Theory 36/Aerospace Structures
Flutter Is a Speed Ratio
The claim
Flutter onset is set by the ratio of flutter speed to dive speed, so a design with a small margin is sensitive to small stiffness changes.
01Mechanism
Flutter occurs when aerodynamic and structural frequencies coalesce; the margin is the gap between the speed at which that happens and the operational limit.
02Predictions
- P1Margin should track the ratio.
- P2Absolute flutter speed should mispredict across envelopes.
03Refutation
Safety tracking absolute flutter speed would remove the ratio.