Innovative Systems to Reduce One per Rev Vibrations in Helicopters

Significant maintenance activity is required to ensure acceptable 1/rev vibration levels from main and tail rotors. These flight and ground based maintenance activities translate into significant cost and downtime for the helicopter operator. Cost has been somewhat mitigated with the use of on-board systems with computerized diagnostic algorithms. The result is better ride comfort which translates into minimized pilot fatigue, and better helicopter and component life. The rotor tuning adjustments typically used are blade pitchlink length adjustment, trim tab angle adjustment, and rotor weight balance adjustment. These adjustments are manually implemented in a relatively inefficient way that is time consuming and sometimes prone to error. Ultimately an overall system is desired that would enable relation of the results of the computerized diagnostic algorithm to the automated rotor adjustment implementation system in an automated way such that the changes are made in a quick, efficient, accurate, repeatable, and error free manner. Midé proposes to develop two innovative, robust solutions to adjusting the pitchlink length and rotor mass balance. Midé has recently developed an active trim tab and successfully tested it on a whirl stand. These systems will be automated and would ultimately be adjusted in flight.