Print Friendly, PDF & Email

Arie Egozi

A revolutionary electric motor developed by American company Polarix is creating great interest among Israeli Unmanned Aerial Vehicle (UAV) manufacturers and will soon be tested on a UAV in the country to increase its efficiency and range, enabling new capabilities for military forces. In cooperation with a fan jet engine company, Polarix is developing a battery powered all electric Vertical Take-Off and Landing (VTOL) UAV with enhanced range and endurance by modifying a high Lift-to-Drag (L/D) ratio UAV airframe. This new system is aimed at providing military organisations with a unique surveillance platform that will be quieter and easier to launch/recover than current UAVs in use with military forces.

The key disruptive technical component is the development and integration of a new class of Li-ion battery powered electric motor called “Arrayed Controlled Turnless Structures (ACTS) and its integration into the rim of a propulsion fan. This integration into a high L/D air frame will provide the required VTOL thrust with minimal reduction in its aerodynamic efficiency. The concept is based on the ground breaking development by Polarix of a new type of propulsion motor which was originally developed under a US Department of Defence programme for flight control actuators.

Increased efficiency

Presently, all-electric VTOL craft are substantially diminished in range and endurance due to their very large cumulative fan area requirement which reduces aerodynamics and the L/D ratio. The later reduces both range and endurance but the Polarix solution takes advantage of the much higher specific, and thus total, power, available from the ACTS motor and power supply to produce the full VTOL thrust, concurrently serving as the cruising propulsion fan at much reduced power.

At present, long range UAVs are either catapult launched or use a runway and wheels under power from a piston engine and fuel tank. Their replacement by the electrical rim driven fan and batteries will allow meaningful structural weight savings which Polarix estimates will reduce the dry weight from 37% to 33% of the craft. Over the last few years, Polarix has developed and patented this enhanced specific power motor technology and recently designed a Rim driven fan configuration with a fan jet Engine company.