CORRELATION OF ANALOG SOLUTIONS WITH EXPERIMENTAL SEA-LEVEL TRANSIENT DATA FOR CONTROLLED TURBINE-PROPELLER ENGINE, INCLUDING ANALOG RESULTS AT ALTITUDES

摘要

A satisfactory correlation was obtained between experimental sea-level transient data at constant flight speed and solutions from the analog representation. The analog representation is accomplished by transfer functions that were formed from a frequency-response analysis of the' experimental transient data as obtained from the controlled engine. This analog representation was then used to compute system response at altitude.nThe engine-control system with an underdamped sea-level turbine-speed response and fixed-control constants resulted "in an oscillatory system at 35,000 feet. Variation of control constants to maintain sea-level turbine-speed response at all altitudes resulted in large blade-angle initial overshoot at 35,000 feet. This large blade-angle overshoot may result in over torque at 35,000 feet if the sea-level overshoot approaches maximum allowable torque. Variation of control constants to maintain system loop gain and ratio of engine time constant to control time constant at sea-level values resulted in a similar initial turbine speed and blade-angle overshoots at 35,000 feet, but in an increase in the time required for turbine speed to first reach its final-value.