One final thought on an extreme FE car. We should all keep in mind the fact that inexpensive, high FE vehicles have already been built and sold successfully, such as the WV Lupo.
Yes, that's true. The Lupo has a Cd of 0.29, and is capable of better than 3L/100km. Think of what it could do with a Cd of 0.15.
There is no magic to it. The easy, affordable way to big FE numbers is low tech rather than high tech. Nobody will buy an expensive vehicle that is so aerodynamic that it's non-ergonomic.
Again, it depends on the price of fuel. If price of fuel outweighs the benefits of ergonomics AND styling, then really good Cd*A figures will make perfect sense. And I suspect that once cars like this are common, the stigma against having one will be removed.
It's like recumbants versus uprights. It's only because the first mover was an upright that people might laugh at recumbants, just like people used to think that those with mobile phones were vain and pretentious. Once something becomes commonplace, the stigma gets removed. Provided that a car fits the required number of passengers in, can accelerate to a given speed, is safe and not difficult to manufacture, then it's the same thing. I don't see why the aerodynamic shape has to be expensive or high-tech for that matter.
Consider that the T77a was manufactured in the 1930s with Cd lower than cars today. Consider the curved surfaces of most new cars, and the possibility of using plastic panels. I.e. It shouldn't be difficult or expensive to make a boattail, even if it is dead space, worst case. But there is this false dichotomy that says econo=small box.
I wonder if (part of) the reason for this is simply price discrimination.
If people were given the option between a heavy "luxury" car and a cheaper, lighter FE car that did almost all the same things, of a similar size, might everyone not buy the cheaper car? I think this might be worth a thread.
1) light weight
2) reasonably low Cd / low A,
3) a matched (small) efficient engine, whether gas electric or diesel
4) efficient accessories.
Yes. I'd also add "tall enough gearing", and perhaps automatic engine-off technology (forgot what it's called) if it's reasonably priced.
Also, there is the 3-box design legacy to take into account. Almost all the design out there is evolutionary rather than revolutionary. This is unfortunate, because rather than asking "How can I take the most FE design possible and make it practical?", they go from the other end and ask "How can I take an existing car and tweak it to make it FE?"
The gulf between what is possible through a revolutionary design and what can be attained by an evolutionary process is immense, as is the time it can take.
To get an idea of the problems associated with evolutionary design, look at this.
We have the understanding to design for ultra low Cd. We know the basics of what we need to have in a car - room for passengers, room for luggage, an engine, visibility, etc. If we realize the coming need for improved FE now, then it is possible to have a total rethink of everything with the knowledge that fuel concerns will trump most other stuff in future.
In addition, such a vehicle will open up other possibilities. For example, if your relatives live a few hours away, going to see them is less of an issue if the cost is minimal. Going to far off places by car becomes easier if it costs next to nothing.
Much of the weight in today's cars is useless fluff added to the interior. Many new cars are loaded with 400-600 pounds of unnessessary sound deadener, used as an excuse to inflate the price of the vehicle and compensate for the road noise and improper weight districution caused by a poorly engineered design.
Take note that many of the classic musclecars weigh hundreds of pounds less than the 'lightweight' BMW Z4s and Porsche Boxters of today.
Just recently, two cops in my city got into a wreck. The dashboard in their Crown Vic broke and fell onto their legs, snapping their bones like twigs.
Cars are getting bigger on the outside, but smaller on the inside. I sat in a rented new Chrysler "crossover" SUV in Florida a few months ago. It had less room inside than my wife's Corolla. So much for progress.
Capitalism: The cream rises. Socialism: The scum rises.
I had a search around for stuff on aerodynamics. It led me on a search for airplanes, among which the Piaggio P180 and Mike Arnold's AR-5 stood out. It's definitely worth a look at to get a glimpse of where to go to from here.
Be careful withthe airplane designs. They ioperate on the principle of laminar flow, as opposed to turbulent flow. Whereas our skies are often free of debris, our roads are an entirely different matter.
A small scratch or dent, even if difficult or impossible to see with the naked eye, is all that is needed to trip the laminar flow into turbulent flow, and all your aero benefits in regard to efficiency go to crap.
For a car, I'd recommend staying within the domain of turbulent flow and try to minimize drag from there. That means a teardrop shape, as opposed to a giant penis shape.
There is a reason solar cars, designed for low drag, do not adopt laminar flow designs as airplanes do.
If only there were a way to prevent nicks, cracks, rust, and warping from ever occuring. Then laminar flow might become useful in cars.