Preliminary Analysis of Wind Tunnel Test of a 1/2Scale Model of an Ejecting Crewman and Ejection Seat.

摘要

Doubts were raised as to the integrity of the rest of the structure when the neck member of a model crewman failed during tunnel measurements of the limb forces during ejection. The accuracy of the load estimates used in the pretest stress analysis clearly needed to be checked. Meanwhile, testing was resumed at restricted pressure values with a non-load-measuring replacement for the neck member. From a sampling of the test data, the distribution of bending and torsional moments along the limbs is clearly revealed and, with its variation with attitude and Mach number, presents no great surprises. Values critical to the stress analysis confirm the estimated values. The neck pillar, designed by a subcontractor, had been designed for sensitivity in bending under the head loads without catering for torsion in the member if these load should in the event be appreciably offset from its axis. Although there is little confirmation of the magnitude of the head loads, there is some indication the offsets in excess of one inch in these loads are to be expected in the real situation, and that the resulting torsion was the cause of the failure. (Author)