Elevation of semi-monocoque velomobile

Here is an elevation showing the position and size of the semi-monocoque chassis. Attached to the monocoque will be the rear swingarm, and the front a subframe to locate pedals and front suspension pickups. Again using a semi-monocoque will hopefully make for a lighter velomobile. The semi-monocoque will have to be stiff enough to take loads from the subframes without excessive bending or twisting. I have decided that a good quality plywood would be best for the monocoque for cost for performance.

Semi-monocoque

Semi-monocoque velomobile

Final render of velomobile semi-monocoque to be manufactured from plywood. The render does not include a few cut-outs for other components. I hope to get the final weight of this component down to less than 5 kilograms. This final design allows a 'safety capsule' around the rider a feature that I really wanted to have. Making from plywood makes an easy build and the possibility of a true 'flat pack' kitset velomobile. I am exploring the possibility of this being a Open Source Velomobile as this may lead to faster development once the basic design has been done.

©2016 James McLeod

Semi-monocoque velomobile

Final render of velomobile semi-monocoque to be manufactured from plywood. The render does not include a few cut-outs for other components. I hope to get the final weight of this component down to less than 5 kilograms. This final design allows a 'safety capsule' around the rider a feature that I really wanted to have. Making from plywood makes an easy build and the possibility of a true 'flat pack' kitset velomobile. I am exploring the possibility of this being a Open Source Velomobile as this may lead to faster development once the basic design has been done.

©2016 James McLeod

Velomobile front beam suspension design

Most commercially availible velomobiles feature Macpherson Strut independent front suspension. A popular choice for full monocoque designs.

Tadpole design three wheeelers require roll stiffness at the front because the single rear does not have anti-roll stiffness so suspensions have to be correspondingly stiff to reduce body roll.
I intend to have a very simple beam front suspension with the advantages being...

• Simplicity
• No track variance when bumps encountered (zero scrub)
• Can be made lightweight (for velomobile applications)
• Great roll stiffness

The beam axle can be mounted to the monocoque section using four elastomers which will be the spring and damper all in one. The benefit of this is that the elastomer will provide vibration isolation and reduce the "road buzz" to the occupant. This isolation reduces the fatigue on the occupant.

Go to this link to see a an arguement for a beam axle front Vs Macpherson Strut.

Velomobile Chassis monocoque

Semi- monocoque design for Veloci-velo.
Sub frames for front and rear yet to be finalised. This design is really the best compromise for crash protection Vs weight.

Measurements

Using the 'mule' I have been fine-tuning the dimensions of Veloci Velomobile. I have changed the design of the frame to have a perimeter upper frame to provide extra impact protection and added torsional strength. At the moment I have been setting up the 'mule' to check seating position and clearances for wheels, steering bits and of course the rider to bodyshell interferences. I have found by doing this that I can make the Veloci-velo even a little bit smaller than I had planned with the entire bodyshell being able to envelop me the rider as close as possible.

The 'mule' test rig for Veloci-velo

This was one of my goals in building this velomobile and that was for it to be a scalable design instead of a "one size fits all" policy. In a production version the rider would supply the essential measurements and the bodyshell would be custom designed to fit his body / seating position. The chassis would be basically the same for every rider but the shell would specific to the rider.

Velomobile Frame Design

I have been coming up with different ideas on the design of the velomobile frame. I have decided that including some sort of impact protection would be a good idea so the above idea has 'side impact bars' which also double as handles to aid getting in and out of the velomobile.
I also want this frame to be stiff in torsion as well as bending forces as a stiff chassis makes for a better handling vehicle. I have chosen aluminium as the material for the frame as it is a material that when used with large diameter and thin walls both stiff and lightweight.
The seat is formed from plywood and will have a little adjustment fore and aft with the bottom bracket providing most of the adjustment for different size riders