5 - Pre-War Germany: –the ‘Muskelflug Institut’ and Haessler's ‘Mufli’ aircraft

Abstract

This chapter focuses on the development of the Haessler's Mufli aircraft at the Muskelflug Institut in prewar Germany. The results of the work of Oskar Ursinus carried out at his Muskelflug-Institut have remained among the most comprehensive and reliable data on the power outputs of human beings. Details of the vast majority of his experiments related to man-powered flight were published in Germany in 1936, and covered measurements made on men in a variety of attitudes from the conventional cycling position to the fully reclining and prone positions. A number of methods for propelling such a vehicle were tried, including rotating, reciprocating, and rudder movements. Helmut Haessler, a glider pilot, began a series of experiments in 1933, which were to lead to the construction of a successful man-powered aircraft. The Haessler–Villinger Mufli was a single seat monoplane with a layout similar to that of typical gliders of the period, with the addition of a pylon above and forward of the wing leading edge, on which was mounted the pusher propeller. A conventional glider-type control column was used in the rather cramped cockpit of Mufli, and normal movements were retained for longitudinal and lateral control. The data presents the Haessler–Villinger aircraft in an extremely favorable light, but the weight of the drive system and the indirect weight of the propulsion unit is underestimated.