Can 1983 Honda VT-500 Meet the Vetter Challenge?

[redyaris]

On paper with the help of Tools:- Aerodynamic & rolling resistance, power & MPG Calculator, the answer is a definit maybe.

Variables for these results:

Vehical weight: 300kg/660lbs
Crr: 0.15
Cd: 0.25
Area: 0.7m / 8 ft
Fuel energy density (Wh/US gal.): 33557
engine efficiency: 0.22
Drive train efficiency: 0.95
Parasitic overhead (Watts) 0
rho: 1.22 kg/m3

MPG at 70mph = 101.19 MPG

If the Cd is 0.22
engine efficiancey is 0.25
parasitic drag 600 watts
then mpg at 70mph is 110.8 mpg

[Frank Lee]

I don't know if it's possible to get .25 Cd with an open cockpit, especially one that isn't recumbent. Is that 660 lbs with rider?

[drmiller100]

drive train efficiency for a chain drive should be a bit higher then 95.

I'm with Mr. Lee - .40 is probably more realistic, and aero is where you should REALLY focus.

[Frank Lee]

It won't be more than .95; as laboriously explained, there's a lot going on between engine and wheel besides that final drive chain.

[redyaris]

Originally Posted by Frank Lee

I don't know if it's possible to get .25 Cd with an open cockpit, especially one that isn't recumbent. Is that 660 lbs with rider?

I don't know either and may never know, the only thing the Vetter Challenge will tell me is if the bike can get over 100mpg, or not, under Vetter conditions.

Yes the 660lbs is with rider.

The numbers I am using show what has to be achieved in order to have any hope of meeting the Vetter Challenge.

[redyaris]

Originally Posted by drmiller100

drive train efficiency for a chain drive should be a bit higher then 95.

I'm with Mr. Lee - .40 is probably more realistic, and aero is where you should REALLY focus.

Who is not focused on aero?

[Frank Lee]

The saving grace might be that they don't go 70 the entire time? Or do they?

Is he looking for 100+ mpg, or is it 120 mpg now?

IMHO I knock 15% off the calculated fe values for "real world" driving of cold starts and starts and stops. Hypermiling can get that back and then some but I understand you can't do much of that with Craig behind you.

[low&slow]

Very interesting ! ( lighting cigar with $5 bill )
How heavy is the VT 500 only? This calculation definitely shows how critical the aero package is for achieving the optimal mpg. What are you making your dustpoin fairing out of? Any pictures yet?
Best wishes & Happy New Year, Vic

[redyaris]

Originally Posted by low&slow

Very interesting ! ( lighting cigar with $5 bill )
How heavy is the VT 500 only? This calculation definitely shows how critical the aero package is for achieving the optimal mpg. What are you making your dustpoin fairing out of? Any pictures yet?
Best wishes & Happy New Year, Vic

I'm guessing the VT500 is around 400lbs on its own.
The dustbin fairing will be made of aluminium and painted styrofoam inuslation.
thumbnail is attached to the original post, more will be slowly forthecoming as progress is made.
happy nu yr.

[low&slow]

Ahh, I see!! nice start !