Neutron Flux: Thats nice but that car recently back to the drawing board for an almost complete redesign to improve structural integrity etc. Not sure it will be on the street before the Volt, in production mode I heard they are waiting on those ultra capacitors from that unnamed company (LOL). OK for commuter car but won’t work for families with seating for 2. Nice if you can afford a limited use vehicle. Entry / exit still looks a bit difficult even after redesigning. I’d suggest trying before buying.  (Quote)

Apterra is neat and all, but it’s a two seater, not in production yet either and initially only available in CA. They’ve completely changed the dirve system since th

Dr. Ibringdoh: Excellent point!Respectfully,Dr. Ibringdoh  (Quote)

e prototype. Now it’s front wheel drive. If it fit my needs and wasn’t on the opposite coast, I might be more interrested.

Neutron Flux: Thats nice but that car recently back to the drawing board for an almost complete redesign to improve structural integrity etc. Not sure it will be on the street before the Volt, in production mode I heard they are waiting on those ultra capacitors from that unnamed company (LOL). OK for commuter car but won’t work for families with seating for 2. Nice if you can afford a limited use vehicle. Entry / exit still looks a bit difficult even after redesigning. I’d suggest trying before buying.  (Quote)

Apterra is neat and all, but it’s a two seater, not in production yet either and initially only available in CA. They’ve completely changed the dirve system since the prototype. Now it’s front wheel drive. If it fit my needs and wasn’t on the opposite coast, I might be more interrested.

Coefficient of Friction? Uh, the Volt does have wheels. I think rolling resistance is the term you are looking for.

Of course the Prius with its little 15″ wheels would probably win that.

Airdynamic surface quality has a definate effect on Cd. It can control the size and quality of the boundry layer. (Transition between free flowing air and non-moving air attached to the surface of the car).

In practice, all surfaces will be painted and the paints quality will matter more than Steel/Aluminium/Fiber Glass/Carbon Fiber.

Dimples can help in some ways (another poster mented one way, attached turblent boundry layer instead of disattached turblent boundry layer). Yet a car has an issue in that during testing it typically goes over a -wide- speed range. Some dimples that help at 60 mph, might hurt at 40 and 70. I think no Engineering department has been able to overcome the negative impulse of the look with comparable increase in mpg. (I’d drive a dimpled Prius that got 60-70 MPG compared to 50 MPG. But Dimples might get to 55….)

2.
Coefficient of Rolling Resistence is constant in relation to speed etc.

Drag= CoRR * Mass + CoAR * v^2 * rho * A/2

Its pretty hard to combine CoRR and CoAR (Cd)