Holistic approach for development and optimisation of helicopter gearboxes

Abstract

Design and development of drive-trains, especially gearboxes for helicopters, can be done using different development processes. Considering the time-to market and development costs, ZFL has developed a holistic approach for development and optimisation of helicopter gearboxes. This paper will at first describe this holistic design approach. It will show the base elements – starting with an analysis of the rotorcraft drive-train system, including an integration of full-FEA gearbox models, integration of external influences coming from the surrounding aircraft structure into a full-FEA simulation model and the analysis of simulation results based on “Virtual testing” using validated calculation models. In the second part, this paper will focus on one of the latest technology developments, where ZFL’s holistic development approach resulted in a non-standard technical solution, which is used within intermediate gearboxes for helicopters. The development was performed for a given helicopter model range, where an upgrade program was launched to operate with higher performance and to increase the MTOW. As a result from the development program, a new gear design – where no standard calculation method is available so far – was introduced resulting in significant improvement concerning life time and increase of load carrying capacity. This paper will show the different steps within the development process from drive-train analysis, over full-FEA simulation to prototype testing and technology verification “first time right”. Relevant results from simulation and bench testing will be shown and discussed.