PILOT COMMENTS AT DEBRIEFING AFTER X-15 FLIGHT 2-15-29 ON APRIL 21, 1961

White: After take-off we went on up. Everything seemed to go along pretty well, as far as I was concerned. I got verification on all the BCS cycling from chase. We finally got the LN2 on, and we were up pretty close to 45,000 feet, and with the ram air door closed and blowers only, I continued to pressurize in the suit up to that level. Got LN2 on, pressure cooling on, and came down and maintained 35,000 feet in the cockpit, so that was okay.

The APU starts, both pressures came up to 4,000 and immediately came on back to; 3,200 on No. 1 and 3,400 on No. 2 hydraulic pressures. SAS checks went good. I did it on 4-4-8, and then reset 4-4-6 for the flight. We got an 1,800 psi pressure on the X-15 oxygen. I guess you got that when I repeated it? Pressurized the tanks, the prime, that was fine. Got the ready light. Jettison went off well. Radio checks went off well. Radio operated fine during the entire flight, and then somewhere around two minutes Russ indicated that the only thing that I could count on was stable platform attitude. Was a little better than that, as it came out. I will talk about that in a minute. Then at 50 seconds prior to launch, I went ahead and took over the time, ran on down, and I would guess I was only a couple of seconds off on the launch, but everything was good there. The manifold pressures came up steady just shy of 400 at pump idle, second-stage chamber pressure came up, was real fine. Then I went ahead and launched myself, and I was on the side stick and I was impressed because I got a pretty good roll off as I came off the hooks. Maybe chase can verify; do we have any of the chase pilots around? Joe, did you notice my roll off? (Uh, huh.) Didn't have any problem stopping, but it seemed as if the roll off was much more equivalent to what it had been in some of the earlier flights.

Question: Was it a right roll off as in previous flights?

White: The right roll off, yes.

Okay, there was no problem, however, and we went ahead and stroked the throttle right on up in one motion to 100%, and I got thrust. She quit; the valve malfunctioned, the light came on; I shut it off; hit the reset and hit the prime switch; and looked at things, and the igniter ready light did not come, so I waited a few seconds for this and I went back and hit the reset again; and when I hit the prime switch and held it there, the igniter ready light came on. I went back up with the throttle and delayed slightly and went up to about 75% thrust and I felt a good shove come in, then I pushed it on up. I went to 10° a and rotated here. I didn't catch the altitude. I wasn't paying any attention to the altimeter after the launch. I got to about 2.2 or 2.3g during the rotation when we got down to the lower altitudes and back on up. I figured as long as we didn't get to 3 or 3.5g we didn't have any problem; we weren't down where we had to worry about running into some pretty high q.

Somewhere in this sequence, I reset the clock and I started getting callouts from Neil, and his times were running 8 or 9 seconds behind what I was showing on the clock, so when I came up to 37 seconds on my clock, of course he was quite a bit behind me, he hadn't quite reached 30 seconds yet, and I went ahead at 37 seconds on my clock and pushed over and I got the indication that I was going to round out low. This indicated to me that perhaps the timing was better in his count. We were right on the second from what he was reading. To compensate for this then, I backed off on 0° angle of attack so I could get back a little bit of the altitude I think I would lose by rounding out low. Then I took the cue on his time and I went over to the inertial velocity indicator, and it seemed to be clicking off just about what I had expected it to,. compared to the time, and he went 65, 66, 67 seconds, then I made the throttle motion to shutoff, and the inertial velocity indicator indicated 4,600 feet/sec.

Immediately upon thrust termination, I got the pitch light blinking at me. I wasn't impressed with any transients in aircraft motions that would upset me, so that whatever it was, the amplitude was apparently low enough and the rate high enough to trigger this thing off. I was down at zero g so I ,just reached over, reset the pitch SAS immediately, at least that was without any problem at all, and went ahead and did a rudder pulse, which damped very rapidly, a pitch pulse, which damped out in a couple of cycles, and immediately upon the pitch damping I was back level, so I pulled on up pretty rapidly to 15° ac. At 15° a, there were a series of maneuvers scheduled, but the airplane wallowed quite a bit up here, and this is the way it continued. She just continued to oscillate in sideslip. The period was down low enough that it wasn't too exciting, but it just kept wandering back and forth with just a little bit of roll associated with it. The roll wasn't too much, but it was there. Obviously, any attempt to go ahead and upset the airplane and let go the control stick was just gone. It wasn't there, it was just a matter of trying to keep up flying this thing and I did this, attempting to remain at an elevated angle of attack so we could get something out of that. Then, as a matter of fact, part way through this cycle, I started to get over to flying ~ but it wasn't this bad; but I wanted to get over and start flying the ,B technique to chase this thing down and zero out the excursion in sideslip. It wasn't quite this bad, but it was pretty poor. You had to hang on to the control and work with the damn thing to keep up with it.

Very shortly after I played around here, I got the speed brakes open, and got a trim change which pitched me down, and I forced the airplane back up to the 15° a again. The airplane responses and characteristics were just about identical to what they were with the speed brakes closed. During this time, I noticed that the inertial height indicated --- about at the top of the trajectory, in fact, before I started on down,--- 130.000 feet. That indicated that point at the top. Then the next thing that I was aware of was a call from Jack that I was coming back through 100,000 feet, so I eased off on angle of attack and started down at an indicated velocity of about 2,800 ft/sec. Jack indicated speed brakes, and I went ahead and closed them at 2,800. ft/sec on the indicator. Very shortly after that, I was back to 70,000 feet; the airplane stability did improve as I came lower, and, of course, as I got her off the high angle of attack, flying between 8 and 10°. Then I started the turn, I guess I pulled about 10° angle of attack, holding the turn, and when you said, "Bring it on around," I was holding 2g at that angle of attack. I could see the lake out there. I had plenty of energy, and plenty of altitude, and there was no particular problem as far as I was concerned from the time we started the turn. It looked like I could negotiate this very easily. Then we got on around, and I waited until I got subsonic and by this time I transferred over to the center stick and was looking at the pressure instrument maintaining about 250 or 260 knots. When I got down to less than Mach 1, I went ahead and jettisoned. Got the indication in the cockpit. I never did hear anybody call it on chase. I did get the indication in the cockpit that I was jettisoned.

Thanks for the call on saving the source pressure gas, because it would have bled off if I didn't catch it. Then I used the No. 2 BCS system and cycled it in pitch, yaw, and roll. I couldn't get any indication that the BCS was doing anything to me in a left roll when I tried to roll left. There was a little bump in a right roll. I did see it pitch as it passed over the canopy, and I got a little indication in pitch both ways, and in yaw also. We got the BCS off and went around and flew the landing pattern, came in and landed without any problem at all. Despite the high winds out there, there wasn't any turbulence or anything that gave me a problem. I don't know how it was with you guys flying the airplanes making your approaches for landing, but sometimes you seem to run into some pretty good turbulence, but I didn't have any problem at all flying the airplane and landing. I touched down on the lake bed, which seemed to be a fairly good touchdown, and the nose came down with what seemed to be a hell of a good jolt. I understand it was a very hard part of the lakebed. Maybe this hard surface being as unyielding as some of the other places would seem to attribute to this. In the roll out, I pulled the stick back and threw It over to the left side, and continued to deviate in a right-hand turn, but it continued to go, I couldn't keep the airplane straight. I tried to use the directional (right rudder) control as well as the lateral control and I couldn't hold it straight. It continued off very slightly.

During the flight, after shutdown, some of the noises that I heard before were apparent again, some good thumps and bangs. The magnitude of these sounds were not as high as I had heard them in the past; nevertheless, they were there. They didn't occur, as I recall, till after shutdown; and until I elevated the angle of attack. Through the zero lift part of the trajectory it wasn't there. Then, as soon as I elevated angle of attack, came the bang and the thumps, and then I was impressed too at various times by slight vibration in the airplane. I don't know where this came from. The level of the vibration was -- the magnitude was low, the frequency of any of these vibrations was, I would guess, quite a bit less than what Joe had commented on in his last flight. They were not such as to give me any problems as far as control was concerned or feedback in the side stick. I used the side stick throughout the flight until I got down somewhere in the traffic pattern and then I started using the center stick .

In addition, after burnout, while I was still at high altitude, perhaps a minute after, I believe it is, the suit started to inflate. I looked at the cockpit altimeter, and the highest I indicated and held there was about 46,000 feet. This --compared to what I felt in the suit to be about a pound, what we get at 45,000 feet prior to launch -- insured that these things are compatible, namely pressure altitude at 46,000 feet and about 1 psi in the suit.

Just prior to transitioning back to the center stick --I was glad to do it -- I felt a little bit tired, perhaps because I was working quite a bit anyway jiggling this stick around, and it was just nice to get back to the center stick, although as far as flying the airplane, controlling it, the position of the side stick, this is fine as far as I'm concerned. With good flying qualities in the airplane, there is no problem using the side stick to control it. You can do exactly what you want to.

In trying to keep up with the excursions in sideslip, I think that I would have done exactly the same using the center stick as I did with the side stick. I don't think the control really had any influence. It is a matter of using the control as necessary to try and keep up with the wallowing in the airplane.

One other point. Again during the high-altitude portion of the flight, I did detect a little bit of this wisping smoke in the cockpit. Now this was far less than what it was last time, but it was enough that I did detect one or two very small wisps. It was there, I assure you, but not very much. It was during the high-altitude portion of the flight. It was after engine shutdown and pitch damper malfunction occurred at high altitude. Colonel Rowen can tell you exactly from his records. He has got the information up there, and he can pin point it exactly. Yeh, I don't know how rapidly the cockpit altitude increased, but apparently I didn't start to become aware of it until I was up near maximum altitude. This is rather difficult unless you are sitting there waiting for it to inflate.

Question:

White: The SAS popped off, and that was reset almost as quickly as it tripped. Immediately after pitch malfunction is when there was smoke in the cockpit. After SAS popped off, it was reset, and that is about the time the smoke in the cockpit was showing. The acceleration was about 3g during the flight.

A comment about the configuration in the cockpit. Using a 28-foot chute pack under it, and as far as I am concerned I would use it again. The headrest today, as compared to yesterday, is far superior; and I think that if anybody was flying it now -- (let's pay attention to this; I think we let this go by the boards before) if I had flown this same flight yesterday, it would have been just lousy, really, because my head was back at an angle where it would have been miserable.

I don't know what the g level was in the cockpit, but it was quite comfortable during acceleration. I was sitting in a good position. My head was upright compared with the torso. I had a good clear view of everything in the cockpit. Control of the airplane was no problem. The g force was such that we could have gone on a minute and this wouldn't have disturbed me at all.

Question:

White: Okay, the pad on top. Apparently this is all right, It seemed as though I was a little bit higher in the cockpit this time, this surprised me. I had been before. My eye level seemed to be just a little bit higher than it had been in the past and I seemed to get just a little bit of rubbing on each side of the helmet against the canopy. Just a little bit, and you can notice this particularly when you get a pound of pressure in the suit, pushed up a little bit and you can just rub back and forth and you can feel the helmet rubbing and it feels as though it is rubbing on each side.

Question:

White: Yeh, that is good. I was looking straight ahead where I should be. As far as the longitudinal g is concerned, this g level is no problem. Let's see what it is like now going up to 4. I remember 4g from the centrifuge program. This is kind of impressive sitting there for 88 seconds where you can feel a pretty good weight on your chest, but at 3g --

Question: Did you say something about the pad behind the right elbow on the sidearm control?

White: Oh yeh, you could increase the pad behind the right elbow. I like to have a little less there. There wasn't too much room and we ought to take into consideration the possibility of suit inflation and I think that this particular area right here is not going to offer us any problem when we are under g forces in a couple of axes, but the arm rest now, the side piece on the arm rest seems quite a bit farther away. It would be nice if it would be right up against that arm rest while you are in position holding the side stick. Now this, of course, could be quite a bit bigger problem. Something we can look into . This is just an impression I had. Yeh, this is very noticeable, particularly when you use side stick.

Question: What about side-stick position, Bob?

White: That was satisfactory. I suppose you, somebody would even like it even further forward but no, I am satisfied where it is for my particular configuration in this cockpit.

Question: Do you use the head bumper, Bob?

White: I did not use the head bumper, no, definitely not.

Question: Regarding the low fuel tank pressure before launch, what happened on pressurization?

White: No, it was higher than this. It dropped down to, I was watching this, it dropped down to about 41, and I had no sooner got the words out of my mouth, and she popped back up to about 43 or 44 . Yeh, that is about, right.

Question: Did you start pushover about 30° ~ ?

White: No, I got up to 30° ~ and I pushed off on angle of attack and held this for a few seconds before I pushed over.

Question: What about the ball nose? Did the a and ~ needles vibrate ?

White: No, they looked real good. They looked real good. The needles weren't vibrating at all and they were doing just exactly what I would expect them to do. They were following the airplane motions very well and made control inputs to try and stop it. It did exactly what you would expect it to do. I was pleased. No problem there.

Question: Did you turn on pulse and turn on cameras, the bug eye camera?

White: I turned it on I forget now where it went and I put it in the other position, is that what you find?

Question: Bob, did you get damping from the first pulse that you did after burnout at low angle of attack?

White: No, the first pulse is a rudder pulse and the damping was real good.

Question:

White: Right, and then the next is the pitch pulse which damped in just a couple of cycles. There was no problem at all there. It damped out and that was it. At the high angle of attack it was very sloppy. I'll argue with them on that too.

I'd like to make another comment. Using the side stick, of course, we select the normal trim position so that we can trim on the side stick in the beginning, that's the way I did it today. Now this wheel rotates very freely. I'm not sure whether or not putting more friction in there will help, but as you are banging around in this cockpit it seems as if it is very easy to hit this wheel and get it off trim. Now, Chase 1, I didn't solicit your comments, but they were real good. You kept calling the trim position to me, particularly when I'd wiggle the controls and so forth, you'd keep verifying that the stabilizer was in the right trim position, so this is something we might include in the chase, that, right up to the launch point to keep his eye on that, and then the pilot too is going to have to be particularly aware of it because it is real easy to move that wheel and get it out of trim. Of course, this would probably be a real problem at launch. Becoming aware of this, I paid attention to this a number of times, because just banging around in that cockpit I hit it and got it out of trim several times. As I say, I don't know whether increasing the friction on that wheel is the answer or not. I think we are going to have to be real alert to the -- that's right, and, of course, as I say, this could be bad because of the -- what might happen at launch.

Major Robert M. White

USAF