Analysis of the flight performance of small magnetic rotating wings for use in microrobots

We propose a flight system which gains thrust by rotating the magnetized wings in an alternating magnetic field. The merit of a rotating wing, compared to a flapping wing, is that it is easy to fabricate and easy to analyze aerodynamically. The theoretical analysis shows the advantage of this system in microscale. We have done experiments with large-scale models consisting of magnetic rotating wings made from nickel (or iron) and a tiny pin attached to the center, which rotates in a small glass tube that serves as a bearing. The iron rotating wings whose wing length is 5 mm could fly upwards at a rotating frequency of 160 Hz. Theoretically, the frequency necessary for flight is inverse proportion to wing length R. However, in the experiments the frequency was proportion to R/sup -0.8/. The Reynolds number of the air flow around the rotating wings is less than 5/spl times/10/sup 3/.