Re: alfa-digest V9 #406

[George Graves <gmgraves@xxxxxxxxxxx>]

It's a guy's name. Some German aerodynamicist from the 1930's, IIRC. At 
the time, it was believed that a tapered tail which came to a long 
point was best for aerodynamics because it 'eased' the slip stream back 
together. Kamm did some wind tunnel studies which showed that this 
shape caused extreme turbulence and that the low pressure area formed 
on top of the sloping back actually caused MORE drag, not less. He 
found that by truncating the tail (according to some area rule he 
worked out mathematically) and adding a small lip to the top of the 
truncation, that this low pressure area and the turbulence that caused 
it could be "spoiled." Hence the term 'Kamm Spoiler.' It wasn't really 
until the late '50's and early '60's when race cars started to exceed 
150 mph on a regular basis, that Kamm's findings started to have any 
real effect on race car design. The Giulia TZ was certainly the first 
Alfa to use these principles, but  the early mid-engined V-6 Ferrari 
246 SP road-racers from about 1960-61 was the first serious use of the 
'Kamm Effect' that I can recall. After that cars like the Shelby Cobra 
Coupe, the GT-40, the Ferrari P2, P3, and P4 all relied heavily on the 
Kamm Effect. Of course, many road-going cars aped the Kamm features as 
styling gimmicks, including the 1963-64 Ferrari Lusso, The 1967-69 
Shelby GT350 and 500, The already mentioned Toronado, The Lotus Esprit, 
the Alfa spider from 1971 to the late '80's as well as the Alfetta GTV, 
GTV-6, along with many others. As to whether any of these styling 
tricks actually did anything aerodynamically is a matter for 
conjecture, because without wind tunnel tests, its almost impossible to 
know.

George Graves
'86 GTV-6 3.0S



On Friday, April 11, 2003, at 09:20 AM, alfa-digest wrote:


> Date: Fri, 11 Apr 2003 07:07:29 -0700 (PDT)
> From: Russ Tine <rtalfa@domain.elided>
> Subject: Kamm?
>
> I was reading the current issue of Car Collector Magazine, and they 
> had an article about the Olds Toronado. They refered to it as being a 
> Kamm-back. I know that my spider is a Kamm-tail, as opposed to a round 
> tail, but I was curious about the origin of "Kamm". Anyone have any 
> ideas? Regards,Russ Tine75 spider87 milano
> Yahoo! Tax Center - File online, calculators, forms, and more
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