Possibilities of drag reduction on sailplanes

Abstract

The writer presents a speculative type paper. In spite of the lack of data to aid in the speculation it will be considered justified if, one individual is stirred to contribute to the advancements which surely await a conscientious study of the problem. It will be interesting to review this paper a few years hence when many of the missing data shall be available. This paper will discuss the various sources of drag, seek to indicate the theoretical lower limits of these drag contributions, and estimate the resulting improvement in sailplane performance as the drag is progressively reduced. I can anticipate the questions in the mind of the reader for the same questions exist in my own mind: Can thicker sections be employed to increase the aspect ratio without large drag penalty when stabilization is applied? How will the profile and parasite drag values vary with lift coefficient? Will stabilization through suction prove more or less costly than assumed for this study? The answer can only come through systematic and well instrumented flight studies.