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Old 06-23-2021, 02:01 PM   #14 (permalink)
aerohead
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Quote:
Originally Posted by JulianEdgar View Post
I am going to post some aero cars - not every day, as the thread name implies, but whenever I feel like it. (Unlike the Random Aero Cars thread, I will always try to provide some measured data.)

All the cars are covered in my book - A Century Of Car Aerodynamics (link below).

Today's car - the 1983 Fiat Uno.



The Uno was a low-cost car made in huge numbers over 8 million were built. Most interesting from an aerodynamics perspective, it was a small hatch. The smaller the car, the harder it is to achieve a low Cd. And since a hatch will always have a large wake, with that shape we have another aerodynamic negative. But Fiat took great care to optimise the aerodynamics especially drag at a time when few manufacturers were bothering much about the aerodynamics of their cheapest cars.

Cd was 0.34 (standard car), 0.33 (economy special) and 0.30 (Turbo). Lift figures were also good - and across the whole range of yaw angles.

One might want to provide some context with respect to a qualifying adjective as 'smaller'.
We know from verisimilitude that there exists no prohibition from 'shrinking' the proportions of a very low drag vehicle, creating a 'smaller' vehicle of identical Cd.
An example would be Morelli, who took a small, 1976 FIAT of Cd 0.44, and turned it into Cd 0.23.
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