Date: Sat, 27 Sep 2008 11:07:55 -0700
Reply-To: Roger Whittaker <rogerwhitt1@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Roger Whittaker <rogerwhitt1@GMAIL.COM>
Subject: Re: Aerodynamics and the Westie luggage rack, etc..
In-Reply-To: <0c6401c920ca$a21a1230$6401a8c0@PROSPERITY>
Content-Type: text/plain; charset=ISO-8859-1
dear all
yes scott is correct ... presently though i am not set up for any sort of
fiberglass repair or production ...
indeed today moving --
then moving again in three weeks to another place once it is ready -
that will be an apartment and fiberglass repairs are frowned upon with in
the building
likely sometime in the coming year we will get more settled and be in a
place that allows us to do other stuff
it is on the list of stuff to do ...
yours
On Sat, Sep 27, 2008 at 10:58 AM, Scott Daniel - Turbovans <
scottdaniel@turbovans.com> wrote:
> we really should use your front aero westy roof rack replacement piece to
> make a mold,
> then make fiberglass reproductions of what you have there Roger.
>
> ----- Original Message ----- From: "Roger Whittaker" <
> rogerwhitt1@GMAIL.COM>
> To: <vanagon@GERRY.VANAGON.COM>
> Sent: Friday, September 26, 2008 11:31 PM
> Subject: Re: Aerodynamics and the Westie luggage rack, etc..
>
>
>
> dear fronts piece wanters
>>
>> you guys all laugh at my millage #'s and say they are untrue ...
>> oh well what ever --
>> i know the 1.6 TD achieved 35-38 miles to the gallon and
>> i have yet to take a significantly long journey with the new 1.9 TD that
>> replaced that tired little motor
>> and i know you also laugh at my speed claims ...
>> yet i just re-listened to the voice diary and in one point of the trip i
>> had forgotten to shut off the digital recorder
>> it captured a conversation between wife and i regarding keeping speed at
>> or
>> around 75 MPH
>> so i would not get a ticket --
>> several times on very long stretches of # 10 East bound
>> i had to tune it down a little as i creeping into the 90MPH zone
>>
>> doubt-laugh- scorn - no worries
>> it was simply my experiance ...
>> with that nifty fronts piece in place on our
>> 1989 5 Speed California Turbo Diesel
>> yours
>>
>> On Fri, Sep 26, 2008 at 10:18 PM, Andrew Grebneff <goose1047@gmail.com
>> >wrote:
>>
>> On Fri, Sep 26, 2008 at 10:31 PM, Don Hanson <dhanson@gorge.net> wrote:
>>> > I did some low budget research about aerodynamics, read up on all the
>>> > sources I could find, etc. So I know a little, but I certainly can't
>>> spout
>>> > data or numbers, just general principals.
>>>
>>>
>>> Aerodynamics really only come into play at above 110kmh (~70mph).The
>>> vehicle may not feel as though it's run into a wall above that speed,
>>> but your fuel bill will suggest otherwise, almost no matter what
>>> vehicle (figure that phrase out if you can).
>>>
>>> That's probably why the top speed of a 25hp (the so-called "36hp"
>>> engine) Split will top out at 110kmh, empty ot with a tonne of cargo.
>>>
>>> Modern vans still have external gutters, but that's because they have
>>> a large roof area and concealed gutters couldn't cope with decent
>>> rain... and of course it would be expensive (anda rust trap) to put
>>> concealed full-length gutters into one.
>>>
>>> The rear of a vehicle is important in drag calculations. A vehicle
>>> with a sloping back roof and tail (eg a real Beetle) will have a poor
>>> drag coefficient, because there is no separation of airflow over the
>>> vehicle from the air behind it, causing a relarive low-pressure area
>>> behind the entire rear surface of the vehicle, from roof high-point to
>>> bumper. That's why the more aerodynamic cars have a sharp lip on the
>>> back of the trunk edge, and probably why T3s have a very good CD (and
>>> a T2 has a better CD than an E-Type Jaguar)...
>>>
>>> Of course, for a given shape, the larger the frontal area, the more
>>> overall drag there will be, as you are trying to push a larger surface
>>> through the air (which is a fluid). Take a T3 and double its size in
>>> all dmensions and you'd be increasing the drag 4 times. So take this
>>> into account if you're widening your bus by 20cm and want to retain
>>> what we laughingly call its fuel-economy.
>>>
>>> ... the rear lip causes separation of the airflow over the car from
>>> the turbulent air trail behind, reducing overall drag. It probably
>>> also creates a little downforce at the rear, but it wouldn't be
>>> significant.
>>>
>>> Putting an airdam on the front, IF the dam is windtunnel-tested... and
>>> believe me, most are NOT), can decrease drag by reducing the amount of
>>> air going under the car (which also, by being compressed as it paasses
>>> under the car, which is acting as one side of a venturi, produces
>>> lift, which is most noticable at the front). However the airdam itself
>>> adds frontal area, which increases drag... so a properly-designed
>>> airdam is a compromise.
>>>
>>> Rear spoilers are supposed to work by forcing air upward as it passes
>>> over the tail, which results in downpressure on the car's tail. That
>>> is the ideal... again, as with airdams, most "spoilers" are just
>>> eyecandy and have only one effect... increased drag.
>>>
>>> Sideskirts are only functional on cars utilizing radical
>>> "ground-effect" for downforce eg the banned Formula 1 cars.
>>> On a road car there is nothing to suck air out from under the car, so
>>> skirts have nothing but esthetic function... and are one more thing to
>>> have to repair (as well as being rust-traps, as are most plastic
>>> addons eg spoilers).
>>>
>>> Just as well that parentheses don't cause rust, or this mess
>>>
>>> age
>>>
>>> would be fall in g t o
>>>
>>> pi
>>>
>>>
>>> e
>>>
>>>
>>> c
>>>
>>>
>>>
>>>
>>> e
>>>
>>>
>>>
>>>
>>> s
>>>
>>>
>>>
>>> .
>>>
>>>
>>> .
>>>
>>>
>>> .
>>>
>>>
>>> --
>>> Andrew Grebneff
>>> Dunedin, New Zealand
>>> Fossil preparator
>>> Mollusc, Toyota & VW van nut
>>> Temporarily in Calgary, AB, Canada
>>> <goose1047@gmail.com>
>>>
>>>
>>
>>
>> --
>> roger w
>> There are two kinds of jobs in the world:
>> Picking up garbage and telling people things.
>> Successful people do both, with the same good attitude. (riw)
>> ----------------------------------------------------------
>> Explore printed work at: http://www.prliving.ca/
>> View the growing list of video work at:
>> http://revver.com/find/video/?query=LastonLastof&search_on=owners
>> and ... older work at
>> http://video.google.com/videoplay?docid=-7135104650374818257
>> http://video.google.com/videoplay?docid=3259745150182742364
>>
>
>
--
roger w
There are two kinds of jobs in the world:
Picking up garbage and telling people things.
Successful people do both, with the same good attitude. (riw)
----------------------------------------------------------
Explore printed work at: http://www.prliving.ca/
View the growing list of video work at:
http://revver.com/find/video/?query=LastonLastof&search_on=owners
and ... older work at
http://video.google.com/videoplay?docid=-7135104650374818257
http://video.google.com/videoplay?docid=3259745150182742364
|