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Old 11-30-2009, 06:43 PM   #154 (permalink)
MetroMPG
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Join Date: Nov 2007
Location: 1000 Islands, Ontario, Canada
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Blackfly - '98 Geo Metro
Team Metro
Last 3: 70.09 mpg (US)

MPGiata - '90 Mazda Miata
90 day: 54.46 mpg (US)

Even Fancier Metro - '14 Mitsubishi Mirage top spec
90 day: 70.75 mpg (US)

Appliance car Mirage - '14 Mitsubishi Mirage ES (base)
90 day: 62.14 mpg (US)
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Tuft testing round 2: sides & top

Oh, yeah - a varnished cedar strip boat tail would look fantastic on a black car!

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I get such a kick out of tuft testing. I could watch these videos over and over.



Top side observations: I can report that the tufts on the top lie very still. Makes me wonder how much more angle/curvature I could get away with. (Wish I had all the time - and warmer weather - in the world to keep on working on this!)



Details of camera set-up, above:
  • The white line across the side of the car is the USB cable for the web cam, which is the little pod duct taped to the end of the "boom" (aluminum tube).
  • I spiral wrapped the USB cable up the boom to alter its aero properties (minimize drag force)! Did it work? Who knows. You sometimes see this sprial treatment on smoke stacks.
  • The white line from the cam to the roof of the car just is some string, pulled taut to tension the boom and minimize bouncing.
  • The boom is attached (duct taped) to the aluminum tube frame of the boat tail. I cut a pair of flaps in the cardboard, top and bottom to access the tubes inside (you can see the bottom flap still open).


Driver's side observations: you can see for yourself even from this screen capture that there's more flutter - turbulence - on the side, increasing toward the bottom. No surprise there - probably the effect of the rear wheel.

Below: camera setup for the side shot. It sticks out about 3 feet from the side.



Next: I decided that since I've got this all set up already, before I pull off the tufts I'm going to CAD up a mini-boattail for behind the wheel, just to see what it does. (Cd will be happy to read that!)

Once I've done that (tomorrow, maybe), I'll put the tuft testing clips together into one video and post it.

THEN I'll watch for a good day to do the highway speed A-B-A on the entire boat tail.
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Project MPGiata! Mods for getting 50+ MPG from a 1990 Miata
Honda mods: Ecomodding my $800 Honda Fit 5-speed beater
Mitsu mods: 70 MPG in my ecomodded, dirt cheap, 3-cylinder Mirage.
Ecodriving test: Manual vs. automatic transmission MPG showdown



EcoModder
has launched a forum for the efficient new Mitsubishi Mirage
www.MetroMPG.com - fuel efficiency info for Geo Metro owners
www.ForkenSwift.com - electric car conversion on a beer budget
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