pressure jet
/ˈprɛʃə ˌdʒɛt/noun
1Attributive Designating a type of oil burner in which the fuel is burned at a nozzle from which it is ejected under pressure as fine droplets.
2A small jet engine mounted at the tip of a helicopter rotor blade and supplied with compressed air through a duct in the blade.
Origin
Early 20th century; earliest use found in The Times. From pressure + jet.