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In a message dated 6/4/01 8:47:36 AM EST, dfs@gateway.net writes:

<< Unless the aero gurus out there can say otherwise, it seems to me that a
fully counterbalanced, slightly heavy elevator, will have no more tendency
to flutter than any other.

Dan Schaefer >>


I think this is true of the ELEVATOR itself. However, I believe you can induce stab flutter if there is too much weight (from a heavy, fully counterbalanced elevator) hanging off the elevator hinges.

Consider a theoretical case of just the stabilizer hanging out in the breeze with no elevator attached but a certain amount of lead weight attached to the hinges. As you add more lead weight to the aft end of the stabilizer eventually it will have a tendency to flutter all on its own. This depends upon the amount of stiffness of the structure, the pitching characteristics of the airfoil, and the location of the mass with regard to the torsional center of the stab.

Considering the stab and elevator combination adds a whole new level of complexity to the flutter problem. I really only have a limited understanding of the physics involved in this case. I do know that counterbalancing the elevator is important, but I believe that the overall weight of the elevator is important as well. Many years ago I purchased a set of Rutan Longeze plans. Rutan makes it very clear that the finished, counterweighted, and painted "elevator" on the canard of a Longeze CANNOT be above a certain weight. I'm really surprised that the Lancair manual does not have a similar spec.

Paul Klusman

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