A New Test Stand for Tension Testing of Planetary Gears for Aircraft Engines

Kurzfassung

The aviation sector is evolving as it seeks to cut emissions and improve the efficiency and sustainability of jet engines. A promising solution for next generation high thrust aircraft engines is the incorporation of planetary gearboxes that decouple the fan and low pressure turbine. While this concept offers clear benefits, it also raises demanding technical and safety requirements: the gearbox must provide high power density, be lightweight, highly reliable, and compliant with aviation safety standards. As a single gear bursting would constitute an unacceptable and highly dangerous incident, intensive testing of the individual components, especially the gears, is necessary to ensure that all requirements are met.

To meet these challenges, the German Aerospace Centre (DLR) at the Institute of Test and Simulation for Gas Turbines has developed a dedicated back to back test rig with a closed power circuit. The rig replicates realistic operating conditions for planetary gears—speed, torque, and temperature—while allowing independent control of each parameter. Its primary purpose is to assess gear reliability, damage tolerance, and crack growth using both pristine and pre damaged components.

This paper details the design, development, and commissioning of the test rig, highlighting the special requirements for high power density and the use of pre damaged gears. Performance data, conformity with requirements, and the functionality of specialised measurement systems are presented based on data measured during commissioning. Precision of the control parameters is examined under maximum and intermediate loads, and the feasibility of damage propagation measurements is qualified along with the associated uncertainty of measurements.

The results demonstrate that the rig meets its stringent design goals, providing a reliable, reproducible platform for the qualification of gears for planetary gearboxes intended for the next generation of sustainable aircraft engines.