H-Airframe Benefits for Constructing Quad- Rotor Unmanned Helicopters

The H-airframe also called fuselage-airframe is a quad-rotor airframe structure that exhibits a number of benefits over the classical four-rotor helicopter airframes, but it is still underestimated and not widespread among designers. The current paper aims at disclosing these benefits and comparing the H-airframe against most well-known airframes used in the modern quad-rotor unmanned helicopters. Special attention is drawn to the dynamical characteristics of the H-airframe and how unmanned helicopters based on this airframe structure excel the standard quad-rotor airframes in mechanical rigidity, efficiency and maneuverability.