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The Cheetah's fairing is a low drag aerodynamic shape. It was designed by fitting airfoil sections around interference measurements of the rider and vehicle. Four seperate airfoil sections are utilized in the design, each of which was custom created to optimize for low drag based on length, velocity, wobble, and air conditions anticipated at the record location. Other sections in the fairing are interpolations of these four optimized layers.
Michael Selig, Associate Professor of Aeronautical Engineering at the University of Illinois at Urbana Champagne, who at the time was an aerodynamics grad student at Penn State, optimized the airfoil sections based on the required sizes determined by the Cheetah Team. Using custom software written for the Macintosh by James Osborn, the sections were fit around the interference data. Changes in the desired section sizes were given back to Selig for further optimization. The result of this iterative process is a very smooth low drag shape.
The fairing was constructed out of carbon fiber epoxy composite material utilizing a multi-step process. First sections were cut precisely from Styrofoam slabs. A male master plug was created by stacking up these layers, gluing, smoothing, painting and buffing. Female molds were created from this master. And finally, the finished fairings (one for training and one for record attempts) were fabricated using these molds.
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In order to mount components to the Cheetah honeycomb stiffening panels were built into the frame where needed. Additionally, at the front and rear ends of the frame, where the aluminum inserts were later bonded in, the composite was layered thicker to distribute the shock loading smoothly into the composite. The inserts themselves were also tapered to a thin edge to reduce the discontinuity in stress at the edge of the insert bonding surface.
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At the front end of the frame, a large hollow aluminum insert is bonded into the frame. This insert includes features for mounting the steering tube for the front forks, the bottom bracket (pedal spindle), and the front fairing mount. The insert was designed to be rigid and yet evenly disperse into the frame composite itself the shock loading induced by pedaling and riding the Cheetah.
Similarly, at the rear of the frame, aluminum inserts are bonded into the frame to provide dropouts (rear wheel mounting locations) and rear fairing mount locations.
An intermediate gearing assembly was custom designed and built to step up the gear ratio between the front chain ring and the rear freewheel cluster. The intermediate assembly accepts standard bicycle chainrings, but actually spins upon a pair of lightweight aircraft bearings, about a fixed shaft mounted to the frame. The front chain loop is fixed and does not shift, hence the Cheetah only has seven speeds. With the intermediate gear assembly though, it is equivalent to using a chainring with over 100 teeth on a conventional road bicycle! In fact the Cheetah's lowest speed is about the same as a road bike's top speed. This makes for tricky starts since the rider is pedaling very slowly at first. This does not present a problem for a professional cyclist and with the Cheetah's low drag, the rider is able to "get on top of" that first gear in short order.