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.

Semi-monocoque velomobile chassis

Still fine tuning the monocoque design.

Will prototype full size out of plywood to test size and rigidity of design. Enough computer work!

Wonderful Wooden Chassis

Came across this beautiful chassis design. It is not human powered but would be easy build something similar to this for a velomobile chassis. I love the simplicity of it and of course the sustainability of building in such a way. This has inspired me to go down this route for the design of Veloci-Velo chassis. I had almost finished a more conventional aluminium frame type chassis but when I saw this I changed my mind. Stay tuned as I make up some drawings and then get to work!

More info about this design here ... https://tadpolerider2.wordpress.com/2014/09/04/electric-recumbent-trike-race-wood/

Velomobile Plans

Now that I have finished the design phase. It is now time that I got on with building Veloci-velo!
I sent the unfolding file to a large format printer to get printed out at 1:1 scale. At this size the coroplast needs to cut out the bodyshell is only two sheets which equates to about 2kg which is what I calculated and hopefully will keep the total weight of Veloci-velo below 22kg (48 pounds).

Plans at 1:1 coming out of the printer.

Here is a image of the plans with the 'mule' chassis in position on the floor plan.

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.

Velomobile in Virtual Wind tunnel

Since I have established the final shape which now has a larger opening and is wider at the shoulders to accomodate the rider. I thought I better re-run the final shape in the virtual windtunnel to get an idea on how aerodynamic the shape is.

The results surprised me a little with the figures coming back at a Cd factor of 0.20 at a velocity of 11.2 m/s or 40kph. This was excellent as I was expecting the Cd figure to be a little higher with these changes. Now with a frontal area of 0.35m2 the CdA is now 0.07!

This final design is the result of appox. 200 hours testing and tweaking in the virtual windtunnel. I am confident that the figures are pretty close as I have calibrated the results against shapes of a known Cd figure.

Veloci-velo Velomobile 2014©

Power required to have a velocity of 40kph is a very achievable (for the majority of people) 122 watts.

see below...

High Quality Veloci-velo renders

In a moment of spare time while designing the chassis and suspension, I decided to render a few high quality images of Veloci-velo in it's final format. Design changes include a larger entry/exit hole and wider at the riders shoulders. I hope to have some more info on the chassis soon and get building!!!

LHS

RHS