| 摘要 |
1,097,924. Controlling variable-pitch propellers. J. SZYDLOWSKI. April 14, 1965 [April 21, 1964], No. 15918/65. Heading B7V. [Also in Division F1] Apparatus for controlling a gasturbine engine 2, Fig. 1, which is coupled to a variable-pitch screwpropeller 3 in an aircraft, comprises a valve 113 that controls the flow of fuel through a pipe 9 to the engine and is operated by a device 110 in accordance with the difference between pressures P 1 , P 2 at either end of an air compressor 1 for the engine, the pressure P 2 being communicated to the device through a pipe 112 that includes branches 320, 321 controlled by valves 322, 325 whereby air can be released to reduce the pressure difference at said device when the rate of flow of fuel to the engine is either at, or greater than, a maximum permissible value or less than a value approaching the maximum permissible one e.g. 95% of the maximum permissible value, when the rate of flow is increasing, whereby the power-output of the engine is reduced. When the maximum permissible rate of flow of fuel is approached, an electric motor 4 for changing the pitch of the propeller 3 is de-energized by a control network, Fig. 4 (not shown), to prevent further coarsening of the pitch; and, when the rate of flow reaches the maximum permissible value, the motor is energized so as to effect a reduction of the pitch. The valve 325 is actuated by a solenoid 326 that is energized to open the valve when one or other of a pair of contacts 138, 139, Fig. 2, is engaged by a movable contact 136 in a comparator 114 as a consequence of changes in pressures p 1c , p 2c in the pipe 9 on either side of the valve 113 due to changes in the rate of flow of fuel. The valve 322 is manually controlled and can be directly operated by the pilot of the aircraft. The apparatus may be used to control a gas-turbine engine that is coupled to a variablepitch screw-propeller in a water-borne craft, and the electric motor 4 by hydraulic means for changing the pitch of the propeller. In many respects the apparatus in similar to that disclosed in Specification 922,255. |
