Design of a Transmission System For A Mini Helicopter

Pandey, Satyavrat

Design of a Transmission System For A Mini Helicopter by Satyavrat Pandey - IIT Jodhpur Department of Mechanical Engineering 2019 - xvi,67p. HB

In helicopters, the power from the engine has to be transmitted to the rotor system viz. main rotor, and tail rotor to rotate at prescribed RPM. Hence, the transmission system is one of the critical subsystems of a helicopter. The transmission system depends on the configuration of helicopter, whether it is conventional single main and tail rotor configuration, or tandem rotor, or coaxial rotor, or side by side rotor, or intermeshing rotor, or NOTOR, or FENESTRON, or tip jet configuration. The aim of the present thesis is to design a transmission system for a single main and tail rotor helicopter configuration of a mini helicopter in the weight class of 200-250 kg with an engine power of 41 KW.For transmitting power from engine to the main rotor, a main gear box (MGB) has been employed. Thepower is transmitted to tail rotor through tail gear box (TGB). The MGB comprises a set of bevel gear, planetary gear train, and helical spur gear. The poweris transmitted to TGB through MGB via helical gear set. The TGB comprises of one set of helical spur gear. A parallel connection between MGB and TGB is made for engine power distribution. It is assumed that approximately 10% of the engine power is required to be transmitted to tail rotor at maximum operating condition. The layout of MGB and TGB has been accomplished by considering numerous design aspects like, engine location, geometry and weight. Solid rotor volume optimization technique is used to take care of weight consideration. This technique provides an optimized gear ratio (GR) for transmission system which is used while designing the system. The present design is based on static loading condition, considering the maximum torque supplied from engine. The transmission system consists of several components, like gears, bearings, shaft and couplings. The sizing of gears is determined based on bending and contact stress. The selection of bearings is based on load and life requirements. Shafts have been designed on the basis of torsional rigidity criterion. In addition two sets of flexible bushed pin coupling have been employed at tail drive shaft to account for misalignment. The software tools Matlab and SolidWorks are used during the design process.



Transmission System For A Mini Helicopter
MTech Theses
Department of Mechanical Engineering

629.2 / P192D