Subject: Initial Summary of X-15A-2 flight 2-35-60
The X-15A-2 performance did not match that of the simulator, precisely, during the powered climbout. The pilot followed the planned profile accurately, however he reached the shutdown point (i.e. 4500 fps) early, approximately 76 seconds after engine light (planned time was 80 sec). The actual measured velocity by radar indicates that the shutdown velocity was 4400 fps. This could possibly account for no more than 1 sec of the short burn time.
It was decided, by the flight planner, to investigate the possibility of the thrust level during the flight being higher than previously published. It was discovered that a thrust of 60,000# enabled the simulator to match precisely the flight performance.
The flight operations engineer responsible for the engine operation was informed of this discovery, and subsequently revised his engine performance to 60,000#. This change was not influenced by the simulator results, but rather was based on a review of the engine performance parameters.
B. Stability and Control
The rotation characteristics previously experienced with the X-15A-2 did not materialize on this flight. The pilot noted normal rotation characteristics to q = 20°.
Roll off problems previously noted, again did not materialize during this flight. Twice the pilot attempted to induce the roll off without success.
Handling throughout the pattern during landing phase was normal and satisfactory.
C. Landing Loads
The landing loads for this flight were low in comparison to previous flights. The actual measured loads were recorded on the Parsons tape. A record of the results is enclosed.
D. Mission Objectives
The Mission objectives were:
1. Landing Gear Checkout
2. Stability and Control Studies
3. Star Tracker
Checkout
The left main gear was also deformed, but not to the extent of the right gear. Studies are now under way by both FRC and NAA to determine the cause of the deformation and the required fix.
2. Stability and control studies were considered successful in that the pilot performed all required pulses using a stick free response technique.
3. The Star Tracker experiment was a failure in that the operation of the cameras could not be checked. A 1-amp fuse was placed in a 3-amp circuit by the contractor, thus resulting in an electrical failure upon experiment activation.