Designing an FE Car from the ground up.

[Mighty Mira]

Toecutter, I like your way of thinking.

I've always been a performance nut too, long before I started caring about fuel economy. And I think something shaped like the Precept and done the way you are talking about according to the criteria you set out would sell.

But since I started getting in on the FE kick, the engineer in me sees the shape of current cars with the Cd of 0.33 or so, and then a dolphin with Cd of 0.004, and sees an improvement to be made of approximately 80 times! Of course, if that figure is to be believed. This link makes me think otherwise.

Even just the streamlined body is 0.04, which is about 8 times better than what most cars are currently.

And seeing as cars like the following sold once:


It should be possible to have the driver in a more forward position, which gives more room for the boattail, and hence, lower Cd. It also means more usable space, since there is no penalty to starting out with the largest cross sectional area fairly early.

The Mercedes Benz Bionic Car is a step in the right direction, but even that is a little compromised IMO.





Both articles are well worth reading btw.

Of course, if you want to really optimize for low Cd, something like the Sailfish, Tuna or Mackerel are good to observe.

Sailfish (note that the sail is down at top speed, it folds back into a groove):


Yellowfin Tuna:


Mackerel:


Mako shark:


Marlin:


All are essentially streamlined bodies in three dimensions, somewhat elongated I suspect to make changing direction/propulsion easier.

I guess I just like the idea of reducing my vehicle costs to practically zero, especially over long distances at highway speeds. Equipping a car to get FE equivalent to such low drag means of course reducing engine size OR pulse and glide driving. Both have their downsides - P&G means that cruise control is not practical, you need a larger starter motor and a good way to control the engine properly, to turn it on and off safely etc. A reduced engine size lawnmower style motor means that getting up a steep hill will mean slowing down significantly.

A couple last pictures: the Orca or Killer Whale:




Note that the widest point is about a third the way back.

Adding some wheels, removing the sharp edges (I probably should have elongated the back JUST a fraction)...