Types

There are two types of ducts; accelerating and decelerating. With accelerating ducts, the arrival acceleration and ability of the ballista is increased. This is the blazon that is acclimated on heavily loaded propellers or propellers with bound diameter. As Ludwig Kort performed all-encompassing analysis on this type, it is generally alleged "Kort nozzle".

With the additional type, the arrival acceleration is reduced, whereby burden is increased, abbreviation cavitation. This is alleged a pump-jet, abnormally in aggregate with anchored blades or stators.

NACA 4415.

MARIN has done all-encompassing analysis on ducted propellers. Many of the acclimated profiles are based on the NACA airfoils of which the NACA 4415 has actual acceptable characteristics. Most frequently acclimated are bill 19A and 37 of the MARIN series. Thes accept a angled abaft bend to affluence artifact and access ability sailing astern. Initially, the propellers of the Wageningen B-series were used, after the Kaplan-type with a added brand tip.