[JohnAh]

I think it may be clever to base an eco-vehicle on a real vintage car, as long as you chose one that have some aerodynamic basics right, particularly in the front. Very few cars have a good rear end when it comes to really efficient aerodynamics, so adding a DIY boat-tail to a vintage car with a more rounded front may give a good platform to start with. Chosing a vintage car makes half the build done, as you get at functional chassis with simple components.

The big question is WHAT vintage car to chose. I should be obvious to chose the smallest car possible, off course with a smooth and rounded front, not the trapezoid shapes from the 1970's. I'm actually planning to let my next car project be an extreme eco-vehicle, based on an old Saab 96. The front is rounded, the wheels are far inside the fenders and almost the entire lenght have a perfectly flat belly. The rear slope is too steep, but that can be modified, and the same goes for the windscreen. I plan to attach something like a boat tail, but the most drastic modification may be to cut the roof in half and create a narrow tandem cabin to reduce projected frontal area. This may not do much in itself, but it allows a both shorter and more efficient boat tail.

For engine I hope a tiny 2-cylinder Kubota diesel may give an acceptable cruising speed, then I have two electric motors that may add another 50% of temporary power for acceleration. I'm an electronics engineer, therefore I plan to keep the electronics simple! ;-) Regenerative braking is nice to have, but it seems to be something of a marketing scam, fooling EV-buyers into thinking that braking returns you all the power, when it in fact only recycles 20-30%. For an electric or hybrid DIY vehicle the electronics and batteries can be kept much more simple and cheap if you skip the regenerative braking and instead improve the driving skills. "Driving Without Brakes" is a verry rewarding practice in any ordinary petrol car! -Learn from NASA and spaceflight, never input more power into the equation than you need for any part of the mission!