HYBRID MULTICOPTER DESIGNS

Hybrid unmanned aerial vehicles are vehicles that employ more than one type of energy delivery system for powered flight. Hybrid drones are not restricted to using electrical power. Nevertheless, most such drones employ electric propulsion by implementing brushless three-phase electrical motors in their rotors due to the inherent high efficiency and ease of control of such devices. Electrical energy for the motors is supplied by various sources such as batteries, hydrogen fuel cells, internal combustion engine electrical generators, etc. The current battery technology offers flight times from 10 minutes to 2 hours, depending on the payload and drone design. For longer flight times, a hybrid power system is required. The common hybrid drone design involves a combination of batteries and an internal combustion engine electrical generator. The current article introduces two novel hybrid unmanned aerial vehicle designs. The first exhibits improved efficiency due to the implementation of a hybrid power system powering two horizontal tandem counter -rotating direct driven rotors and at least four electrically driven smaller horizontal attitude control rotors. The second presented herein invention offers the addition of a horizontal rotor or rotors, rendering the design a compound multicopter. The vertical rotor or rotors are also direct driven improving efficiency.