Velomobile development drawings: Part 1

My aim in designing this new velomobile was to make it as simple as possible while reducing the effort to push it through the air. I also wanted to make something with as few compromises as possible.

The major influences at work in this design is the invention of Jurgen Mages and his Python recumbent bicycle geometry. This went completely against the RULES of bicycle steering geometry and created bikes which not only steer and handle but have done so over thousands of miles of commuting and touring. Please see in

http://en.openbike.org/wiki/Main_Page

One of the biggest sources of drag in a land traveling vehicles are the holes needed to clear the wheel(s) when they steer. Reduce the clearances to a minimum and you are doing as much as you can.

This image shows the plan view of a 20 inch 406 BMX front wheel. The aero profile is Eppler 214 Low Reynolds number which is calculated for low speed air flow. The ellipse is to give enough clearance for tyre punctures while not creating interference drag. The leading edge profile comes from the ellipse.
I could not imagine what this might look like, so I had to generate it to find out. This latest design completely changed my approach. Usually I draw what I want and then work on it until I am happy with the result. This time I set out the rules and see what comes about and worry about making it later.

The wheel does not pivot in the fairing, so pivot the fairing, this creates aero problems with the axle/fairing join. Simplify the whole front end and make the wheels, fairings and axle one piece. This does away with pivots, uprights, steering arms, rose joints and a mass of nuts bolts and washers.

“Nothing weighs less than nothing”

The next step was to put the disk brakes in-board. The axle then only had to deal with bending forces, all torsional braking forces are dealt with in the central structure leading directly into the chassis.

Make the nose of the body one piece with the axle and the messy aero join is avoided. Now bend the body to steer the wheels. So far I have come up with 3 ways in principle to do this.

Leave a Reply