<VV> Louvers and airflow

[Ken Wildman]

Ned:

Years ago I spent several hours talking to a visitor to my Ultra Van at a
Corvair National.  He was an engineer at GM and worked primarily in
aerodynamics with thousands of hours dealing with wind-tunnel studies.

I asked him about the question of "scoops" for the primary air intake on
Ultra.  Some swear by them, some swear at them.   :)  My own experience,
while the head-temp. gauge was still working was cooler running with the
scoop.  The present owner of my old coach, Ed Lindsey, removed the scoop.
He also did a lot of clean-up in the engine compartment and I think replaced
the engine.

The engineer said, you just can't predict/calculate aerodynamic effects.
His suggestion was to do exactly what you had done.  Tufts of yarn attached
along the sides.  Drive on the highway with a "chase" car looking at the
tufts.  If the scoop was effective the tufts near the opening would be drawn
in.

Since I was satisfied that my coach ran at good temperatures I never went
through the test myself.

Ken Wildman
'66 Corsa-ized cvt, 140/f
'66 Monza Sedan, 110/PG
ex '68 Ultra Van, 110/PG

On Tue, Nov 30, 2010 at 12:17 AM, <AeroNed at aol.com> wrote:

> James,
>
> I did a "wind tunnel test" on an EM and a LM coupe with tuffs (little
> strips of yarn) all over the cars for the PW. The tuffs show airflow and
> areas
> where the air is separated from the surface. The LM vents has good airflow
> on only the outboard half to 2/3s of the vent. The Stinger vents are in a
> "good" airflow area, not a high pressure area. Having the doors open
> instantly  give a high pressure.
>
> BTW The Performance Workshop in Indy is a great place to hear lots of cool
> stuff about Corvairs, it's not just about racing. Yup, that was a plug.
>
> Ned
>
>
> In a message dated 11/29/2010 7:25:53 A.M. Central Standard Time,
> ricebugg at mtco.com writes:
>
> All:  As an employee of Caterpilar's Service department many  many years
> ago,
> I had access to tempertute sticks/crayons.  I had a LM  with a hopped up
> Turbo, and on occasion noted the engine compartment  temperture.  So one
> hot
> 90+ degree day, before leaving work, I marked  up the engine sheet metal
> and
> chassis rails and drove it.  The color  change of the markings indicated
> about 275 degs in several places with cyl  hd temp on the guage of about
> 400
> deg. One of the reasons I normally had  the spare and tools in the trunk.
>
> Also, again many many years ago Dave  Newell showed me drawings from
> Chevrolet of the air presure on EM's deck  lid.  As I remember it, at
> normal
> higway speed, the high pressur area,  and hence the source of air flow, was
> right over the louvers.
>
> Also  note the air flaps location on the Yenko Stinger.  According to  one
> source, Yenko tested the LM in a wind tunnel to determine where the  high
> pressure area was "at speed" and put the flaps there.  Of course,  the "at
> speed" speed was a lot higher than any of us would try on the  street
> right?!
>
> Historically Yours,
> James  Rice
>
>
>
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