water methanol
Water methanol is used but for a slightly different reason. I cubic centimetre of water in its liquid phase becomes 22.4 litres of gas (steam)! Ouch! That adds to the thrust in any engine be it the last models produced of R-R Merlin, DC-8's on a roll (That you Old Smokey?), the Harrier in a Hover (ladies and gentlemen, a steam powered hovercraft!) etc. The methanol acts as an antifreeze should you carry it around and of course has its own calorific value. But unlike NO2 it has no really dramatic exothermic whizz and is there to cool the hot parts but also 1cc to 22400cc is quite a volumetric expansion. Another day in paradise ends, Tallulah, peel me a grape!