PRELIMINARY ANALYSIS OF HOVERING AND CRUISING PERFORMANCE FOR THE TRIDENT VTOL AIRCRAFT CONCEPT

Abstract : The Trident is a hypothetical tail-sitter VTOL aircraft, with a tip-jet-driven three-bladed rigid rotor, which becomes a Trident wing with tip propulsion jets upon transition to cruising flight. A simplified system of equations for hovering and cruising performance is presented and applied to obtain performance estimates for a family of nine configurations, differing in rotor planform geometry. Results presented are confined to the cold-jet case, and to the operating mode, wherein the rotor is locked into a fixed-wing configuration during crusing flight. The results indicate that thhe T1rident concept may afford a comparatively good compromise between the competing requirements for hovering performance and cruising efficiency, despite rather severe performance penalties associated with the restricted space available for air ducts within the rotor blades. Final conclusions on the merits of the Trident concept are deferred, pending development of information on transition-flight stability and control, and rotor weight and structural integrity. (Author)