Goran Popovic

O2 injection was tested on PR Spitfire "specials" made by Heston, but it was quite dangerous and difficult and wasnt used in service. Nitrous oxide was actually used in service on the Merlin by a special group of Mosquitos in 1944, including night fighters. All these were oxidising agents, for high altitude use, there was usually no point using water injection on the Merlin, as this is only really useful for increasing output beyond max peak power at low to medium altitudes (it cant do much beyond rated height as it doesn't act as an oxidiser because the oxygen is in stable bound form and doesnt dissasociate except under very extreme conditions). Since the Merlin was usually so highly developed, it was running very close to its mechanical limit in the war, use of water injection on it was limited to some special trials for chasing V1 flying bombs, where the drastically reduced engine life could be permitted. Less well designed engines, which could not GET near their mechanical limit because of bad cooling, or terrible combustion, conversly - benefitted greatly from water injection due to the immense cooling effects.