View Single Post
Old 04-22-2009, 11:23 PM   #36 (permalink)
MetroMPG
Batman Junior
 
MetroMPG's Avatar
 
Join Date: Nov 2007
Location: 1000 Islands, Ontario, Canada
Posts: 22,534

Blackfly - '98 Geo Metro
Team Metro
Last 3: 70.09 mpg (US)

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

Appliance car Mirage - '14 Mitsubishi Mirage ES (base)
90 day: 57.73 mpg (US)
Thanks: 4,082
Thanked 6,979 Times in 3,614 Posts
Wow. Looks impressive.

Any chance you can tuft test it? That will tell you for sure what's going on.

I hate to "armchair design" someone else's work, but I have a sneaking suspicion that the slope of the top may be a bit steep - you need to ensure you've got flow reattachment (it would have detached at the trailing edge of the roof) before you can start your tapering.

While the shape of the sides may be OK, if the angle on the top and bottom surfaces is too steep, vortices may also be forming there. The sharp angle at the transition from "side" to "top" (and "bottom") would contribute to that effect.

Tuft testing will tell all!
__________________
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
  Reply With Quote
The Following User Says Thank You to MetroMPG For This Useful Post:
HHOTDI (01-18-2013)