Date: Sun, 29 Jul 2007 21:26:48 +1200
Reply-To: Andrew Grebneff <andrew.grebneff@STONEBOW.OTAGO.AC.NZ>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Andrew Grebneff <andrew.grebneff@STONEBOW.OTAGO.AC.NZ>
Subject: Re: Some aerodynamic ideas..
In-Reply-To: <001e01c7d191$e927a0e0$2219e442@dhanson>
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> The Vanagon is exactly wrong for aero-efficiency...Actually, if it were a
>perfect square rather than a rectangle, it would be worse, but..
And the Poms call them "wedges"... guess they don't know what the word means.
> So, some of the things that could be done for better slippery...
>
> A front splitter would be about the easiest thing of all. A splitter is
>just a 'shelf', a flat projection off the front, parallel to the ground. In
>essense a splitter fools the air into thinking the vehicle is much longer by
>stacking up air on the top of the splitter. A splitter would also reduce
>the airflow under the van. Since we probably wouldn't be looking for
>'downforce', limiting the flow under the van would reduce the turbulence
>there somewhat.
> Flush windows would be a help also, and do-able.
I've seen a Bay with dark-tinted ?plexiglas mounted over the
sidewindows... sort of looked like a mid90s Toyota Liteace. The
sheets covered the pillars as well. Looked good.
T3s don't have flush windows, but they're less-sunken than a Bay's.
No reason a T3 couldn't be so treated, but it would mean drilling
holes in the bodywork... and even a minor airleak between body &
sheet would probably cause whistling at speed. If I wasn't so
chronically short of money (and if my bus was close to being on the
road) I'd consider it myself.
>However, the square
>front corners of the windscreen probably starts turbulence there right there
>that continues for "a mile" behind the van
That's unavoidable with a true van. Ths closest to aerodynamic I can
think of in vanlike vehicles is Toyota's midengined "egg" Estima
(Previa/Tarago) and possibly the competition, Nissan's cynical
Serena. True vans, including the awful space-compromised FWD
offerings from Europe, generally have flattish windshields with
strong corners at the A-pillars (eg Mercedes/Freightliner/Dodge/VW
Sprinter/LT, Ford Transit, Fiat Ducato, Renault & Pugeot
competition). I doubt the longer noses of these vehicles give any
aerodynamic advantage.
>, so back to the "Entry" the
>nose...the splitter.. Raking back the front windshield would be rather
>effective also, but beyond most of us, what with the doors right there, etc.
The T3 already has a fairly-well-raked windshield.
> Smooth wheel covers would be an easy improvement..Like those old Moon
>hubcaps..
Ugly. And of course bad for brake-cooling. Ever seen a supercar with
smooth wheels, much less hubcaps?
>Mirrors that didn't stick way out would help some also.
Again, unavoidable. You need big mirrors for proper rear-vision. Best
you can do is fit mirrors with a deeper-dished housing, say
Japanese-market Hilux.
> But, given the shape of a van, the job of significantly improving it's
>aerodynamic coefficient of drag would be....daunting..
That's vans... the idea of maximized interior space is
diametrically-opposed to the ideals for aerodynamics.
As to the rear, perhaps a splitter under the tail & a
properly-designed roof-spoiler eg Projektzwo T3 or Mazda's 90s Bongo
(also sold as Ford Spectron). Not that either spoiler has been
tunnel-tested... though I have considered widening & fitting a Bongo
item.
--
Andrew Grebneff
Dunedin
New Zealand
Fossil preparator
<andrew.grebneff@stonebow.otago.ac.nz>
Seashell, Macintosh, VW/Toyota van nut