Helicopter Flapping Under Dynamic Stall

Abstract

The main journal Helicopter blade flapping with and without small angle assumption in the presence of dynamic stall by Jyoti Ranjan Majhi, Ranjan Ganguli(1) deals with the general flapping equation without taking into account the small angle assumptions. The validity of the small induced inflow angle of attack assumption is Abstract: A helicopter is an aircraft that is lifted and propelled by one or more horizontal rotors, each consisting of two or more rotor blades. The main objective of this seminar topic is to study the basic concepts of helicopter aerodynamics. The forces acting on helicopter i.e. lift, drag, thrust and weight are considered for developing analytic equations. The main topics that are discussed include blade motions like blade flapping, feathering and lead-lag. The effect of stall on helicopter blade flapping is studied and it was noticed that there is a sudden lift drop at this stall condition. It was also found that dynamic stall occurs due to rapidly changing angle of attack, which inturn affect the air flow over the airfoil. Blade flapping angle and induced angle of attack are the main parameters concerned with stall. The theory behind blade element analysis has been inferred in detail. The importance of all these in the present scenario are also taken into consideration.