Low drag is important at ALL speeds.
Back in the 50's Royal Enfield fitted a 350 Bullet with the 'Dreamliner'
fairing.
Despite adding 45lb of weight, it improved the 15-40mph accleration time
from 6.4 to 5.5 seconds.
Why?
Because it lowered the drag so much, there was more power available for
acceleration.
The tests were conducted at MIRA (motor industry research association).
Details can be found in Tony Foale's book.
Paul Compton
www.evguru.co.uk
www.sciroccoev.co.uk
www.batteryvehiclesociety.org.uk
www.morini-mania.co.uk
www.compton.vispa.com/the_named
----- Original Message -----
From: "dale henderson" <[EMAIL PROTECTED]>
To: "ElectricMotorcycles" <[email protected]>
Sent: Wednesday, March 12, 2008 9:21 PM
Subject: [SPAM] Re: [ElectricMotorcycles] Craig Vetter DVD
yes 2-3x is substantial, but not at the cost of safety and not compared to
the 5-10x the gas bike were getting, but you are right Cd is not
everything so just changing Cd in an equation might not produce real
useful predictions
and as someone pointed out low drag is only important at high speeds and
under ideal conditions. until we can make ebikes go over 100 miles on a
charge [yes we can now, but most of use can't afford the batteries] then
focusing on improvements in long duration, high speed travel is not a
major concern to me right now.
i would like to learn more about how to reduce drag though, for example
i've been toying with the idea of studying effects of tassels on the rear
of a bike. i would like to know if having a series of tassels on the rear
would break up the air and thus reduce drag? since i'm more of a chopper
fellow wearing a leather jacket with tassels and a seat and saddle bags
with tassels would be a simple addition.
and is there any data on the effects of wind shields on bikes? angles,
sizes? maybe vetter knows?
john fisher <[EMAIL PROTECTED]> wrote:
don't know bidwell's calcs.
2-3 X qualifies as "substantial" to me, while 30% does not.
Vetter used to be interested in LSR racing. Those designs aren't usable
for street or track.
CD is not the only factor in aero calcs - its wildly misused all over the
internet. In fact most say the tail is more
important than the nose. The thing *I* think its important to remember is
you can't calculate the actual drag without
either 1) a cad model and major-league software on huge hardware, or 2) a
wind tunnel that lets you test the bike at
lean. You can mount the bike on a trailer and get some idea, but my point
is, its really hard to measure aero effects.
That said, everybody guesstimates based on previous designs.
theres some other good, trustworthy links out there, I'll look tonight.
Wikipedia may be pretty good on this by now.
dale henderson wrote:
i got my results from the equation found in biddwells [spelling] "EL
CHOPPER". i've found the equation works very well for my current bikes,
so i just tried reducing the Cd, i even tried 0.1,
harry
Albuquerque, NM
http://geocities.com/hendersonmotorcycles/blog.html
http://www.austinev.org/evalbum/1179
http://geocities.com/solarcookingman
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