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.

Velomobile Gearing

Ok, I am just thinking about how to configure the chain and had a thought about having a gear box of some sort. I was searching the net and found some internal geared hubs for bikes. It looks like one could be modified to have a gear retrofitted where the spokes attached or at the disc brake attachment holes. Looks like several company are producing them, which should allow for a variety to choose from.

The electric hub , that I plan to use as the rear tire, has five sprockets for a derailleur set up. I could use the a single speed sprocket at the pedals and attach to the internal gear hub before the rear wheel. An eight speed internal geared hub would give me a total of forty gear options with a rear derailleur. The best location for the geared hub could be the pivoting point for the rear hub, which would reduce movement of the rear suspension as the chain pulls taught. This would require at least one idle pulley between the pedals sprocket and the hub.

The other option is to bring the hub inside the velomobile and have no pulleys between the pedal sprocket and the hub, but this would still require a pulley at the pivoting point to lessen movement of the suspension as the rear chain pulls taught.

The geared hub would allow for gear changes, while parked at stop signs or lights. This definitely deserves more attention.

Steering and Suspension

Suspension

One of the first things that need to be decided is what type of suspension and steering mechanism that will be used. I plan on using a double wishbone suspension for the front suspension, unlike most commercially available models which use a McPherson strut assembly. Either design would work, but the double wishbone suspension allows the use of bike shocks. There are a lot of choices when it comes to bike shocks, from adjustable height, dampening, and load.

The double wishbone suspension is going to add weight but will allow more adjustment for the velomobile's suspension. Camber and caster will be adjustable, to an extent, with a double wishbone suspension. By being able to adjust the suspension, the performance and/or life of the tires can be extended. A double wishbone suspension has a lower and upper A arm with a shock attached to either arm.

A double wishbone suspension also allows for the suspension to attached to the main support frame, instead of adding extra support to the top of the wheel well for a McPherson suspension, which would add weight and not be as adjustable. I should be able to bolt everything together, for ease of assembly and fabrication.

Double wish bone suspension

• Adjustable Camber
• Adjustable Caster
• Completely supported by the main frame
• No weld design

Steering

The steering will be either double tiller or a steering bar. Both methods will utilize Ackerman steering. The double tiller allows for a more open feeling with nothing to maneuver around while enter and exiting the vehicle. The steering bar allow for simpler fabrication, less parts to adjust and maintain. The steering bar could pose a safety hazard while exiting the velomobile in an emergency.

The rear suspension will be addressed at a later date. I need to draw some of my ideas on the computer, or find a way to scan my hand drawings.

Velomobile Planning

Well, I am working on ideas for how to build the frame and body of the velomobile. I know I want to use two pieces of plywood for the main frame that will go from the front to back of the vehicle. I will use bulkheads like building a boat and then have thin strips of wood strung across the plywood bulkheads. I will then cut very thin plywood into six inch or smaller strips and attach them to the strips. This method should allow for the curvature of the sides from top to bottom as well as from front to back. Plywood in a larger piece would not bend in more than one direction, hence the cutting into strips. After gluing the plywood strips to the outside, I will sand it smooth and then fiberglass. The fiberglass will then be smoothed and painted.

I plan on making a model at 1/2 scale. The model will be built using full scale material, which should give me an idea of the difficulty working with different material.

Opening

Hello! This is my first post. I want to do an over cap of the velomobile project. I have done a lot of research on ideas for suspension and drivetrain. This is something that has gained interest as a way for me to travel to and from work.

The velomobile must be built mainly of readily available material, wood, fiberglass. Most drivetrain parts will consist of bicycle parts. I have a 500 watt electric assist motor to make the vehicle easier to operate. I want to incorporate working lights and blinkers for safety. It will have a bright color to stick in traffic. Did I mention, this need to be build able. I have a little wood and fiberglass experience, but no design or bike building experience.

Building material

• Wood- Main frame
• Fiberglass
• Aluminum or steel- for suspension parts

Features

• Pedal/ electric assist
• Lights/ blinkers
• Fully enclosed
• Full suspension
• Tadpole layout

I will post building ideas later. I have some drawings I will try to get scanned.