Are usual electro-hydraulic actuator designs for aileron control employable for aeroelastic flutter suppression? If not, where can I find design procedures for this specific case? 


This 1986 USAF experiment might help.

The purpose of this test was to demonstrate in flight for the first time the feasibility of powering a primary flight control surface with an electromechanical actuator (EMA) in place of the standard hydromechanical actuation system. An advanced development model model EMA drove the left aileron on a specially modified C-141A aircraft and was to duplicate the functions of the standard hydromechanical unit. Lockheed-Georgia Co. (GeLac) was the prime contractor with Sundstrand Corp. as the subcontractor.


The C-141 aileron is statically and dynamically stable with the critical flutter parameters being tip weight and actuator stiffness. If either parameter were not present, the damping would still be sufficient within the aircraft normal operating envelope. Laboratory studies had shown that the stiffness or spring rate of the EMA was identical to the hydraulic unit. All else remaining unchanged, the structural damping of the modified aircraft was expected to be the same as that of the baseline aircraft. The baseline aircraft has a flutter margin more than 20% above the normal operating limitations of the C-141A, and well above the military specification (MILSPEC) requirements.

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  • $\begingroup$ Is this EHA design also fit for flutter suppression? I see it is only designed to have a hydraulic stiffness sufficient to avoid flutter within the design envelope. Is this a sufficient condition for it to be fit also for active flutter suppression? $\endgroup$ – Mirko Aveta Feb 13 '17 at 9:17

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