Wiktionary
n. (cx chiefly aeronautics English) A propellor enclosed in a short cylinder, that can typically be swivelled to change the angle of thrust. (from 20th c.)
Wikipedia
A propulsor is a mechanical device that gives propulsion. The word is commonly used in the marine vernacular, and implies a mechanical assembly that is more complicated than a propeller. The Kort nozzle and pump-jet are examples.
An example propulsor is shown in the accompanying picture. It has a shroud which cuts down on blade-tip cavitation and radiated noise. It also has a rotor element and a stator. The stator concentrates the thrust in axial direction and reduces energy wasted in the tangential flow (therefore eliminating torque on the hull). The number of blades in the rotor & stator will typically be two different prime numbers to avoid standing waves. The blades in the rotor or the stator may be angled to further reduce noise. The physical design and layout is very much similar to a single stage axial-flow compressor.
Usage examples of "propulsor".
PROPULSOR Sophisticated screw that uses ducting and multistage water turbine blades for propulsion instead of a conventional screw.
The drone comprised only three elements: a tiny tachyon receiving unit, built around the crystal from Auroras own, in a globular body fitted with weak handling propulsors, suitable only for correcting minor errors in the elements of an orbit.
Vast and lumbering, the creature flew out from Vormspire with the rumble of its propulsors echoing over Turgosheim, its armour glinting ruddily in the lights of the manses, and its exhaust vapours shaped by the winds into a fantastic, billowing slipstream.
Propulsors blasting, the vampire warrior lowered its head and zeroed in on them!
Propulsors blasting, the warrior lowered its head and zeroed in on them!