Design and Test of the Kamatics Tufflex Tail Rotor Driveshaft Coupling

The development of advanced technology driveshaft coupling supports current drive system technology goals of improved power density, reduced size, reduced operating and recurring costs, and improved safety. Kamatics has supplied its KAflex® couplings for many years as standard equipment on Bell Helicopters such as the Bell 407, 427, and 429. Recently, Kamatics developed the Tufflex® disk coupling to address rotorcraft needs and is the latest coupling technology to achieve a Technology Readiness Level 6 (TRL 6) offering excellent power density, maintainability, and life. The Tufflex® coupling is a highspeed steel coupling fully machined from bar stock or forging with zero welds, and can be designed with one or more disk flexures depending on the application. This paper will outline the testing performed under an NRTC-CRI program entitled Advanced Drive System Technology II wherein the subject coupling was developed and validated for rotorcraft use.