The aeroplane launching catapult is a means whereby in a very short distance the speed of an aeroplane can be accelerated from rest to that at which it becomes air borne.

Fundamentally the aeroplane launching catapult comprises a carriage on which is mounted the aeroplane to be launched, a motive plant which causes the carriage to travel at an increasing speed along a prepared track or structure and a means of arresting the carriage after the aeroplane has attained the necessary flying speed.

In this paper the author does not propose to deal with any particular form or type of engine or fuel-injection system, but to discuss some of the problems which are encountered when engaged on the development of a high-speed compression-ignition engine.

The main problems to be solved consist in devising suitable means for utilising to the fullest possible extent the oxygen available within the cylinder and for avoiding the production of smoke and noise and, in so far as it is connected with combustion conditions, smell.