Some Aspects of the Effects of Propeller Operation on the Static Longitudinal Stability of an Airplane

Citation

Bell, Richard William and Storms, Harrison Allen (1941) Some Aspects of the Effects of Propeller Operation on the Static Longitudinal Stability of an Airplane. Engineer's thesis, California Institute of Technology. doi:10.7907/A8D1-2071. https://resolver.caltech.edu/CaltechETD:etd-12012008-095536

Abstract

This thesis is to be considered a continuation of the material presented in the paper by Dr. C. B. Millikan, "The Influence of Running Propellers on Airplane Characteristics", [ref. 1] and of the work done in the thesis [ref. 2] by Mr. S. E. Belsley on the same subject. In reference 1 Dr. Millikan has derived expressions for the prediction of the power-on effects, dependent upon empirical expressions for the power-on downwash at the tail, and the tail efficiency in the slipstream. In reference 2 Mr. Belsley has put these same expressions in forms which permit experimental determination of the two empirical factors dealing with downwash and tail efficiency power-on. It is in part the purpose of this thesis to present numerical results for these factors, determined empirically from tests run at the Galcit* 10' wind tunnel on five different airplanes. In addition there is presented a discussion of the effects on pitching moment of various rotational configurations for twin-engine mono-planes including the effects on the tail removed configuration. There has appeared in power model testing of multi-engined airplanes the existence of favorable rotational configurations giving better power-on stability than the other possible rotations. As a consequence two of the five airplanes were tested for three different rotational configurations. The experimental data have been reduced in a manner that demonstrates clearly the effect of rotation alone on pitching moment. Unfortunately, similar data could not be obtained on the other airplanes, due to the limited time available for research at the Galcit tunnel. *Guggenheim Aeronautics Laboratory, California Institute of Technology.

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