Conceptual design, thrust test, and finite element analysis of a tip-jet rotor using a small turbo-jet engine

A general helicopter uses rotary power produced from the installed engine in order to get the directional thrust. In the case of a tip-jet rotor helicopter, the compressed air or the combustion gas passes through a duct system inside rotors and is ejected out of the nozzle at the blade tips to produce torque enough for rotation of the rotor system. The generated torque makes the rotor system rotate, so that it can create the directional thrust. Since the anti-torque does not occur in this tip-jet rotorcraft, the tail rotor can be removed, which can be very attractive. In this paper, a power system for a reduced-scale tip-jet rotor by using a small turbo-jet engine is designed and tested for feasibility study. The in-plane thrust that the power system can produce is measured and compared with the calculated one. Finally, the finite element analysis of a conceptually designed tip-jet rotor is performed to ensure structural safety.