Contra-rotating propeller for fixed wing MAV: part 2.

Purpose - This is the second of two companion papers presenting the results of research into a contra-rotating propeller designed to drive a super manoeuvrable micro air vehicle (MAV) and is devoted to the experimental results. The first paper presented the design process and numerical analyses. Design/methodology/approach - Most of experiments were conducted in the wind tunnel. Both contra-rotating and conventional propellers were tested. The test procedures and equipment are described first. The attention is focused on the design of an aerodynamic balance used in the experiment. Then, the measurement error is discussed, followed by presentation of the wind tunnel results. Finally, an initial flight test of the MAV equipped with contra-rotating propeller is briefly described. Findings - Wind tunnel experiment results fall between theoretical results presented in the first part of the paper. The application of contra-rotating propeller allowed to develop the propulsion system with zero torque. Moreover, the efficiency achieved appeared to be a few percent greater than that for a standard conventional propulsion system. The concept was finally proved during the first test flight of the new MAV. Research limitations/implications - The propeller was designed for a fixed wing aeroplane, not for helicopter rotor. Therefore, only conditions characteristic for fixed wing aeroplane flight are tested. Practical implications - The designed contra-rotating propeller can be used in fixed wing aeroplane if torque equal to zero is required. Originality/value - Original design of the balance is described for the first time, as well as test procedures applied in this experiment. Most of wind tunnel test results are also new and never published before. [ABSTRACT FROM AUTHOR]