sheesh!

I posted info about this a couple of months ago, wasn't anyone 
listening?

:)

Alistair

'82 westy, diesel converted to gas in '94

http://www.members.shaw.ca/albell/

On 18-Oct-04, at 5:29 AM, jimt wrote:

> The formula for drag through a medium is:
>
> Drag = 1/2 D x Cd x A x Vsquared
>
> D = density of medium (in this case air)
> Cd= drag coefficient (slipperiness) (need to know this value or get a 
> wind
> tunnel)
> A = the frontal area
> V = velocity
>
> Note where the coefficient and area are in the equation.
> Then comes the kicker.  Note that velocity gets squared.
> With squaring there is always a point where the squared item goes from
> insignificant to very significant.  In this case the velocity we are
> traveling at.
>
> This number is then added to the rolling drag. Computed from weight 
> volume
> and resistance items.  Then you get your total drag or resistance to
> movement.
>
> 0.00255754    1    16    1    0.04
> 0.00255754    0.5    30    1    0.04
>
> Above shows that a flat box surface presented in direct resistance 
> comes up
> with the same value as the lower slippery vehicle that has about twice 
> the
> area presented.
>
> ����������������������������������������
> jimt
> Planned insanity is best.
> Remember that sanity is optional.
> http://www.tactical-bus.info (tech info)
> http://www.westydriver.com
>
>
>
> On 10/18/04 5:39 AM, "Eric Zeno" <vw4x4@FYI.NET> wrote:
>
>> Aerodynamically everybody seems to be missing one thing.
>> If I have a very unslippery vehicle with a coefficient of 1 (flat 
>> surface)
>> and a slippery vehicle of .5 and the surface area in question on the 
>> .5
>> vehicle is 3 times the area of the vehicle with a rating of 1,  the .5
>> vehicle is much higher in resistance than the vehicle with a rating 
>> of 1.
>>
>>
>>        Interesting!     By what critera is the surface area measured?
>> I've never seen spec's
>> on this.                                      Eric
>>
>>
>> jimt wrote:
>>
>>> On 10/17/04 8:53 PM, "Stan Wilder" <wilden1-1@SBCGLOBAL.NET> wrote:
>>>
>>>
>>>
>>>> With less than 100 hp the dream of 100 in a Vanagon is just a dream 
>>>> unless
>>>> you drive off cliff and read your airspeed indicator on the way 
>>>> down.
>>>> I think Bruce just dropped the hammer on his hybrid toy to see how
>>>> everything behaved and reached that 101 as part of the test but 
>>>> that brings
>>>> up the speedometer error that is about 10% and that means he was 
>>>> only doing
>>>> 92 mph. Well within reasonable speeds for Texas Highways for all 
>>>> Pickup
>>>> trucks, SUVs, MPVs, 18 wheelers, and Rice Rockets of both the two 
>>>> and four
>>>> wheel varieties.
>>>>
>>>> Stan Wilder
>>>> High Performance Ceramic Coatings
>>>> www.engineceramics.com
>>>>
>>>>
>>> Last year after a proper breakin on my subie mod I took it out on 
>>> the flats
>>> on i70 towards kansas.  Took it up to just under 6k on the tach.  At 
>>> that
>>> speed my speedo is definitely off by very close to 15 percent.  
>>> (only goes
>>> to 85). However 5.8 x 18 is comfortably (uncomfortably) over 100mph. 
>>> Havent
>>> done it since and don�t plan on it.  Even at a moderate 80mph a 
>>> crosswind is
>>> not nice in a vanagon or any slabsided vehicle.  For a regular 
>>> vanagon to
>>> hit those speeds is right at the cutoff.  The subie electronic 
>>> cutout is at
>>> about 6.2k  the vanagon electronics cuts out at about 5.8k plus or 
>>> minus a
>>> little.  I am told that the last couple years of the vanagon the ecu 
>>> cutout
>>> at 6k but no change was made to part numbers.
>>>
>>> Aerodynamically everybody seems to be missing one thing.
>>> If I have a very unslippery vehicle with a coefficient of 1 (flat 
>>> surface)
>>> and a slippery vehicle of .5 and the surface area in question on the 
>>> .5
>>> vehicle is 3 times the area of the vehicle with a rating of 1,  the 
>>> .5
>>> vehicle is much higher in resistance than the vehicle with a rating 
>>> of 1.
>>>
>>>
>
> ����������������������������������������
> jimt
> Planned insanity is best.
> Remember that sanity is optional.
> http://www.tactical-bus.info (tech info)
> http://www.westydriver.com
>