vacuum
atmospheric air
compressed air
oxygen alone
liquid hydrogne
high speed diesel oil
kerosene
demethylated spirit
peopeller
diffuser
intercooler
turbine and combustion chamber
thrust power and fuel energy
engine output and propulsive power
propulsive power and fuel input
thrust power and propulsive power
high calorific value
ease of atomisation
low freezing point
(a) and (c) above