Plane: X-15 #670 Carrier: B-52 #003 Takeoff: 0945

Flight: 1-22-37 Pilot: Capt. Allavie Launch: 1035

Pilot: Cdr. F. S. Petersen Co-Pilot: Capt. Kuyk Land: 1044

Date: 10 August 61 Launch Panel: Russell Total: :09

Chase #1: F-100 Major White

Chase #2: F-104 J. Walker

Chase #3: F-104 Capt. Rushworth

1. All servicing, taxi, take-off, and pre-launch phases were normal with the following exceptions:

(a) After a satisfactory suit inflation check at about 39,000 feet during climbout, the B-52 stable platform cooling was again turned on. The X-15 cabin altitude did not return to 35,000; rather, it stopped just above 36,000 feet with some slight suit inflation. The fact that the suit was slightly inflated was checked by turning the vent off. After going to X-15 cooling and pressurization, the cockpit altitude returned to 35,000 as it was prior to the suit inflation check.

(b) Both APU tanks upon being pressurized for BCS checks at 13 minutes before launch came rapidly up to 560 psi then immediately dropped to about 450 psi and recovered rapidly to a steady 560 psi.

(c) During ground taxi checks and during SAS monitor cutouts in the air before APU's were started, it was noted that when the roll channel cut out only the roll light would blink. On the X-15 simulator loss of the roll SAS channel also causes the yar channel light to come on.

2. The launch was somewhat disconcerting as several seconds elapsed after the auxiliary launch switch was operated before the drop occurred. Actually the pilot had decided that he would be unable to launch himself and he'd decided that the B-52 pilot would have to open the shackles by the auxiliary system when launch occurred.

3. Engine light was normal, smooth, rapid and as expected at the 75% détente with subsequent reduction to 50%. The roundup phase seemed to require more nose-up control than was anticipated. As a result of this and the rapid acceleration rate the pilot got behind the nose-down transonic trim change and averaged low on the desired angle of attack while establishing the desired climb attitude.

Pushover took place near the desired altitude and was initiated on a ground control callout at 58 seconds. At this point indicated inertial velocity was about 2000 fps vs. the 1800 fps expected from simulator runs. As the flight path became level inertial velocity was about 300 fps higher than expected. Shutdown was accomplished on ground callout at an indicated inertial velocity of 4100 fps with no shutdown transients. All systems appeared to operate normally during the powered portion of the flight. Longitudinal acceleration forces were light initially building up to moderate but certainly not debilitating values at pushover. At pushover the pilot had been holding his head forward about two inches against the forward head bumper. As forces were becoming noticeable the pilot relaxed against the head backrest with no noted vertigo effects. During the entire flight the center stick was used exclusively.

4. Immediately after shutdown the speed brakes were actuated full open and the roll and yaw SAS channels were turned off. While accomplishing these actions the pilot noted that some pressure existed in his pressure suit and it was further noted that cabin altitude had increased to 45,000 feet. Very soon after the roll and yaw SAS were turned off, a directional. oscillation began and appeared to build up to about 4-5° amplitude with the pilot attempting to make no control inputs. Bank angle oscillations were of about the same magnitude and caused no concern. Bank angle did tend to increase in a right wing down direction to 40° or 50°. This was corrected by small but conventional lateral control inputs. As inertial velocity decreased through 3000 fps the pilot became convinced that small control inputs induced by airplane motions through the pilot control loop were feeding the directional oscillations. The pilot removed his hand from the control stick and the next two or three cycles of the directional oscillation were noticeably damped. The pilot again took hold of the center stick and the directional oscillation increased in amplitude to about 5° amplitude. The roll and yaw dampers were turned on and the speed brakes closed as inertial velocity decreased to 2200 fps. At no time did the pilot attempt to increase the angle of attack above the trim value at engine shutdown which was about 6° The directional oscillation experienced was not as expected from simulator practice in that the X-15 simulator is quite steady at 5-6° angle of attack in this Mach number and dynamic pressure range. Further, oscillations characteristic of the simulator at higher angles or attack in this area have much greater roll amplitudes. The side forces exerted on the pilot were noticeable and were not smooth or sinusoidal in nature. The side loads seemed to change direction suddenly and maintained about the same level until the next reversal. It is felt that a pilot can safely use the angles of attack which existed during this oscillation while under the distracting influence of reentry and its associated accelerations.

5. A high speed brakes open approach was made from about 50,000 ft. to 20,000 ft. at the 180° position. The pattern was reasonably normal from the 90° position to touchdown. After touchdown at about 200 kts. the center stick was displaced full aft, the speed brakes were closed, and the flaps were raised.