Review of Rotary-Wing V/STOL Dynamic and Aeroelastic Problems

Abstract

Rotary-wing and propeller instnbilities are reviewed wilh thmc objectives: 1) to increase insight into the sources of pi.op-rotor problems, 2) to catalogue a variety of instabilities to which proprotars arc srtbjcct and 3) to suggest several important sr~hjects for research in this goncrnl won. Thc first ohjectivo is approached by contrasting prop-rotor static ~e~.oelaet.ic pral~lems with those eneonntered vith firedsing aircraft; t,he second hy a selective litornture revien which gn,ups the dynamic phenomena of interest according to (he kind of diNel.entinl equalion which characterizes them; nnd the third attom11t.s to anticipate sources of difficulty either with new configurations or in flight 1.egime.s for which we presently have very limited experience.

An Overview of Possible Aeroelastic Instabilities for Wind Turbine Blades

“…For a smaller angle of attack in stall the force will again increase resulting in a cycle that can become unstable. In helicopters this instability can occur during combinations of high thrust and/or high forward speed [25,26]. In high speed forward flight a blade can enter and exit the stalled condition during each rotation.…”