Quote:
Originally Posted by cosmick
That triples the total drag all by itself.
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Quote:
Originally Posted by freebeard
Citation needed.
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Complex question with no easy side-by-side comparisons... but in the ballpark. CdA is Cd * A and you can reduce both those factors substantially for an 'inline' design.
For the very low speeds cars travel at, the optimal fineness ratio is probably somewhere in the 1:4 to 1:5 range (form drag being somewhat dominant over skin drag), which is much easier to achieve in reasonable length if the vehicle isn't as wide - just take a look at how much length a good boat-tail adds to a hatchback. With an inline design you can achieve a (seemingly) ridiculously low Cd and still have something that doesn't require a special parking space to fit the tail.
The frontal area may not quite go down by half, though you can get close to it - and that's quite a substantial factor.
Multiply both of those together, and a ballpark factor of 3 isn't unreasonable. It would only require a 42.5% reduction in each of Cd and A, for example, both of which are quite achievable.
A local example of an 'inline' design:
Trev (two-seater renewable energy vehicle) and there are even reasonably comprehensive build instructions at
Trevipedia . Though I can't find any Cd or CdA info, it apparently achieves 62 Wh/km (6.2 kWh/100km) at 80-90 kph cruising, which isn't too shabby compared with 'side-by-side' EVs currently on the market.
(Yes, I know this has been linked in this thread before, but it was a while back and it's relevant to the discussion)