Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post - Video: Illustrating the Vast Importance of Aerodynamics (open hatchback experiment)

MetroMPG · 12-14-2007, 12:37 PM

I'm not surprised you saw such a big difference with having the hatch open at low speeds.

Based on miscellaneous comments I read all over the web, people often seem to think that aero losses "magically" come into play only above some arbitrary speed.

Even at just 20 mph, 1/3 of the total power (about 1.2 hp) required to move a Metro goes to overcoming aero losses. 1/5 of the power at 15 mph. (Based a RR & aero loss spreadsheet, with all the usual formulas).

12-14-2007, 12:37 PM	#2 (permalink)
MetroMPG Batman Junior 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	I'm not surprised you saw such a big difference with having the hatch open at low speeds. Based on miscellaneous comments I read all over the web, people often seem to think that aero losses "magically" come into play only above some arbitrary speed. Even at just 20 mph, 1/3 of the total power (about 1.2 hp) required to move a Metro goes to overcoming aero losses. 1/5 of the power at 15 mph. (Based a RR & aero loss spreadsheet, with all the usual formulas). __________________ 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