IN opening this subject, it is perhaps in order to point out that the term Supercharging is applied where we are concerned with restoration of sealevel power at altitude. The power of an aero engine varies in proportion to the air density. For every 100 h.p. available at sea level, only 70 are available at 10,000 ft. and only 49 at 20,000 ft. In the case of highflying aircraft, the engine thus spends most of its life developing only a fraction of its normal groundlevel power, and although this may be beneficial from a life point of view, it seriously limits the performance. It is the duty of a supercharger to restore ground level pressure in the induction system of the engines by means of an independent charging pump. This leads to a considerable increase in performance of the aircraft, and further it also materially assists the rate of climb.
Aircraft Engineering and Aerospace Technology – Emerald Publishing
Published: Aug 1, 1929