Efficiency Optimization of Mini Unmanned Multicopter

Abstract

The article discusses three-, four-, six-, and eight-rotor UAV (Unmanned Aerial Vehicle) mini helicopters in respect to power consumption. A tricopter has most long flight time, but despite this fact, the most effective is a quadcopter. CFD (Computational Fluid Dynamics) simulations were made with purpose to find more optimal relationship between coaxial rotors. It is shown that the total lifting force generated by a pair of coaxial rotors is less than the lifting force generated by two separately standing rotors of the same size. The flow from the upper rotor in a coaxial rotor pair partially compensates the pressure near the lower rotor. The most effective is use of two rotors with the same geometrical parameters. A less efficient scheme is with the smaller rotor located on top and the larger one in the bottom.