Two-Axis, Fluidically Controlled Thrust Vector Control System for an Ejection Seat.
HONEYWELL SYSTEMS AND RESEARCH CENTER MINNEAPOLIS MN
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A two-axis, hydrofluidic, thrust vector control TVC system was designed to stabilize an ejection seat during the critical rocket burn portion of the trajectory which should reduce the g loads on the crewmember and result in higher trajectories. The dynamic performance of a seat with a fluidic TVC system was analytically evaluated against established ejection seat requirements and physiological limits. This analysis showed that pitch rates were reduced by 60 percent and yaw rates by 90 percent when compared with a seat with no stabilizing system. Breadboard hardware was fabricated and tested with the components meeting requirements. A prototype integrated fluidic circuit and a moveable nozzle was then designed, fabricated and tested. The prototype system did not meet all the requirements due to a null bias instability in the fluidic amplifier which was caused by a nozzle asymmetry in the fluidic amplifier mold. The FTVC System included a vortex rate sensor, fluidic lag-lead compensator, and a four-stage fluidic servovalve. These components will use hot gas pressurized oil to drive a hydrostatically supported, piston actuated ball and socket nozzle with 20 deg of deflection of a 3500 lb thrust rocket. Initial nozzle breakaway friction was 170 in-lb. Operating stiction was 135 in-lb and running friction was 80 in-lb.