Thursday, December 20, 2007

Fully faired recumbent

I should receive the fairing in less than a week and I am a bit nervous to see if it looks like what I have got in mind. If required, I will make minor adjustments on the basic shape. I wonder how much bigger it is compare to Francesco's speed bike.

Final assembly. It looks like a big tuna fish on its side.

After all the parts are machined, assembly can start.

After removing the dust, the fairing is clearly vissible. As the foam sheet was too small to make the fairing in one piece, the tail is machined in the middle.

The fairing starts to appear under the dust.

The machine has started its job. There is no way back!

The fairing is already in the foam, incredible if you think about it!
The 3 sheets of PU foam will be machined separately and then bonded together.


I have started the mock-up of the frame.
I redesigned the chain path because the derailleur is either too wide between my knees or too close to my heel. The cassette will be placed below the wheel hub. I still need to check the interaction with the steering.
Anybody tried that before? What was the result?

I shaped a block of foam to get a better view of the work to come. I have decided to subcontract the 3D modelling to a friend of mine so it can be used by the CNC machine. I will still do some hand work on the foam but it should be quicker and symetric!
I have also decided to reduce the canopy size so save a bit of money during the trial and error process.

After talking to my friend Francesco Russo, I realised that my preliminary fairing (based on the shape of EIVIE I, supplied by Damjan) was too tall and too narrow in way of the crank.
Francesco kindly supplied a couple of X-sections of his bike as a guide line. There is a mistery right now because he is taller than me but fits in a smaller fairing. I am currently using 170mm crank and I can reduce it but there is a danger of designing a fairing too small. I left 10mm gap between my shoes and the fairing.
I made a 3rd attempt to design the fairing in 3D and I can't get the shape I want. It is getting better but I am now tempted to shape it by hand instead of CNC machining the foam.
I changed my mind about the frame because I think it will be quicker to do everything myself in carbon. The carbon frame will be fitted to conical female boxes (similar to a windsurf board fin).
The crank will be on the left handside so a skirt can be used to seal the wheel exit on both sides.
Main dimensions:
Length: 2911mm
Wheel base: 1437mm
Max height : 843mm
Max width: 445mm
I still need to make a moke-up of the position with MDF to check the fairing voulume required. I want to make the fairing the right size.

I have been working for sometime now on a speed machine.
This is not an easy task but the joy to ride at 70Km/h with my own (little) leg power is pushing me.
A friend of mine will CNC machine the mould and I should start the fairing construction in February.
I am still looking for some help to build the metal frame (similar to a VARNA Diablo).
I will make an attempt in May and July 2008 to set new French records.
Here is the first pictures of the fairing.