Zeitschrift für Flugtechnik und Motorluftschiffahrt
Zeitschrift für Flugtechnik und Motorluftschiffahrt (Aeronautical Engineering and Airship Transportation Times) was the official organ of the Imperial Aero Club. It started publication in 1910.
Published fortnightly in Munich (later also Berlin) by Verlag von R. Oldenbourg; subscription cost 15 marks per year. Edited by Ing. Ausbert Vorreiter, Berlin, W. 57, Bülowstrasse 73. Ludwig Prandtl and F. Bendemann were lead editors of the scientific sections.
This periodical has listings of German patents which are well indexed by issue and volume; see "Patente (erteilte)" (granted) at the beginning of vol. 3 (1912), p. viii.
This discussion in a much later patent (1995?) identifies novel work from this Zeitschrift in 1912:
- "Flapping Foil Propulsion." Thrust generation due to wing flapping was first explained by Knoller in Flug-und Motortechnik, Wien, Vol. 3, No. 21, pp. 1-7, 1909 and by Betz in Zeitschrift fur Flugtechnik und Motorluftschiffahrt, Vol. 3, pp. 269-272, January 1912. In 1936, Garrick showed in NACA Report 567 that pure wing flapping (plunging without pitching) produces thrust at a propulsive efficiency of only 50%, unless the wing oscillation occurs at very low frequency. The interest in using flapping foil propulsors therefore remained low in subsequent years. However, in 1965 W. Schmidt showed in Zeitschrift fur Flugwissenschaften, Vol. 13, pp. 472-479 that the propulsive efficiency can be increased quite substantially if a tandem airfoil combination is used whereby the forward airfoil is excited into a flapping motion while the rearward airfoil is kept stationary. He called this propulsion system a wave propeller and he demonstrated its applicability on a catamaran boat. It appears that this German work remained unknown in the United States because in 1968 Scherer, of Hydronautics Research Inc., proposed a flapping foil propulsor for use on a shallow-draft boat which used only single flapping airfoils. Quite recently, Triantafyllou and Barrett recognized that the relatively low propulsive efficiency of the single-foil pure-flapping propulsor can be improved by combining the flapping motion with a simultaneous pitching motion. This system is described in their U.S. Pat. No. 5,401,196, issued Mar. 28, 1995.
- Read online at HathiTrust (some pages missing)