Sizing methodology for reaction-driven, stopped-rotor vertical takeoff and landing concepts

Abstract

Reaction-driven, stopped-rotor, vertical takeoff and landing (VTOL) aircraft concepts offer great potential for application by allowing the use of a common propulsion system for high-speed cruise and low-speed powered lift. Using the rotor for lift in both flight modes increases its utility. Existing analysis and design methodology for shaft-driven VTOL concepts, like helicopters or tilt-rotor and tilt-wing aircraft, cannot be applied to reactiondriven, stopped-rotor concepts. The methodology for sizing this type of vehicle is presented, addressing both internal gasdynamics and external aerodynamics, along with consideration of their noncomplimentary interactions. Aerodynamic compromises required to obtain flight in both fixed- and rotary-wing modes are presented. Lessons about design issues and tradeoffs learned during the development of this methodology and its implementation are discussed. Finally, the results of applying this methodology to an example of this type of vehicle, the canard rotor/wing, show its utility.