INTRODUCT ION Conventional internal conbustion a i r c r a f t engines require the same basic conditions for starting in cold weather as they do in warn weather. These are: (1) The engine must be cranked a t a reasonable speed. ( 2 ) A combustible mixture must be delivered t o the cylinders. (3) An ignition spark must be supplied which is capable of igniting t'ne charge a t the proper t i m e . (4) The fits and olearanoes of mating parts in the engine m u s t be such that normal Sunctions occur a t a l l temperatures. (5) The engine must receive a usable lubricant. (6) The engine must develop s u f f i c i e n t power t o overcome its own f r i c t i o n and accelerate itself t o the desired operating speed.