The submitted transnational project is based on the results of „VARI-SPEED“ (FFG.Nr.:850442) and the direct follow up project. VARI-SPEED showed that a rotor speed variation performed by a transmission system is possible. The efficiency and the flight envelop of the rotorcraft can be improved by this technology. Furthermore, a method for rotor blade design in a RPM area was invented.
Now, the focus of this project is to investigate the interaction of the single components in the dynamic system, from the turboshaft engine to the rotor. An investigation of the loads of a single component is not possible any more because of the dynamic in the system and the different inertias of the components. It is essential to investigate the impact of the shifting process onto the dynamic system to understand and analyse the influence of it on the turboshaft engine and the rotor.
Another research question is dealing with the controllability and the handling qualities of a rotorcraft with rotor speed variation. Also failure scenarios e.g. autorotation are investigated. Stability and controllability criteria are quantified in a simulation and should be enriched by the opinions of pilots which are testing the rotorcraft behaviour during simulator flights at the TU Munich.
The third research question addresses the realizability of the transmission ratio variable module. The compound split gearbox and the variator are designed for the scaled loads for the testbed. A controller for the output RPM is designed.It should be extended with an active vibration control system. Hardware components are defined for the controlling system and the demonstrator is designed. In addition a test schedule is created for the test in the following project.
The simulation model of the dynamic system can be used to investigate the interactions and behaviour of the drivetrain components in different flight conditions. New aspects for the drivetrain design with RPM variation can be found. Also the boundary conditions for the demonstrator test in the following project can be calculated. The findings in the simulator flight test can be used for the design of a flight control system for rotorcraft with rotor speed variation.
The aim of the project is to increase the technology readiness level (TRL) of the invention to be able to realise it together with an OEM in an European research project like Clean Sky.
