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Old 09-28-2012, 08:07 PM   #567 (permalink)
MetroMPG
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Location: 1000 Islands, Ontario, Canada
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Blackfly - '98 Geo Metro
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Last 3: 70.09 mpg (US)

MPGiata - '90 Mazda Miata
90 day: 52.71 mpg (US)

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90 day: 70.75 mpg (US)

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Woohoo! Tuft testing videos! Short but tantalizing....

I think the tufts are doing pretty much what they "should" be doing, but dang, those tufts are looooong! And therfore kinda heavy.

The "25 mph is OK for tuft testing" rule apparently assumes short, light tufts. Never thought about that before!

So going a little faster would probably help clear things up a bit, just to make sure the air is overcoming gravity's pull on the wooly bits.

That said, I think you can still make some conclusions that will hold up in a higher speed test:
  • Up front, it's normal to see downward flow on the sides of the car aft of the front wheel, since there's high pressure at the windshield and lots of flow coming down around the A-pillar.
  • The "hanging" tufts on the rocker panel are probably in separated flow behind the front wheel. (or at least very turbulent flow)
  • Looks like you've got attached flow on the top of the tail, right to the tip - congrats!
  • Upper sides of the tail look decent too.
  • Looks like separation on the bottom of the tail though, at least around that single row of tufts close to the end. (Put a couple more tuft rows further forward for tomorrow's video!)
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