Tip-Mounted Turbojets for Helicopter Propulsion - A Progress Report

Helicopter programs, from their beginning, have been directed toward developing an ultimate tip engine. Unfortunately, economically practical tip jet propulsion cycles require that high speed rotating machinery be mounted at the rotor tip. Components other than those of the high speed rotating machinery have been operated successfully at rotor tips for some time, and the art is well developed. For the past twelve years, the Hiller Aircraft Co. has carried on tip jet propulsion programs, and simple turbojet engines suitable for rotor tip applications are now imminent. More advanced engines, such as turbofans, promise future growth of the concept presented here.