Masters Theses

Date of Award

5-1992

Degree Type

Thesis

Degree Name

Master of Science

Major

Aviation Systems

Major Professor

Ralph Kimberlin

Committee Members

Donald Tippet, Bob Richards

Abstract

This treatise has researched the modification of body position, wheels, and use of aerodynamic enhancing devices to significantly reduce the drag and increase the speed of the recreational cyclist. This thesis has evaluated several ways in which aerodynamic improvement can be made, the cost versus drag savings factor, and ergonomics. When traveling on level ground, cyclists dedicate 90% or more of their energy overcoming wind resistance or drag. Previous wind tunnel testing and outdoor evaluations have determined that the retarding force due to wind resistance increases proportionally to the square of the velocity. The two principal causes of wind resistance are pressure drag and drag produced on surface imperfections. Pressure drag can be significantly reduced by streamlining or lowering the cyclist's frontal area and of the two causes involved has the greater effect. Drag due to surface imperfections is caused by holes, gaps, roughness, and protrusions. Reduction usually requires costly modification and therefore was not addressed here. Outdoor testing was conducted and compared to a baseline cyclist in a racing position. Modifications were then added or subtracted one per run and the data for each run were recorded. Each configuration was evaluated during a coastdown study and at several different gearing ratios on a level course which resulted in data being obtained for a range of speeds. Wind conditions were less than two knots during all testing. Results were verified for repeatability. It was concluded that the recreational cyclists can significantly increase speed for the same power output through the use of several different aerodynamic devices. Although cost of the devices varied, significant reductions were attained through the use a less costly alternatives. The testing conducted for this thesis allowed the author to take important steps of obtaining knowledge through the experience and aerodynamic refinement of a fairly simple vehicle, the bicycle. Techniques similar to the ones used in this evaluation could be applied to any form of human propelled machine be it a commuter vehicle, wheel chair, an airplane, a helicopter, or a submarine.

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