[DeTomaso] I've got to get going on my restoration

JDeRyke at aol.com JDeRyke at aol.com
Tue Aug 3 15:10:18 EDT 2010


In a message dated 8/3/10 5:34:37 AM, rob at dumoulins.net writes:

> Gudmund stated that hot air was exiting his vents at 50-60 mph.  If that 
> is so, there is a low pressure area pulling engine air out like a venturi 
> as the air passes along the side of the car.
> 
It is so; several of the Swedish members did an airflow tuft study using a 
camera car a few years ago and air could be seen exiting the scoops (or 
openings if the window glass is out). More likely, the air flow UNDER the car is 
being drawn up and out the rear window opening. The Pantera, Ferrari Boxer &
 other similar decklid design is well known for creating a huge low- 
pressure area behind the roof, and some of the exiting hot air from below is going 
out the side openings, since the decklid 'window' is a slight restriction 
relative to the entire underside of the body. 

At some speed, the 4" thick boundary layer along the sides of the car thins 
enough so side-scoops finally do get a 'bite' and start feeding air into 
the area against the pressure from airflow under & out. I suspect this point 
is around 150 mph since thats the point M.D. had one rip right out of his SS 
car, also taking the chrome frame with it. This is a not-well-understood 
area of an obsolete car, so there are lots of guesses; some wind tunnel testing 
would clarify many questions. Sadly, while there's lots of interest in the 
results, no one wants to do the actual work.... I checked into using the A2 
tunnel in N Carolina 5 yrs ago, but no local POCA members could be found to 
do the testing. Thats a 2800 mile one-way trip for me, so on a retired 
income, it ain't gonna happen. FWIW- J DeRyke



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