The Design and Performance of Shrouded Propellers

The shrouded propeller is a natural propulsive device for VTOL. This has been proved by a demonstration of good VTOL capability in actual flight by a shrouded propeller VTOL airplane. Thorough theoretical studies and tests of the shrouded propeller have been made. By means of potential flow calculation on automatic computers, pressuredistributions over shroud shapes have been determined at static, transition, and cruise flight. Momentum theory has been used to determine shrouded propeller performance, and wind tunnel tests have verified theoretical calculations. Excellent agreement between experiment and theory indicates that the methods described here provide good design and performance.