Pilot: Capt. Charles E. Yeager

Time: 14 Minutes

9th Powered Flight

1. After normal pilot entry and the subsequent climb,

the X-1 was dropped from the B-29 at 20,000' and at

250 MPH IAS. This was slower than desired.

2. Immediately after drop, all four cylinders were

turned on in rapid sequence, their operation stabilizing

at the chamber and line pressures reported in the last

flight. The ensuing climb was made at .85-.88 Mach,

and, as usual, it was necessary to change the stabilizer

setting to 2 degrees nose down from its pre-drop setting

of 1 degree nose down. Two cylinders were turned off

between 35,000' and 40,000', but speed had increased to

.92 Mach, as the airplane was leveled off at 42,000'.

Incidentally, during the slight push-over at this

altitude, the lox line pressure dropped perhaps 40 psi

and the resultant rich mixture caused the chamber

pressures to decrease slightly. The effect was only

momentary, occurring at .6 G's, and all pressures

returned to normal at 1 G.

3. In anticipation of the decrease in elevator

effectiveness at speeds above .93 Mach, longitudinal

control by means of the stabilizer was tried during the

climb at .83, .88, and .92 Mach. The stabilizer was

moved in increments of 1/4 - 1/3 degree and proved to

be very effective; also, no change in effectiveness was

noticed at the different speeds.

4. At 42,000' in approximately level flight, a third

cylinder was turned on. Acceleration was rapid and

speed increased to .92 Mach. The needle of the

machmeter fluctuated at this reading momentarily,

then passed off the scale. Assuming that the off-scale

reading remained linear, it is estimated that 1.05

Mach was attained at this time. Approximately 30%

of fuel and lox remained when this speed was reached

and the motor was turned off.

5. While the usual light buffet and instability

characteristics were encountered in the .88-90 Mach

range and elevator effectiveness was very greatly

decreased at .94 Mach, stability about all three axes

was good as speed increased and elevator effectiveness

was regained above .97 Mach. As speed decreased after

turning off the motor, the various phenomena occurred

in reverse sequence at the usual speeds, and in

addition, a slight longitudinal porpoising was noticed

from .98-.96 Mach which (was) controllable by the

elevators alone. Incidentally, the stabilizer setting

was not changed from its 2 degrees nose down position

after trial at .92 Mach.

6. After jettisoning the remaining fuel and lox a 1 G

stall was performed at 45,000'. The flight was

concluded by the subsequent glide and a normal landing

on the lake bed.

CHARLES E. YEAGER

Capt., Air Corps