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Old 12-30-2013, 05:40 PM   #21 (permalink)
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Originally Posted by Cd View Post
I have read in the past that the fins on cars such as those in the above image resulted in large vortices. Much larger than if none were present.
Want to chime in on this Aerhead ?
We would want to take the cars on a case specific basis I suppose.
Alfa Romeo got some tasty Cds with their 3-car B.A.T.series of show cars.
Chrysler did some tests and reported directional stability benefits attributed to fins.The 'fin'/wing on the Daytona does add up to 36% added drag in strong crosswind.
Kamm was seemingly obsessed with fins and put them on all his own cars,up to his last project for the DKW/Audi notchback of the 1960s.
Some of the Citroens,due to their forward weight bias,are so stable without fins,that one may cruise all day at 127-mph with nary a care.
Morelli put them 'under' his banana car behind the rear wheels.
Ford claimed that the dorsal fin on their Probe-V,Cd 0.137 concept helped it achieve outstanding directional stability in gusts and crosswinds.
We could go on forever.
The fin was a 'styling' gimmick for the most part.
When used as a palliative for stability issues,aerodynamicists figured that the car's body could be reconfigured so as not to create the situations needing 'fixing' with fins, as Lamborghini is doing today.

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