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Old 12-08-2008, 12:51 PM   #1 (permalink)
MetroMPG
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Join Date: Nov 2007
Location: 1000 Islands, Ontario, Canada
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Blackfly - '98 Metro
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Arrow Online tool: shows aerodynamic drag, rolling resistance, power required & est. MPG

Aerodynamic & rolling resistance calculator - EcoModder.com

Back in the day, krousdb made a spreadsheet to calculate aero & rolling resistance forces against his del Sol, their respective power requirements, and effect on fuel consumption at various speeds.

I've ported/expanded the spreadsheet into an online tool which asks you to enter or accept default values for...
- vehicle weight
- Crr (coefficient of rolling resistance - .008 represents a low rolling resistance tire on a smooth surface - see Wikipedia for other sample values)
- Cd
- Frontal Area
- Fuel energy density (in Watt hours / US gallon)
- Engine efficiency
- Air density (rho)
... and it spits out a table showing resistance force values, estimated power requirements and fuel consumption across a range of speeds.

It's online at EM here: Aerodynamic & rolling resistance calculator - EcoModder.com

It's not perfect (e.g. engine efficiency changes with load in real life, but remains fixed at the value you supply for all speeds in the calculations for fuel consumption).

Discussion, questions, suggestions welcome.


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