Aerodynamics

To make a bicycle go faster you either have to become super strong & fit or somehow decrease the amount of energy required to move the bike and yourself. Of course as speed rises on a bicycle the energy needed to accelerate and hold a higher speed increases also.
The best way to go faster is to improve the aerodynamics and the percentage of energy required to push a rider and their bicycle through the atmosphere is far greater than all the other factors such as vehicle weight, mechanical losses etc.
My goals include being able to ride a human powered vehicle 365 days of the year so a body shell serves two purposes for me -

1. Keeps the rider (me) from the elements such as rain, cold, sun.
2. Makes the vehicle more aerodynamic (or more efficient).

I can't see the point of putting a body shell on a human powered vehicle if it is not in some way raising the efficiency of the vehicle because the other killer in human powered vehicles is weight.
More weight = slower. So to make the most efficient vehicle it will have to be -

• Lightweight (under 22kg)
• Aerodynamic with a CdA close to or under 0.10

concept of possible bodyshell

The Start

I want a human powered vehicle! Simple as that. It needs to be fast, comfortable and be able to be used 365 days of the year.
So whats wrong with a conventional bicycle? Nothing really - conventional bikes are great and I have owned rode/raced various bikes all my life but as I have got older my needs have changed and I want to 'push the envelope'.
I have designed and built some machines of my own in the last 10 years. The great thing about tinkering and building is that you find out pretty fast what works and what does not early attempts were often 'does not' but by trying again I have come up with what I believe to be a good design.
Design criteria for my perfect human powered vehicle-

• 365 days of the year use.
• Safe - able to withstand minor crashes
• Fast (esp. head winds)
• Full suspension
• Light as possible
• Simple but elegant

My previous attempts included a recumbent tadpole trike which won me a competition in 2006 which was to design, build and race a human powered vehicle capable of carrying cargo around a urban criterium circuit, a high speed  flying 200m and a roll down speed test. I won two of the three tests and was runner up on the other.

The trike chassis used was rather conventional (in recumbent terms) for a tadpole trike but I developed a coroplast bodyshell which had cargo carrying capacity and made it more aerodynamic than a diamond framed bike.

This vehicle was pretty good but I found it to be hard on tyres and not as fast as a bicycle in corners. With front suspension of the right geometry both of these problems can be fixed. Of course I want it to be faster than  the above and aerodynamics are one of my passions and I want to be able to produce a coroplast/corflute body design which is lightweight (why drag around more weight than neccessary), rugged enough for everyday use and as aerodynamic as I can make it.