A very sophisticated conical intake was featured on the SR-71's Pratt & Whitney J58s that could move a conical spike fore and aft within the engine nacelle, preventing the shockwave formed on the spike from entering the engine and stalling the engine, while keeping it close enough to give good compression.
First run in 1951 the engine was flight tested during 1953 using an Avro Lancaster provided by Air Service Training, the engine being installed underneath in a nacelle faired-in to the Lancaster's bomb bay.
The various components of the modern active yaw systems vary depending on the design characteristics but all the active yaw systems include a means of rotatable connection between nacelle and tower (yaw bearing), a means of active variation of the rotor orientation (i.e. yaw drive), a means of restricting the rotation of the nacelle (yaw brake) and a control system which processes the signals from wind direction sensors (e.g. wind vanes) and gives the proper