Kamm tails and the Giulia

["Daegrigg (Don)" <daegrigg@xxxxxxxxxxx>]

Most of us think spider when we hear Kamm tail and aerodynamics.  'Truth is
the "boxy" Giulia sedan in all its variants had the lowest drag coefficient
at 0.32 of its time and held that title for production cars well into the
1980s.

Don

----- Original Message -----
From: Todd Schinell <alfatodd@domain.elided>
To: <alfa@domain.elided>
Sent: Monday, April 14, 2003 10:43 AM
Subject: Re: Kamm tails and drag


> I noticed the VW experimental car which gets 300+ mpg and has a drag
> coefficient of 0.159 also has a Kamm tail.  The most aerodynamic
production
> car, the Honda Insight comparitively has a 0.26 coefficient.  You can see
> the Kamm tail in the 3rd image down here:
> http://www.benerridge.freeserve.co.uk/economy.htm
>
> ----- Original Message -----
> From: "C M Smith" <cmsmith@domain.elided>
> To: <alfa@domain.elided>
> Sent: Saturday, April 12, 2003 10:56 PM
> Subject: Kamm tails and drag
>
>
> > I thought the Kamm tail effect resulted from the fact that the Kamm tail
> > caused the tail to drag a blob of turbulent air behind the tail that
> > approximated the airflow of the long tailed tear drop shape previously
> > thought to be ideal, which reduced skin drag due to air to air friction
> > being lower than air to bodywork friction. The increase in efficiency is
> > due to the reduction in skin drag resulting from the chopped tail and
the
> > fact that air to air friction is lower than air to bodywork friction of
> the
> > long tail version. Certainly Porsche experimented successfully with the
> > long tail Le Mans design that also had a Kamm tail but further back
along
> > the ideal teardrop shape. I do not think that turbulence associated with
> > tear drop shape could be a factor since the tear drop has very little
> > turbulence associated with it. Skin drag is a huge factor at high
speeds.
> > Turbulence drag is a problem at low speeds also, hence the amount of
money
> > devoted to reducing turbulence drag from door mirrors and rain gutters
to
> > cite two mundane examples.
> >
> > cheers etc
> > Michael Smith
> > White 1991 164L
> > Original owner
> > --
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