Pilot - Joseph Walker
RESUME OF FLIGHT REQUEST
2. Maintain 10° a until q = 30°.
3. Maintain q = 30°, pushover to zero g at 39 sec., maintain zero g, switch to side stick.
4. V = 4600 fps, extend speed brakes.
5. Shutdown engine at 79 seconds. Set SAS 8-0-0.
6. V = 5,600 fps, gradually increase angle of attack to 10° and attempt to control airplane using b-dot technique if necessary.
7. V = 5,000 fps, reset SAS at 8-6-8, perform rudder pulse at maximum trim (a = 15°).
8. V = 4,200 fps, pushover to level flight at a = 6° and set SAS at 8-0-0. Control airplane using b-dot technique if necessary.
9. V = 3,500 fps, reset SAS 6-6-8, retract speed brakes and pull up to a = 8°. Perform rudder pulses while decelerating.
10. V = 1,700 fps, initiate turn to high key.
GENERAL POST FLIGHT COMMENTS -
1. The planned climb profile was not followed due to reduction in thrust during powered portion of flight.
2. SAS remained at 8-6-8 throughout the flight.
3. Pullup to a = 15° was attained and held above a = 10° for the deceleration from 3.7 < M < 5.0.
I. Launch (T = O - 10 sec.)
P.C. At launch, I flew by instruments. I had the sensation in the airplane of a kind of inplace yaw rather than much roll off. There wasn't anything more after that. I fired the engine and I am convinced I was already pulling the nose to establish the climb before the low inlet pressure light came on.
B. Please describe any system failures or adverse conditions caused by engine start.
P.C. The low inlet pressure light came on necessitating a reduction in engine thrust.
P.C. I had no problem on the climb-out, maintaining heading or attitude . I feel I paid very little strict attention to either one. I just kept that in one corner of my mind while I was checking engine operation. I was a little slow getting up to the right climb-out angle of attack. I don't feel I can give too good a tolerance rating to rotation and angle of attack after engine lightup due to being sidetracked with higher priority items. I was scanning the engine instruments and coming back to see how I was doing with angle of attack and sending my arm into action to pull the nose up and then going back to the engine again. Once I got on to it, I could hold a within 1.0°.
B. Describe longitudinal trim technique used for climb at constant q.
P.C. I used the trim button intermittently.
C. 1. Rotation a = 10° ±1.0°.
2. Climb attitude q = 30 ±5°.
3. Wings level ±5.0°.
4. Any course corrections during climb?
5. Any buffet? If so, please explain flight conditions.
P. C. No course corrections were made during the climb and SAS residual feed-back noted on the next item would mask buffet sensation.
D. Please describe any SAS residual motion feedback to control stick. Is roll or pitch difference discernible? Compare with simulator. Did SAS residual feedback influence flight plan?
P.C. I did get some residual feedback, but not in the control stick particularly, and in pitch only. I could feel it coming up through the system and I interpreted this as a synthetic buffet. Every time I would feel this start to pick up a little, I would haul back on the stick and it would drop off, so there was a feedback, I believe, but in pitch only. The feedback started during the initial rotation, after I had advanced the throttle. I'm not sure I noticed this at 50% thrust, but as soon as I started to advance the throttle, the residual feedback began and I had to keep pulling up. It kind of chased me into the 10° pullup quicker than I might have gotten otherwise. This residual is a combination of sound effects and feel but actually I think the sound is a little better tipoff than juggling in the stick itself. It is kind of a rumble coming through from the motion of the actuator.
E. Were any other distracting factors present
P.C. Yes, there were other distracting factors present. The distracting factor was the engine problem and the resulting reduction in thrust. Then having decided to go for full thrust again, the whole climb was immediately devoted to rapid mental calculations as to how the Sam Hill to get back on the planned flight profile again.
F. Please rate overall launch rotation and climb task.
P.C. Rating No. pitch, 1 , roll, 1, yaw 1
P.C. I flew center stick until I pushed down to zero g as planned, and switched to the side stick immediately on getting to zero g. I was trimming as required, but I think I was behind the trim the whole time. The technique I used was to clutch the stick in the center with my left hand while I was dropping my right hand onto the side stick. As soon as I assumed a grip on the side stick I moved my left hand over to get the trim switch changed from the center to side stick. I practiced this changeover reaching down to the trim change-over switch by feeling the guard over the switch, so I knew where the switch was. However, this time I couldn't find the thing but I was close enough to zero g trim so I could fly without further trim change until engine burnout, at which time I could get my head out of the vice, take a look down there, and turn the switch. I have never had any problem overreaching at zero g. Of course, with the engine running I am not at zero g, the acceleration vector is merely in a different direction; however, I still haven't had any trouble after engine shutdown. When I look at something I stick my hand at it and get it first try.
B. Did switching control sticks detract from monitoring the instrument panel?
P.C. No detraction.
C. Was effect of speed brakes noticeable on performance and stability?
P.C. Speed brakes were not opened until approximately one second before burnout .
D. Rate task during acceleration: (I) Rating No. speed brakes closed, pitch l 1/2, roll 1, yaw 1.
P.C. I would like to say that this added one-half in pitch is due to the fact that you have to pay more attention in order to change what you are doing and there is a little tendency not to be able to make the change and have it stay there without coming back a couple of times and rechecking after you have done it. (Changes in pitch attitude.)
E. Please describe instrument panel scanning sequence as engine shutdown approached?
P.C. The shutdown came before I was ready. I was watching the inertial velocity and altitude, and listening to callouts from NASA 2 (ground control). I decided as I went by 5,200 fps to start putting out the speed brakes, so I was keeping the zero g pushover, wings level, and on heading.
(1) What was primary cue for engine shutdown? Secondary? Were there any distracting factors? Was positive longitudinal g any better?
P.C. I intended to either go to engine runout or 5.600 ft/sec by the gage. Secondary cue would have been some callout from NASA 2, I think.
I noticed longitudinal g less on this flight than any other. I just busied myself around the cockpit taking notice of total velocity, inertial altitude, vertical velocity, and also checking pressure altitude part of the time.
(2) Vmax was » 5,300 fps.
(3) Did you have to correct for any burnout or deceleration induced motions?
P. C. I do not believe I had to correct for any burnout transients. I may have induced a pitch or roll motion inadvertently when I jerked forward at engine cutout because the airplane did start to wobble a little bit.
(4) Please describe any system failures to date during flight.
P.C. There were no system failures to this point in the flight.
(5) Other than instruments, are any new cues developing to indicate the airplane is traveling at high Mach number?
P.C. I have mentioned previously creaking and popping noises, but I believe I was actually slowing down before any creaking and popping started in the airplane or any smoke started rolling up in front of my nose. The impression I would get was that we were heating up with the airplane stretching and popping then quieting for a brief period of time as the smoke gradually thickened. As the smoke started to decrease and disappear, another set of creaks and bangs set in as though it started cooling down. It was, I think, very clearly a hot stove type of impression.
(6) Any noticeable heat effects?
P.C. Once again I was getting hotter from radiant type heating to the extent I reached over and adjusted my suit vent.
P.C. I started trimming up toward 15° a and as I went above 5° on toward 10°, I started to have more and more trouble with the airplane trying to. wobble, wallow in yaw. It appeared that we started by yawing and then we'd get a little bit of rolloff or as though we were poor directionally. I tried using a modified, b-dot to clamp the yaw down, but every time I attempted to go past an angle of attack of 10° toward 15° this got trickier. We were also troubled in pitch. I would try to raise the nose to a higher angle of attack, but the airplane would oscillate in pitch and I would have to wait and get it settled out to see where I was. Around a = 10°, the problem was every bit as severe or maybe more so, compared with the last flight I made. (SAS 0-4-8) Finally I did get the airplane steadied out at 10° and gave it a rudder kick and it started doing the same thing. My impression is that our yield in damping is certainly not consistent with the readings on the SAS dials about any axis. I repeat, a comparison of the airplane motion in pitch is very similar to the previous flight where SAS settings were 0-4-3. The roll was equally as poor or maybe a little worse, but I was more aware on this flight of the yawing around. The yaw mode impressed me as the one I had to pay strictest attention toward, but I wanted to stop the rolling in order to help stop the yaw as much as to maintain wings level.
B. Was deterioration in stability noted?
P.C. I was aware of the fact that the airplane kept not pointing in the direction I was going. I think the sun's shadow in the cockpit helped sharpen my perception of the nose going from side to side. I could tell without looking at the b needle.
C. Airplane was trimmed to full nose up trim?
D. What was a average using b-dot technique? 12° (modified b-dot used).
Did you vary a during this time period?
10°< a < 15°. Did b oscillation become progressively worse as M decreased?
D. What was b max noted on crosspointer? ±l.5°. At what period 4 sec? Did period change? No.
E. Describe and rate control task required to fly airplane using b-dot technique: Pitch 3, roll 3.5, yaw 3.5.
P. C. The control task was not real poor, I was able to do the thing but I had to work at it. I believe I could have made a reentry under these conditions.
F. Kinesthetic motion cues complicated greatly , somewhat , or very little X , the airplane control task compared with the fixed-base simulator?
G. Please compare X-15 and F-100 controllability, using b-dot technique.
P.C. There is absolutely no connection between this airplane and the F-100. I can't even correct the roll in the F-100 without getting slapped back and forth. In that F-100 you are sitting so high above the roll axis you can't do anything quick without knocking yourself loose. The center stick is a degrading part of the comparison too. If I were flying with the center stick on the X- 15 the comparison might be closer.
H. Please note any other distracting factors which complicated optimum airplane control during this portion of the flight.
P.C. Loss of proficiency might be considered. a distracting factor. If we ever get to flying oftener than once every 4 to 6 months it might make a difference. I actually believe we do not appreciate how much loss in proficiency we are suffering with this spacing between flights.
I. Please recommend cockpit instrumentation and control system changes which would facilitate using b-dot technique.
P.C. An error displacement type of instrument, sensing yaw rate, might be helpful.
J. Please compare emotional stress level reached during this portion of flight with launch, speed run and landing phases
P.C. I was calm as a cucumber. I had the feeling I was pretty busy during the climb. There wasn't any particular anxiety, it was just a case of trying to reset the mental calculator in time to do a good job.
K. Please comment on rudder pulses.
P.C. I was aware that the small rudder pulse made the airplane resume the directional oscillation experienced earlier.
L. Did stability improve as Mach number decreased?
P.C. Yes, I could feel conditions change as the Mach number decreased. I maintained a steady angle of attack for a long time as I was slowing down and you could feel the controllability becoming no longer any problem.
P.C. Over Saltdale at 85,000 feet altitude I couldn't see anything except way off to the side. I could see the Tehachapis running off down by Gorman but I couldn't see Mojave. I could see Los Angeles, but I could barely see the top of the San Gabriels. There was no problem of visibility other than mechanical limitations. I could identify anything that I could see but the nose out front was in the road. It's not the airplane nose that gets in the way since you can't see the nose of the airplane, it's the lack of windshield area. To see below me I banked to the right between 30° and 45°. At that point I could see the edge of the buildings down there, also the highway in Mojave. Then I felt that I was getting to the point where a turn was the best policy and I just rolled across into a bank into the other direction. The same thing occurred. Once I got turned over to about 30° there was no problem seeing, but as I decelerated and went into the pullout all kinds of problems occurred. My lid slid down covering my face, so I had to shove that thing up out of the road. I finally got cranked over to such a bank angle that the top of the canopy was blotting out where I wanted to look. So I rolled back up and then I could see very good.
B. Was an aiming point used prior to the flare? Please describe technique used.
P.C. I don't think there is anything you can say about that landing other than it was like shooting fish in a barrel. I came boring around onto a downwind leg high. I cross checked linear distance with respect to my aim point and was a little wider than standard. I think I snuck out a small amount of speed brake just by feel of deceleration more than anything else and dropped down a little on altitude. I pulled back in, turned on around onto a modified circular base and came up approaching the runway heading about 1,000 feet higher than I wanted to be so I touched speed brakes again just enough to feel them decelerating a little. When I got down to where I wanted to be, I shut them back up and went ahead with the flare. The first chevron quartet on the runway is the aim point.
C. What were cues used for determination of flare initiation point?
P.C. When I felt that I was on exactly the glide path that I wanted for the aim point I lowered the flap using altitude as a cue. The flare on this airplane consists mostly of holding down the nose so that all I was doing was checking my occlusion rate with the ground. Actually flare initiation comes coincident for me with the initiation of putting the flaps out. From that point I'm ready to decrease the vertical velocity. When I decided I wanted the gear out, I put the gear out and eased it toward the ground.
D. Was spot landing attempted? How far from planned point was touchdown?
P.C. I have been informed that I touched down right at the 2-mile spot.
E. Were aero controls used successfully for run out control?
P.C. I've been requested to maximum effort stop and I accomplished this except that I had a little trouble holding the stick back against the stop. I yanked it back and it drifted forward, so I pulled it back again. The airplane went straight for a little way with no difficulty at all. Then it seemed to crank up out of the wind about 10 or 15° and I tried to pull it back. The best I could do was to keep it from turning any further with the rudder in the direction I wanted to turn or out of the direction I wanted to turn or in line toward the direction I wanted to turn. With the stick all the way back I only had half as much as I needed anyway.
P.C. I do not think the flight objectives were obtained as written on the flight request. However, I feel we have some valuable information. I don't feel we have any reason to preclude going to a higher velocity since we can go to it without having to shoot into a tremendous angle of attack.
B. Other than kinesthetic cues, please note briefly airplane control characteristics which were not encountered on simulator.
P. C. Motion as experienced in flight could be simulated only by switching to very low SAS settings and holding a higher angle of attack. The period of the directional motion was shorter on the simulator in all cases.
C. Do you have any comment for improving ground control?
P.C. The only valid comment for improvement in ground control would be that in the event it is obvious a recommendation must be countermanded, a strong negative should be introduced in order to wipe the slate clean and then verify that your new recommendation has been received. Also, although the timing callouts were not exactly applicable due to thrust changes, they gave me a clue as to how far behind I was and I could vary the climb accordingly.