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Old 10-08-2014, 06:21 PM   #144 (permalink)
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Originally Posted by NeilBlanchard View Post
The Darko tunnel is not very large, is it? The sectional size, I mean. This makes having the "calibration" of the Prius all the more important.
Yes,it's not 'large' inside.When we get the video up and running you'll see.
And I just re-visited the article about the Chevy VOLT,where GM's Bob Boniface says the Prius was measured at Cd 0.30 at GM,Ford,and Chrysler.So we now have an even bigger can of worms,considering that the Volt scored Cd 0.28 at both GM and A2,and A2 gave the Prius Cd 0.26.
Hucho mentioned that a test vehicle should be no more than 5% of the test section cross sectional area.Hucho also says that the Pininfarina tunnel,quite small compared to Lockheed and GM,nevertheless develops quite similar measurements.
The curved-wall construction of A2 and Darko is supposed to compensate for boundary layer growth and 'choking',providing a uniform pressure/velocity across the area.
As time passes,and we have more cars to compare,we'll be able to better correlate data from one tunnel to the next.
I have no reservations about Darko's facility.I wish my mods could be quick on-and-off,for A-B-A testing though.If we'd had a bone stock T-100 to throw in the tunnel,either before or after the Spirit of,we'd have some valuable info to chew on.Something to think about for the future.
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