The Goshawk was developed from the Kestrel IV prototype engine, to use evaporative (also known as "steam") cooling. Rather than keep the cooling liquid below its boiling point in the cooling system, the coolant was allowed to boil; boiling taking more heat from the engine and less coolant was needed. However instead of a radiator to take the heat from the coolant, a condensor was required to turn the vapour back to liquid. These had to be much larger than radiators and added drag to the aircraft design.
Twenty engines were built and they flew only in prototypes as a few manufacturer's private ventures and "one offs". Powers for individual installations are quoted between 650 and . Problems with coolant leaks, coolant pumping and the realisation that large wing mounted... Read More