Aerodynamic & rolling resistance, power & MPG calculator

For Spreadsheets, Gear Ratios, Speed Calculation etc..

Moderators: Dan J, Diesel Dave, Crazymanneil, Stuart

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Sibbo
I luv the smell of Diesel...
Posts: 94
Joined: Sun May 22, 2011 12:01 pm
Location: Northern NSW

Aerodynamic & rolling resistance, power & MPG calculator

Post by Sibbo » Sun Jul 31, 2011 10:31 am

http://ecomodder.com/forum/tool-aero-ro ... stance.php

This calculator is good .

If you feed in 1.0 as the coefficient of drag for a normal unfaired bike......................... cd ,
rolling resistance for normal tires on a paved road 0.015 crr ...................... Is that right ? or higher?
I used .75 squ m as frontal area
Engine efficiency 40% ...........correct for a China diesel ?
Tick diesel as fuel .

It gives a pretty accurate estimate of speed and fuel efficiency .

I calculated the coefficient of drag of the Dreamliner fairing I posted once before and it's cd came up as .72 .
No wonder it improved fuel efficiency so much .
It calculated fuel consumption on the Dreamliner as 1.4 l/100km, Imp mpg 200 or US mpg 168 at 76km phr or 47 mph .

Sibbo
I luv the smell of Diesel...
Posts: 94
Joined: Sun May 22, 2011 12:01 pm
Location: Northern NSW

Re: Aerodynamic & rolling resistance, power & MPG calculator

Post by Sibbo » Mon Aug 08, 2011 11:45 pm

I've modified the engine efficiency to 30% on advice from the forum ...thanks !

The most interesting modification is changing the coefficient of drag figure .The boys on this site http://ecomodder.com/forum/motorcycles-scooters.html come up with some remarkable stuff .If you plug .7 into cd and rework the calculation the results are very good .

220 kg weight
cD .6
frontal area 7 squ ft
biodiesel


results in 1.25 l/100km or 226 mpg Imp at 45 mpg using 3.18 hp .
the same with a cD of 1
gives 1.94 l/100km or 145 mpg Imp at 45 mpg . Quite a difference ! 8)

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