Sunday, February 13, 2011
For Valentine's Day, I made a cardboard model of a side by side tandem velomobile. The scale is 2 inches = 1 foot, and the wheels are 20" (406 or 451). As with my previous model, the goal is to come up with a reasonably streamlined shape that can be built out of flat panels and simple curves. Here are some pictures.
Saturday, January 22, 2011
Today, I made a quick structural mockup for a velomobile. This design could be built in plywood; carbon fiber sandwich panels; or any of a number of other techniques -- but it's mostly designed to be built using conventional aircraft sheetmetal techniques. Among the design influences are:
I built the mockup out of cardboard and a glue gun, around an artist's poseable mannequin. The mockup is scaled to a 6 foot tall person so, given that the mannequin is exactly 12" tall, the scale is 2" to the foot:
This mannequin was from a garage sale, and apparently, some kids had their way with him. He is now the evil brains-eating velomobilist of death from hell. His new ride looks like this:
The body is intended to have three main bulkheads, as follows:
The cockpit, i.e., the area between B and C, has curved sides; everything else is straight. The body is spanned by four longerons at the corners, perhaps made from aluminum angle:
The lower longeron is gently curved in the cockpit area; the upper one is made of two straight sections and one curved one, joined similarly to the Sonex splice plate. Both longeron curves are only in one plane, making them easy to bend.
Since the area between bulkheads B and C is open, we add two "tunnels" to reinforce it in torsion. (In my model, bulkhead B is not quite shaped like it should be.)
The seat can either be a sling, between bulkheads B and C, or a solid structure of some sort. Here is a view with the rider in place:
The front wheel structure (with or without suspension, as the case may be) is built into bulkhead A, and covered with a fiberglass fairing. Here it is with the fairing off: