Aircraft Flutter

What is flutter?
Flutter is a catastrophic yet fascinating phenomenon that can happen to an aircraft flying at high speed. Flutter is one of the most important aspects that engineers have to care about while seeking the design certification of an aircraft. Basically it is an unstable oscillation of the airframe, the wing, possibly the tail, or another component. This is due to the interaction of three different forces acting on the aircraft in flight. We have the inertial forces, due to the mass on the aircraft. The elastic forces due to the airframe, and the aerodynamic forces. The interaction between these three forces generate oscillation. Each force interacts with the other one, aerodynamic forces generate inertial forces, inertial forces in turn deform the airframe structure, which in turn change the aerodynamic forces due to the change in shape. Depending on the characteristics of the aircraft, this may lead into an unstable phenomenon called flutter. The role of the engineer is to design the airframe, the aerodynamics, and the mass in such a way that this phenomenon does not occur within, or even well above, the flight envelope of the aircraft.