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Old 01-01-2020, 05:07 PM   #1 (permalink)
Frank
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Join Date: Jan 2008
Location: Maine/Nova Scotia
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Homemade Motorcycle Tail Section

I've been involved in land speed racing for a number of years, mostly with the Loring Timing Association, which races at the old Loring AFB in Limestone, Maine. I've run a number of bikes and have gone over 200 mph on my electric Hayabusa (E-Busa) with OEM bodywork (with the exception of the front fender). I've been thinking about improving aerodynamics for quite some time, have asked questions here, looked at the Template, etc. and have been paying attention to fast bikes using commercial bodywork, mostly LSR fairings from AirTech. These fairings are quite good - possibly *too* good - which is what led to this project.

There seems to be a lot of experience with the commercial fairings indicating they are extremely susceptible to any sidewind component. There have been crashes and scary moments as described by the riders. I don't have any data on Cg/Cp locations, but the tails seem pretty big and I would expect this relationship to be okay, plus AirTech has spent time in the wind tunnel and I'm sure are quite aware of how important this is.

My theory is that the fairings are excellent airfoils which can develop lift fairly easily with anything but a dead-on head or tail wind. One of the NASA simulator programs (I think I used FoilSim) showed it wouldn't take much to develop 100-200 pounds side force. Accordingly, I decided to build something that was less than optimal, hoping to avoid the crosswind susceptibility issue while simultaneously improving performance.

Does this make sense to you guys?

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