Low Temperature Evaluation of Advanced Technology Hydraulic System (8,000 psi).
Final rept. Sep 82-Apr 83,
VOUGHT CORP DALLAS TX
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Tests were conducted at temperatures from - 40 F to 120 F on two simulated aircraft flight control hydraulic circuits. One of the circuits used an A-7 aileron flight control actuator designed for 3000 psi operating pressure with 38 and 14 inch diameter tubing. The other circuit used an actuator designed for 8000 psi operation with 14 and 316 inch diameter tubing. Both actuators were designed for the same frequency response, rate and thrust requirements. MIL-H-83282 fluid was used for all tests. Frequency response and zero load rate tests at varying temperatures on the two circuits established the minimum temperatures at which performance requirements were met. Time versus temperature data from A-7D Category II Tests was used in heat transfer calculations to provide a comparison of warm up times for aircraft systems using 3000 or 8000 psi. Results of all tests and analysis indicate that there is no essential difference in warm up time for systems operating at 3000 or 8000 psi.