Flight 3-56-83 was flown on November 1, 1966, by William H. Dana for the purpose of obtaining data for: a) cockpit display evaluation, b) sky brightness (#19), c) optical background(#25), (d) micrometeorite collection (#13), e) tip pod accelerometer, f) horizontal tail loads, g) heat transfer panel checkout.

The maximum velocity attained was 5,500 fps (3,750 mph) and a Mach number of 5.08 at an altitude of 161,000 ft. The maximum altitude reached during the flight was 310,000 ft. The flight profile deviated 43,000 ft from the planned altitude. This was attributed to an approximate 2 second increase in burn time and a 3° excess in the planned pitch angle. The T/C commutator froze up and worked only intermittently during the flight.

Data were obtained as planned with the following exceptions: a) data on the micrometeorite collector were not obtained due to a malfunction of the collector sequencing motor. This will be repaired before the next flight of the experiment, b) the T/C commutator froze up due to cooling LN2 flowing over it. The hole outlets which directed this LN2 were filled to correct the condition.

Profile

The radar track and profile for this flight is shown in figure 1. Figure 2 is a time history of performance and stability parameters.

Launch was normal with engine ignition approximately 1.2 seconds later. The airplane was rotated to about 10° a and averaged 10.5° until q was reached. Planned a was 11° but q of 39° was reached 4 seconds early at 26 seconds. Due to a lack of sensitivity on the q vernier, q was increased to 42° without the pilot being able to detect the movement. q averaged 42° for the remainder of the boost.

A pitch pulse was performed at 57 seconds after launch (M » 3.1, h » 85K) for tail load data and a zero and calibrate was taken.

Sideslip excursions due to thrust misalignment reached maximums of +2.5° and -3.5°. Heading was not changed by these and the pilot indicated that the precision heading indicator was good.

The engine burned longer than anticipated and was shut down by the pilot, as planned at 5,400 fps. Tail-off carried the peak velocity to approximately 5,500 fps as compared to a predicted burnout velocity of 5,270 fps. The combination of approximately 280 fps and approximately 3° additional q account for the overshoot in altitude to 310K feet.

The pilot's checklist came free at shutdown and flooded the cockpit with loose pages, partially obstructing the pilot's view of the instrument panel. He pushed over to a = 0° as planned and continued momentarily to a = -8°. No adverse motions were noticed at the negative angles-of-attack.

The pilot used the precision attitude indicator over the top and was satisfied with the performance of the instrument. The inertials were indicating accurately over the top and continued to do so through the flight. The change from ball nose b to computed b showed about a 3-4° offset in computed b again this flight. Computed a looked good.

The pilot used a = 24 to 25° for entry as requested because of the increased altitude. Normal acceleration averaged 5g for 20 seconds and entry q was held down to about 1,050 psf.

Following the entry the pilot bounced to 80K as planned and performed another pitch pulse, zero and calibrate at about 329 seconds after launch. He attempted a tail load point in the vicinity of Cuddeback but discontinued the pullup at 5g. The a change was from 1.5 to 11.5° and back to 2° which should give a good data point.

The remainder of the flight was routine.

Optical background (#25)

The spectrometer functioned well during the flight. The experimental data were reviewed and signals were present on both channels. The data are being shipped to the experimenter for analysis. This is the last anticipated flight for this experiment.

Micrometeorite collection (#13)

During preflight checkout the experiment was run with a "dummy" collector box. At this time the experiment functioned properly, so the ''dummy'' was replaced with the flight collector box. After the flight, it was discovered that the collector had not sequenced through all six faces. At the postflight examination it was found that the sequencing motor failed due to a pair of over-torqued bolts. The exposed collector box was returned to the experimenter for examination and the bolt problem was corrected.

Air density (#12)

A preliminary review of the film showed that all four channels functioned as planned. This data will be sent to the experimenter and be reviewed and analyzed. The experiment was monitored for radio-active contamination after landing, and was found to be free of exterior a particles. This problem was one of major concern since the experiment contained a new Americium source.

Sky brightness (#19)

The experiment functioned properly and data were obtained. The data are being sent to Nortronics for closer inspection and analysis.

This was the third flight for this experiment and it is scheduled to fly on one more flight.
 
 
 
 

Horizontal tail loads

Strain gage data were obtained during the flight. However, the T/C readings from the horizontal tails were not recorded. The T/C commutator froze up and only worked intermittently through the flight. The thermal stresses were of concern since they are suspected of influencing the data acquired in the last flight. At this time the data have not been closely reviewed to determine if the data can be used.

Instrumentation discrepancies

0-21-36C - channels 14 and 27 only have only one calibrate deflection caused by a poor printed circuit card socket fit.

P-27-12 - MA 76 - MA 122 and Bi metal had slight shifts.

The T/C commutator froze up due to cooling gas. The orifices directly in line with the commutator were filled to correct the problem.

Operational discrepancies

The pitch angle preset was operating in a non-linear region, causing loss in sensitivity of the pitch vernier. The unit has been replaced for the next flight.
 
 
 
 

E. J. Adkins, Chief

X-15 Research Project Office