Thread: 40 MPH Club
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Old 01-24-2015, 11:19 AM
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Davezilla Davezilla is offline
Motorized Bicycle Elite Member
Join Date: Mar 2014
Location: San Antonio Texas
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Default Re: 40 MPH Club

If you could get one of these engines into one of those streamliners then maybe gear it so it could get moving and just let it accelerate slowly up to top speed, if there's enough road and it's geared so it could do 80 at peak power it should be able to do it, wind resistance does get stronger as speed increases but it quadruples instead of doubling when mph doubles.

the bike would also have to be pedaled or pushed up to 30mph or so if geared this high before it could accelerate on it's own.

The other factor in this is that human power has been measured around the 1/2hp mark, but at the rpm we can pedal, the torque is way higher so gearing for human power the big sprocket is on the cranks and the small sporcket is on the wheel and it's backward from engine power where we can have much more horsepower but a lot less torque. I'm guesing a china Doll makes about 2 1/2 to 3 lb/ft torque at best so we need that rpm and gearing to get speed, we also need it to be either geared in a way that it can accelerate on it's own but lack a little top speed or have a 2 or 3 speed transmission because if it's geared too high and the engine's max power rpm is too high, it may not be able to overcome the wind resistance to make it to the powerband which would also make it a lot alower than it could be... This is easily noticed in some cars and motorcycles that can actually go faster in 4th than 5th, or faster in 5th than 6th, and it's really noticeable in a truck that has poor aerodynamics.

I do beleive that we could get a very streamlined bicycle or trike up to 80 or 90 mph, or maybe even faster, but it'll need multiple gears or some type of push assistance to get it into it's powerband, then from there it's all about tweaking the top gear ratio to get the max speed.

Anyone else in here remember these little car/motorcycles from the early 80's? I think if we built something similar but smaller, lighter, and with improved aerodynamics, maybe over a tadpole recumabnt frame it could hit some impressive speeds...
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