Velomobile Fairing

I was thinking about different methods for building the fairing that might be more easily shaped for an aerodynamic benefit. One method would be to use a foam core that is ruff cut to the desired shape, fiberglass and smoothed. Here is an example that shows someone using foam to shape their bike's exterior in foam. http://www.wisil.recumbents.com/wisil/barracuda/barracudafairing2.htm

Another method would be to build foam ribs and fasten thin strips of foam across the ribs to for the outer shell. A really good example is here: http://www.adventuresofgreg.com/HPB/2006/12/dec-4-2006deck-covering-until-just.html

I think both ideas would work. The rib method would probably be lighter than leaving all the foam in the velomobile, but the extra foam would allow for more impact resistance in the event of an accident. I have to way the difference in safety for weight. The weight penalty should be minimal and this is supposed to be a commuter velomobile.

Rear suspension

Here is a look into the rear suspension. I figured I could either use bushings or bearings for the pivoting point of the suspension. I am not sure what would transfer the least amount of noise to the body of the velomobile. I would think that polyurethane bushings would absorb the impact and disperse any road noise. I am not sure if friction is a critical factor with this part of the suspension. Its not a continuously moving part like the wheel bearings, which require an efficient low friction manner of spinning.

Front Suspension

This is what I have drawn up for the front suspension minus the shock and brakes. I am figuring the steering axis inclination at a 15 degree angle in the diagram. The steering axis inclination is the angle at which the two lines intersect with the bottom patch of tire and the pivoting point of the A-arms. I will do more research on suspension geometry before doing a finally design and mock up. I am trying to keep to simple geometry that should make fabrication easier. I think most of these parts can be built with patients, a drill press and a hacksaw. I will probably use aluminum because it is fairly easy to work with.

Reasonable Top

I figured I would try a different approach on my bubble top idea. I still like the idea of a bubble top, but I would need to build an oven to heat the plastic with. I could always start with no top and then build a simple top that could use the same outline for the bubble top. This would allow for the canopy's to be interchangeable.

I hope to find more people that have home built human powered vehicle and home built velomobile.

Bubble Canopy Velomobile

Well, I decided to play with the idea of a bubble canopy. Ideally, I would make the canopy deeper than in the drawing. I am trying to weight the difference between making the rear wheel enclosed vs being open. With the rear wheel being enclosed it makes tire changes and patches more difficult. An open rear tire is more easily changed or repaired and allows for a trailer to be hitched to the rear drop out, but is less aerodynamic.

The dark area around the canopy would be the hatch that would lift up and forward for the operator to enter/exit. I am exploring the idea of having the main frame being wider (20 inches vs 4 inches) then I originally planned and having a sub frame in the middle for the pedals, seat, and rear suspension. A wider frame approach would allow for more side protection in the event of an accident. I could add foam blocks between the frame and the outer shell of the velomobile, like a modern car bumper for side impact protection.

The down side to a canopy is the greenhouse effect. The canopy would have to be painted on the top to block the sun. A canopy could be made with some simple tools. It should yield an aerodynamic shape with little effort.

Designing

Well, I have been working on designing the velomobile in sketchup. I am having issues manipulating the curves in sketchup to form the complex curves for the nose. I am going to start designing the suspension parts. This will help me further my work, while getting more used to sketchup. Getting used to drawing my ideas on the computer seems to be quicker for some things. It's very nice to be able to turn the item all different directions and rescale without starting over.

I am researching joining IHPVA, International Human Powered Vehicle Association. After reading their web page it seems the organization is along the lines of what I am trying to accomplish. A human powered vehicle to get from one point to another. I am going to try and contact them to see how active the organization is. They have sub chapters around the World, but the nearest one listed on their web page is over a hundred miles away.

Bentrider Online is another resource I might explorer for getting advice. They have some active forums to communicate with.

Velomobile Foresight Begins

This is just a first draft and needs to be scaled a little better. The rear triangulated part will serve as part of the frame and shock support. It might be hollow to allow for rear wheel travel. This will allow for open additional storage and a place to place lights at the rear most part of the velomobile. Just giving an update on the progress. I have a feeling this will take several drafts before getting everything figured out. I am still learning how to use sketchup. I also need to confirm measurements to make sure I allow for the proper tolerances. Remember the old saying, measure twice, cut once.

This is a view of the bottom back of the velomobile idea.

This is a top view of the frame. At this stage, it shows the main frame and wheel wells.

Drawing Program

Well, I have been doing some of the tutorials for Google Sketchup and it appears to be user friendly. I will have to download the program and try my hand at it. Hopefully I can get it downloaded and start sketching different velomobile ideas, soon. A 3D drawing program will help with figuring out how things can better fit together.

Velomobile frame drawing

This is what my main frame idea will consist of for the velomobile. Two pieces of plywood that run parallel to one another. Then bulk heads made from 1/4 inch plywood and about two inches thick will be made to construct the shape of the sides. The front will most likely by formed in foam to allow for more curvature. I plan to router 3/4 inch groves out of the plywood bulk heads to run more thin strips of clear pine. The thin strips will be flexible enough to blend around the bulkheads.

After the strips of pine are attached an 1/8 inch thick strips of plywood will fill the void between strips of pine. This will give the final outline of the velomobile. Epoxy and a filler material will be filleted along the bulk heads and finished with a layer of fiberglass.

I am looking for a way to draw to scale on the computer. I am researching google sketchup because it is free. I hope to find something more suitable soon, then paint for the velomobile project.

Chain Routing

Attached is an option to route the chain. I want to have a geared hub in the middle to use as a transmission. This will allow for several gear ratios and help keep things simpler around the pedal sprocket. The pedal chain, left chain, would change levels with a idle sprocket, then run to the the geared hub, call it a mid drive, to the point where the rear suspension pivots. This should keep the rear suspension from tightening at pedal start up before any forward movement takes place, at least lesson the movement. A final chain will complete the power transfer to the rear tire sprocket. This is not drawn to scale and is just representative of the idea.