To-day all altitudes up to, and including, the stratosphere are within the scope of aviation. The engines must therefore be provided with highly developed superchargers so as to obtain high performance even at these altitudes. The single or multi-stage superchargers necessary to accomplish this become an integral part of the engine and exercise a distinct influence on its general construction.
In many types of engine the supercharger is built on to the accessory drive end, that is the rear of the engine, so that the supercharger shaft lies co-axially or parallel with the crankshaft.