Ram-air cooling systems for aircraft generators

WHEN AIR is taken aboard an aircraft in flight, it undergoes an increase in pressure which is called the ¿ram effect,¿ and a cooling system which uses such air is called a ram-air cooling system. Up to the present, almost all systems for cooling aircraft generators have been of the ram-air type and, in addition, the simplest subdivision of the type, the so-called blast-cooling system. In this system, the generator is in effect simply hung overboard, and cooled by the stream of air forced through it by ram pressure. (In practice, the generator is mounted inside the aircraft diffuser.)