An Investigation on the Aerodynamics of Flight of a Hand Helicopter

Abstract

A simple hand helicopter can be made by attaching rotor blades to one end of a vertical stick. The helicopter moves upwards when the stick is spun above a threshold angular velocity and released — a mechanism of common toys found in toy shops. This study uses computational fluid dynamics to predict the airflow around a hand helicopter from which the lift and drag acting on the hand helicopter’s blades can be obtained. Newton’s Second Law is then applied to find the hand helicopter’s equations of motion. These are solved to predict the helicopter’s trajectory and maximum height. The angle of attack, length of blades and thickness of blades are varied and their effects on the lift coefficient, drag coefficient, lift-off and maximum height are investigated. The findings offer insight into the parameters which will allow a hand helicopter to achieve its optimal maximum height. The conditions required for the hand helicopter to fly stably are also investigated and explained using the Tennis Racket Theorem.