Presents a simplified method of designing ducted fans for light aircraft propulsion. Includes a survey of ducted-fan-powered aircraft, ranging from amateur-built airplanes to military models and prototypes. Detailed discussion of engines and list of suitable powerplants drawn from automobiles, ATVs and personal watercraft. Extensive technical bibliography and list of sources.

The potential noise problems anticipated with future VTOL aircraft are analyzed and discussed in general terms, and a brief review of the basic principles of noise generation of various types of propulsion systems proposed for VTOL is included. Primary consideration is given to the noise environments produced in areas adjacent to VTOL sites, since they could cause the most serious noise problem limiting the usefulness of VTOL aircraft. Contours of perceived noise levels are compared for different takeoff and landing profiles of 3-4 passenger, 60 passenger, and 25 ton-lift-crane VTOL aircraft. Criteria and methods for assessing the response of communities to noise from V-port operations are discussed along with the problem of detection of military VTOL aircraft by means of noise. Recommendations are given on the requirements for future research on these noise problems with emphasis on the need for considering noise as an integral part of the design, selection, and test of VTOL aircraft.

Power, free-stream velocity, and duct angle of attack were varied at several wing angles of attack to define the aerodynamic characteristics of the ducted fan, wing, and of the ducted fan wing together. At large duct angles of attack, the inside of the upstream duct lip stalled causing a rapid change in the duct pitching moments and an accompanying increase in the power required. At low horizontal velocities, this lip stall would probably limit the rate of descent of a vehicle with a wing-tip-mounted ducted fan. During low-speed, level, unaccelerated flight (30 to 80 knots) it appeared that a vehicle, with a configuration similar to that examined, would require less power if it were supported by a wing and ducted fans than if it were supported only by ducted fans. (Author).

The performances of VTOL aircraft using ducted and free propellers are compared The comparison is based on existing light VTOL aircraft equipped with ducted propellers and on the same aircraft using free propellers computed for this purpose. The free propellers appear to provide better aircraft performance, especially higher flight speed. An appraisal and analysis of VTOL aircraft based on the existing VTOL testbeds forms the second part of this volume. Summaries of design particulars and performance re given in graphical and tabular form. The special purpose vehicles, such as the flying jeeps, aerial platforms and aerodynes, are treated as a separate group. Particular performance data of the various VTOL aircraft are collected in an appendix.