Pilot -- Major Robert A. Rushworth
Resume of Flight Request
2. Maintain climb at 10°a to q = 30°.
3. Maintain climb at 30° q, pushing over to zero g and extending speed brakes at 83 seconds.
4. After coming level, trim to 1.5g, perform wings level side-slip with sharp rudder release.
5. Shutdown engine at 120 seconds, set SAS 8-0-4.
6. V = 3,700 fps, perform rudder pulse at 5° a.
7. V = 3,500 fps, rotate to 25° dh (max. trim) and perform rudder pulse. Allow 3 cycles for damping; followed by 30° aileron roll.
8. V = 2,700 fps, pushdown to 10° a and perform rudder pulse while decelerating to V = 2,200 fps. Stabilize briefly between pulses and evaluate handling characteristics.
9. V = 2,200 fps, close speed brakes and perform rudder pulse.
10. Transfer to sidestick and continue rudder pulses.
11. Subsonic, turn SAS 8-0-0 and perform rudder pulses.
12. Landing, SAS 6-4-8.
P.C. The launch was good except for bringing the throttle back to 50% and achieving 10° a. It took longer than anticipated and I think the difference is due to the technique used. For the simulator, as soon as the airplane was launched I started trimming and in the airplane, after launch, I started pulling force and then trimming. The rotation was satisfactory and somewhere between 40 and 50 seconds I started the pushover to zero g. The pushover was started early as I didn't believe the angle of attack was accurate and that I was climbing steeper than 10° allowed. The pushover altitude was about as scheduled.
I did not have the clock for shutdown so waited for the 120 second ground callout for the shutdown que. The velocity was close to 4,000 ft/sec at shutdown. One check during the acceleration revealed 3,400 fps indicated for 3,200 ft/sec ground callout. The speed was about 3,400 ft/sec when I went into the left sideslip. I did not get a full left rudder deflection. I started in with the rudder deflection and the airplane immediately rolled to the right. I stopped the roll with a left stick (center stick) deflection and then continued to feed in more rudder. Finally the bank angle was held steady at a 20° bank angle. I don't know the final rudder deflection. At the beginning, the airplane did not move at all and I believe that 1/4 rudder deflection was put in, and all of a sudden the airplane rolled. I brought the stick over and the motion stopped. I put in a bit more rudder, moved the stick left and the airplane became steady -- steadier than I had expected from the simulator. On the release, the airplane rolled. It made a couple of oscillations and I over corrected in trying to steady the airplane. It was easier to control than what I had expected from the simulator.
Discussion pertaining to Sequence of Events
After I performed one sideslip, shutdown occurred, roll damper off and then pullup to a = 11°. I can't remember where the damper was shut off. It was off as I had to turn it back on at 2,200 ft/sec. As stated, I do not remember turning the damper off and there is a possibility is did trip out;
During the period of flight at high angle of attack, there was some mild buffet and I did not pullup into it. The buffet occurred at about 15 a and stopped at 11° a. At about 2,000 ft/sec I received a radio call to retract speed brakes and did so. I then transferred to the side stick and did feel it out a little, however, not enough to comment on. I do remember the trim change while decelerating from Mach 2 to Mach 1, because it brought the airplane out of a dive position to level flight. I had about 300 knots airspeed and maintained this while waiting for the chase plane to catch up. I called when I was subsonic and opened the speed brakes. I then used some speed brake (approx. 10°) from the 270° point to the 180° point and through to final approach. I had the brakes open as low as 5,000 feet as I could see I was going to be long at landing.
In going back at about 50,000 feet, I had the sensation of some fuel sloshing -- I associated the motions with the fuel because I could hear something. I was steady on the stick and did not et the impression that it was a damper pulse or control induced motion. The speed brakes were in and this was about the time I went back to the center stick.
I. Launch (t = 0 - 10 sec)
P.C. The launch was smoother and similar to previous flights. One to 1 1/2 inches left center stick deflection was held, however the airplane still rolled off » 5° to the right when it cleared the B-52. The airplane then righted itself. Apparently I was so conscious of it that I just watched it all the way through, even before I thought about lighting the engine.
B. Please describe any system failures, and the resultant airplane control task at launch, or after engine start.
P.C. There were no system failures except for the clock. The control task was as expected except for trouble getting up to 10° a.
C. Please describe any distracting factors present during this period.
P.C. There were no distracting factors present.
P.C. I used a different technique than on simulator. I pulled force and then trimmed to the angle of attack. At the given q, I had the feeling of being at a steeper angle and started the pushover earlier.
B. Please estimate airplane controllability limits during the climb.
P.C. Simulator: a » ±1° b = ±1° q = ± 1°, f = ± 10°
Airplane: a = 10° ·1/2°, b = ? ± ?, q = flight plan.
f = 0°, heading = 0°. I don't recall getting a full 30° q.
c. Please describe any SAS residual motion feedback to the control stick.
P.C. I did not feel any SAS feedback.
D. Please compare airplane controllability during climb with your previous flights (ventral on).
P.C. The roll mode appeared to be less sensitive than on previous flights.
E. Please rate over all climb task.
P.C. Simulator: Pitch 2 1/2, Roll 4, Yaw 3
Airplane: Pitch 4, Roll 3, Yaw 3. At one g or positive, I rated pitch low because of trouble pulling her nose up. (The control task of achieving climb attitude.)
P.C. The airplane matched the simulator very well during this time period. The yaw damping was poor - approximately 50% less than for the rest of the flight. At one time, the sideslip needle was deflected to 3° during the pushover. The period was about 2 seconds and the damping low.
B. Please describe corrective control to retrim airplane with speed brakes extended.
P.C. Simulator: Less than 1° nose down required, however airspeed is also changing during this period.
Airplane: No answer.
C. At zero g, did any directional motion result from lateral control inputs? If affirmative, please describe, noting amount of lateral control applied: qmax, bmax, phasing f~±, and the level of directional damping.
P.C. Roll control inputs were not observed but directional damping was poor and closely matched the simulator.
D. Please rate pilot control task during acceleration at zero g.
P.C. Simulator: Pitch 2 1/2, roll 4, yaw 3.
Airplane: Pitch 2 1/2, roll 3, yaw 5.
The yaw rating is taken from the b needle.
E. At 1.0g, please describe airplane response to sideslip maneuver, noting amount and direction of aileron control applied to keep wings level and an estimate of the directional static stability.
P.C. Simulator: Left pedal for right sideslip and left stick were used to keep wings level. Approximately 40% stick deflection was needed to keep wings level. Retracting speed brake causes b pr 15° and reverses the aileron required for wings level.
Airplane: Approximately one-half left stick deflection (stick against leg) was used for a left rudder pedal displacement.
F. Please rate airplane controllability in sideslip.
P.C. Simulator: Pitch 2 1/2, roll 4, yaw 2+.
Airplane: Pitch 2-3, roll 3, yaw 4.
G. Following sideslip, please describe instrument panel scanning sequence during final acceleration to Vmax. Compare cockpit readings with ground control callouts.
P.C. The clock did not work. The cockpit altitude indicator was within 2,000 feet of ground callout at all times. Vmax at shutdown was 3,900 +ft/sec. Shutdown was performed on time and according to ground callout.
H. Was sufficient time available to anticipate engine shutdown point? What cue was used?
P.C. Simulator: Sufficient time was available and time (clock) was the primary cue.
Airplane: Sufficient time was available. When I first looked at the inertial speed I expected to see 3,000 ft/sec and actually saw 3,400. The ground controller had just called 3,100 or 3,200. The next time I checked the speed was at the controller countdown for the shutdown and the speed was again higher than I expected. I believe this extra speed is due to the engine being run at 75% thrust for part of the time.
I. Were any distracting factors present?
P.C. There were no distracting factors.
J. Vmax was 3,900 fps.
K. Please describe any system failures, and resultant airplane control task at engine shutdown.
P.C. There were no system failures.
P.C. Simulator: The damping was from 10 to 20%. Bank angles less than 90° develop during the oscillation following the pulse. Lateral corrective control inputs applied.
Airplane: The damping was fair and the lateral control was good, I did not perform the rudder pulse at 5°a.
B. Please rate airplane controllability at 5°a.
P.C. Simulator: Pitch 3, roll 5, Yaw 4.
Airplane: Did not perform.
C. Following pullup to 25° dh (max. trim), please estimate longitudinal damping and static longitudinal stability level.
P.C. Simulator: Pitch rating 4. There is no overshoot if either trim or force is held.
Airplane: 11°a was achieved. I did not have any trouble with the longitudinal damping.
D. Following rudder pulse at 12°a, please estimate directional damping and describe corrective control required to retrim airplane.
P.C. Simulator: Damping was from 10 to 20% and lateral control was required.
Airplane: I did not use corrective control after performing the pulse, however, I did get a little roll off and may have moved the stick a small amount. I did not take my hands off the stick.
E. Please describe airplane response to roll control input, noting fmax, bmax, level of lateral-directional damping, phase q~b and corrective control required to retrim airplane. Bank angle would be held ±10° (simulator).
P.C. I did not get over 30° in bank angle. I was short on time.
F. Please rate airplane controllability at 10° a.
P.C. Simulator: Pitch 4, roll 5, yaw 5.
Airplane: Pitch 3/ 1/2, roll 3, yaw 4.
P.C. Simulator: 1°-2° nose up trim required. Airspeed change masks trim change.
Airplane: There was no change. All forces were trimmed out as I brought the speed brakes in while decelerating.
B. Please rate airplane controllability using side stick.
P.C. Simulator: Pitch 4, roll 4, yaw 4.
Airplane: I did not spend enough time on the side stick to make a proper evaluation.
C. Did you notice any particular roll sensitivity when you turned the dampers back on?
P.C. No, the only comment I have is, with the damper on, I was not over controlling.
P.C. I would like to comment on preparing the airplane for flight. Every time I reach up to close the canopy my arm scrapes across the trim button and every time I get a trim change on the motor however, there are no hydraulics on at this time.
Question about roll control in the traffic pattern.
P.C. Roll control matched the simulator, and took large stick displacements to produce the desired bank angles.
P.C. I was hoping to repeat the procedure of my last flight which was successful. I intended to actuate the flaps and let the associated time change produce the flare. This procedure was used and I trimmed a little forward stick at the end of the flare, put the gear down, started the stick moving back and landed. The cues used were a combination of altitude and aim point.
B. What was speed and altitude at flare initiation point?
P.C. Vi was 320 knots on base leg. I used some speed brake at 6,000 feet. I was trying to hold Vi = 300 knots and maintained 300 to 310 all the way around the pattern. I had 300 knots at about 4,000 feet for flare initiation.
C. Where was flap actuated relative to flare initiation point?
P.C. Flap actuation came soon after flare initiation. I waited until the airspeed was below 300 knots before I started them down.
D. Was an aiming point used prior to the flare?
P.C. I was aiming just short of the one-mile marker.
E. Was a spot landing attempted? How far from planned point was touchdown?
P.C. I shot for a spot landing and, overshot by as much as 1,000 feet.
F. Were aero controls used successfully for runout control?
P.C. After the nose came down I used full back stick. The airplane did drift. I put in some control that was ineffective.
G. You came over the base high. Did you have any difficulty with visibility?
P.C. I had good visibility and was able to see the base and lake clearly.
H. Did you notice any ground effects?
P.C. In comparison to the F-104, at 200 knots in the F-104 you set a sinking feeling and start to go down. The X-15 does not give this feeling. At 200 knots the X-15 is still flying.
B. Other than kinesthetic cues, please note airplane control characteristics which were not encountered in the simulators. (Fixed base and variable stability F-100).
P.C. I would prefer to answer the question later after I fly the F-100 airplane.
C. How effective was the ground control operation in executing the flight mission?
P.C. The ground control looked good all the way. The actual flight seemed shorter in time than a simulator run.
D. Were X-15 flight characteristics experienced in this flight comparable with other aircraft you have flown?
P.C. The F-106 airplane flying at 25,000 to 30,000 feet at subsonic Mach number.