Active Rotorblade Twist

Starboard has gained experience through MIT in the development of an active helicopter rotor blade for individual blade control. The concept is to apply a distributed twisting moment along the span of the rotor. As shown in the figure, active fiber composite actuators are embedded in the composite spar laminate at ±45º to generate the twist. As part of a Phase I DARPA program, MIT and Boeing Helicopter - Philadelphia designed and fabricated a 1/6th Mach-scale CH-47D Chinook blade with integrated Active Fiber Composite (AFC) actuators.

The blade, shown in the photos, incorporated 42 AFC actuators distributed in three active plies. Each of the actuators was approximately 2" by 6". In operation, the blade achieved 1º of peak-to-peak tip twist on the 5 foot radius rotor. The blade was spin-tested at the MIT Hover Test Stand Facility at full tip speeds. Transfer function data collected showed favorable authority for controlling vertical hub shear. A custom multi-layer flex circuit and an array of sensors were also embedded in the composite blade.

Technical Papers:
J.P. Rodgers and N.W. Hagood, "Development of an Integral Twist-Actuated Rotor Blade for Individual Blade Control", AMSL Report #98-6 and Ph.D. Thesis, Massachusetts Institute of Technology, October, 1998.

J.P. Rodgers and N.W. Hagood, "Hover Testing of a 1/6th Mach-Scale CH-47D Blade with Integral Twist Actuation", presented at the 9th International Conference on Adaptive Structures and Technologies, Cambridge, MA, October 1998. (0.3 Mb)

J.P. Rodgers and N.W. Hagood, "Preliminary Mach-Scale Hover Testing of an Integral Twist-Actuated Rotor Blade", Proceedings of the SPIE Symposium on Smart Materials and Structures, San Diego, CA, March 1998. (3.3 Mb)

Derham, Robert, Weems, Douglas, Mathew, M. Bobby, and Richard Bussom, "The Design Evolution of an Active Materials Rotor", Proceedings of the AHS 57th Annual Forum, May 9-11, 2001.(2.8 Mb)