on the simulator and I used this for the flight.

H. Were any distracting factors present at engine shutdown? Were there any system failures?

P.C. Yes. Just about the time we were getting close to 75 seconds, I started to get some wandering in sideslip, (The needle went to the right indicating right b)J and a little in bank angle and I was impressed that my response in the aerodynamic control seemed to be less than at the lower altitudes, so I instinctively put my hand on the reaction control stick and about this time the ground controller started counting 76, 77, 78, 79. I reached for the throttle and burnout occurred. I did not close the throttle.

I. Vmax, h burnout?

P.C. I did not notice the velocity, but the inertial altitude indicated about, 124,000 feet.

J. Did you have to trim for the speed brakes?

P.C. No.

BALLISTIC PHASE

I. Pushover

A. Describe the trim technique used during pushover.

P.C. Simulator: Trim used and practically no force. Airplane: I started trimming toward zero on the stabilizer as the inertial height indicator went to 140,000 feet. I then looked at it and trimmed right to zero.

B. Could the effect of decreasing q be noted?

P.C. Very definitely. The airplane started wandering around quite a bit particularly in a.

C. Was a steady or oscillatory?

P.C. Simulator: Steady. Airplane: a was fairly oscillatory after I went through 150,000 feet.

D. Was lack of aero damping noticed at this point?

P.C. Simulator: No. Airplane: Yes.

E. When was each BCS system activated?

P.C. Simulator: During climb at 0° a after power off.

Airplane: During the pre-launch BCS check.

F. Did system function properly?

P.C. Yes.

G. Were BCS pressures monitored during flight?

P.C. No.

II. Zero g A. Please describe onset of zero g.

P.C. No comment on zero g.

B. Did zero g aggravate the control task?

P.C. There was no trouble.

C. Please describe airplane motions at low q.

P.C. The airplane started wandering around particularly in a and here is where I had a problem and a confusing influence as the flight developed. a was fairly oscillatory after I went through about 150,000 feet, then I started using reaction controls to make corrections. It .seemed like the bank angle would just wander a little bit and I would make the correction to get it back to zero easily and did not have to pay too much attention to it. Sideslip would occasionally start to wander off and this was similar to the simulator because sometimes it would start to go off and look like the rate was picking up so you put in the control and are able to stop it and then bring it back. I felt I could control things nicely except for the angle of attack. This introduced some confusion when I got to the entry. On top, the changes in the attitude of the airplane were very apparent. One time, I came down through the horizon and went to a -a. I made a correction for that and then the needle shot up and the airplane pitched up quite significantly so that I could pick this change up by looking outside. By making another correction I was able to get it back down. At the time when I got on top, I kept reminding myself to make the a = +5° change as called for in the piloting task. I did not perform the task exactly as specified and soon gave it up with the problem in pitch and started to prepare for the entry.

NOTE:

NOTE: The horizontal crosspointer was set to null at a = 10°, the flight plan called for a = 0° null position. The airplane stabilizer was trimmed for a = 0° and the pilot was using the reaction controls to oppose the aerodynamics and thus the confusion as the motions were illogical and did not match that of the simulator.

D. Please discuss reaction control effectiveness about each axis.

P.C. Simulator: Excellent in pitch and yaw. The response is slow in the roll mode. Airplane: The reaction controls were more responsive. There was more thrust coming on faster when you moved the handle. Yaw matches the simulator very well and roll is just about the same. In pitch, the nose was following when the control was used.

E. Was crossover from aero to reaction controls sharply defined?

P.C. Simulator: No.

Airplane: Yes.

F. Were control inputs pulse type or proportional?

P.C. Simulator: Both.

Airplane: I'd say they were the pulse type, however, the roll inputs were more proportional.

G. Was any coupling motion noticed?

P.C. Simulator: Yes.

Airplane: No.

H. Please estimate maximum angular rates experienced about each axis.

P.C. Simulator: The rates were very low.

Airplane: No comment except they were higher in pitch.

I. Were aero controls used at low q? Was stabilizer retrimmed?

P.C. Simulator: No comment. Airplane: I had one control stick in each hand and one time, just inadvertently I suppose, it might almost be a normal reaction. I used lateral aero control for a bank angle correction. This did not have any effect and it registered that I should leave the aero. controls alone. There shouldn't be any motions in the pitch aero control. The trim was run to zero degrees and left alone.

J. Please rate pilot control task at low g.

P.C. Ballistic flight to apogee: Pitch 2, roll 3, yaw 2. Apogee to initiation of entry: Pitch 4, roll 3, yaw 2. Airplane and simulator ratings are the same.

K. Was simultaneous control input required about more than one axis?

P.C. Simulator: Yes. Airplane: One axis was controlled at a time.

L. Was control task performed leisurely or hurriedly?

P.C. I'd say it was leisurely in roll and yaw and a little more hurried in pitch.

M. Please estimate lateral and longitudinal period.

P.C. Simulator: Very long - above 10 seconds. Airplane: Very long. (At min. lateral and longitudinal periods were above 15 seconds).

N. Was H202 conserved at the expense of larger airplane motions ?

P.C. No.

O. What was peak altitude? What was velocity at this point? How was apogee determined?

P.C. Peak altitude and velocity were not noticed. I could see the horizon and tell when I was level or at the apogee .

P. What did it look like?

P.C. It was lovely.

Q. Was onset of negative pitch rate during trajectory noted?

P.C. You could see the negative pitch after burnout.

R. Did negative pitch rate complicate the longitudinal control task?

P.C. No.

S. Was the reaction control stick configuration adequate and comfortable?

P.C. Yes.

T. Were the stick forces acceptable?

P.C. Yes.

U. Please comment on the dead band.

P.C. No comment.

V. Was the half detent noticed?

P.C. No.

W. Please describe lag between control input and airplane response.

P.C. I wasn't impressed with any lag at all. I thought the response was very good.

X. Was the proportional control input feature noted and used?

P.C. The proportional features were used in the roll mode only.

A(1) Was 3-axis ball with crosspointers adequate airplane attitude presentation for this flight?

P.C. Yes.

B(l) Were the crosspointers flown to the null position?

P.C. Yes.

C(l) Was the absolute a meter monitored during the reaction control portion of the flight?

P.C. I would cross check this, but I was primarily on the crosspointer.

D(l) Did kinesthetic cues during ballistic flight provide sufficient feel to enable the pilot to lead the airplane's motions?

P.C. Yes. The motion cues helped quite a bit, particularly over the top. During some of the a excursions, I could look out and actually see some of the pitch angle changes and one time I made a correction in pitch looking out the window as a reference.

E(l) Was outside vision good?

P.C. Yes. The outside visual reference was good.

F(l) Were there any lighting problems on the instrument panel?

P.C. There were no lighting problems on the instrument panel.

ENTRY PHASE

I. Reentry

A. Could q onset be detected through change in motion period?

P.C. Yes, and this was indicated by the way everything stiffens up.

B. What was primary cue used for starting entry maneuver?

P.C. Simulator: Altitude.

Airplane: Altitude, comparing the inertial altimeter with the radio callout at 180,000 feet.

C. To what minimum altitude was BCS used? Was BCS system turned off?

P.C. Simulator: BCS was used down to 130,000 feet.

Airplane: I am sure I did not use the BCS below 150,000 feet. I did not turn the BCS system off.

D. Was the crossover point from BCS to aero controls sharply defined?

P.C. Simulator: No.

Airplane: I could not sharply define the crossover point from the BCS to aero controls.

E. Please describe preparation for atmospheric entry.

P.C. Nothing more to describe than just setting up the stabilizer trim and trying to maintain angle of attack.

F. Please rate control task during early part of entry.

P.C. Simulator: Pitch 2, roll 3, yaw 3.

Airplane: Pitch 2, roll 2, yaw 2.

G. Please describe reentry maneuver.

P.C. As I came below 180,000 feet, I just looked down to the stabilizer quadrant, reached back and rotated the wheel to what I thought was 18° on the stabilizer. The angle of attack came up to about 10° and ran steady. I did not damp the trim after the initial setting. The buildup in aerodynamic control was very noticeable; once the g started coming on it was very solid. I did back off a little bit to hold it, after 4 g and then from the ground callouts I could tell I was going to go a bit lower, but I wasn't impressed that it was going so much lower that we had any problems as far as driving to too high a q. There was no residual, at least as far as giving me any concern.

H. Was there any b oscillation?

P.C. Yes. After the q built up. It didn't bother me.

I. Was the descent angle and rate alarming?

P.C. No, it was alright. I could look out and see the whole valley - the lake, Rosamond and other places.

J. Did you feel the 11° a was adequate for entry? Why didn't you pullup to 15°a?

P.C. I knew the 11° was adequate. I guess you often wonder why the pilot doesn't go back to the angle of attack he was looking for, but when you have a good stabilized condition and this is adequate to get through the entry or anything that you are going to do, I think you are inclined to accept this and go ahead as long as things are good instead of making a sharp change in stabilizer settings.

K. Please describe acceleration vectors.

P.C. There was 4g normal and this seemed to be on for a fair while and then I could notice the Ax and this became impressive also. At one time Ax seemed to increase suddenly and the force pushing on the helmet caused a slip and my head was somewhat down under the head bumper. It wasn't uncomfortable so I left it alone. There were no surprises as far as any of the accelerations are concerned.

L. Please rate control task required to complete entry maneuver.

P.C. Simulator: Pitch 2, roll 3, yaw 3.

Airplane: Pitch -, roll 2, yaw 2.

II. Space Positioning A. Could the lakebed be seen from high altitude?

P.C. Yes, once you get the nose down a little bit you can look down and see everything.

B. Were any course corrections made from this visual observation?

P.C. No. I was off to the right of the lakebed and that was adequate.

C. Please describe instrument panel scanning technique as level flight was approaching.

P.C. I was mainly on g here, and checking altitude as I was descending and coming level.

D. Was instrument presentation adequate for entry?

P.C. Yes.

III. Landing Phase A. Any visibility problems navigating back to base, in the pattern or during the flare?

P.C. None at all and that includes the cracked windshield.

B. Was an aim point used prior to flare?

P.C. Yes, I used the same technique as before except I let myself get a little bit low going from downwind to base leg so I know that I was going to be a little bit short before I even crossed the end of the runway.

C. Please describe flare technique used, noting cues used for flare initiation and flare initiation point relative to ventral jettison and flap actuation.

P.C. The flare technique, flare initiation point, ventral jettison and flap actuation, they were all exactly the same as I have used in the past except I did not fly the same pattern.

D. Flare initiation point Vi = 300 knots, hp = 500 ft above the ground.

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

P.C. Yes, but it was abandoned on the final approach because I knew I was going to be short. You get beyond a certain point and you cannot correct. This point is about on the base leg. You can pretty well tell there what is going to happen. I could perhaps have slowed down a bit to a more ideal approach speed for increased range but had no imperative feeling to do so.

F. What would you estimate for touchdown speed?

P.C. 180 knots.

G. Did you notice any ground effects? How would you compare it with ground effects in other low L/D vehicles like the F-104 for instance?

P.C. You might have except when the flaps are lowering you get a trim change and this picks you right up in the air and I think it gets you out of the ground effects and I don't feel any significant influences.

IV. Simulation A. Please compare flight with simulator preparation.

P.C. Very favorable.

B. Indicate adequacy of ground control for this flight.

P.C. Ground control was good except for communication difficulties. This trouble was continuous until I was in the Edwards area.

C. Are airplane instrument panel presentations, aero and reaction controls, piloting techniques and trajectory control techniques adequate for next step in envelope expansion?

P.C. Yes, except I think it would be worth while to look into the pitch reaction control. Even with this trouble we could still do a high altitude mission.

D. Could you be a little more explicit as to when the window cracked (left window).

P.C. I had come off the high g. I was level at about 60,000 feet and between 1.6 and 1.8 on the pressure sensing Mach meter. It cracked all at once. I could notice little slivers of glass falling away once in a while.

E. Was the emotional stress level higher on this flight?

P.C. No. On that score I think emotional stress levels will go up by a factor of things that fail in the airplane. There is nothing really to get excited about. You are just doing what you have been practicing all the time on this mission and wrestling with the little tasks as they show up if they are a little bit different and you may expect them but, if things start failing, or the suit blows up or SAS goes out why then I think you might talk about emotional stress levels.