Recent content by natem

Well making batteries more affordable would be the ideal spot to put it. Electric motors are old technology. They've existed for as long as we have had electricity, in fact the dynos used to generate electricity could also be used to create motors. So there is about as much to know about them...

Looks can be deceiving. It could be that the guy figured out some manufacturing process that would allow him to make such seemingly complex frame design done on the cheap or some other thing like that. I mean if the frame was just one big stamped item that could be turned out for 40 bucks a...

I always figured that if the motor was off on a moped then it's not motorized anymore. Depending on the jurisdiction it's probably not actually necessary to register the moped at all. In my state, for example, I don't have to register or insure it or anything like that. I can legally drive it...

I would not get to hung up about efficiency at the rear wheel like that. Efficiency is very nice at the motor because any wasted energy ends up as heat, which is bad, and puts heavier loads on the batteries. On a upright bicycle once you get over a certain speed inefficiencies in aerodynamics...

Well that's what a moped is. It's just a bicycle with a motor. It differs from state to state, but in mine (which I think is typical) is that: 1. It MUST have working pedals. A moped is a moped because it has pedals. If it doesn't it's a scooter. This is a legal definition for moped and if...

Wikipedia to the rescue: http://en.wikipedia.org/wiki/Sprag Or maybe not. The sprag patent from 1950's... http://www.google.com/patents?id=PKRIAAAAEBAJ&dq=2777551 Basically you have a bunch of little bars in the clutch that if you rotate it one direction they slide freely, but if you rotate...

As long as your controller can handle the surge then it should be fine. Devices at my work will use reverse polarity as a braking mechanism for brushed motors. I'd probably check out controllers designed for robot combat as they are designed to take high loads, be abused, and whatnot and would...

Depends on the state, of course. I don't know about Oregon. I know that in the midwest it's going to be much easier because we are able to avoid the whole environmental nazi brigade so far, but it's not looking that good. And on the west coast I expect that they have such little trust in their...

This is a very cool idea and I think it's actually very do-able... If you take the simpliest design, how much do you suppose would it cost to build? Hundred dollars in machine shop, 30-40 bucks for the backstop/sprag bearings, 50 dollars for the big spur gears, 20 dollars average cost for the...

Ya. I made my version just trying to figure out your concept. So it's definitely a variation on your idea. :)

Here is my rendition... background: (I know that everybody knows this and I know that you are not stupid, but I am just saying it for the sake of clarification and the description. Just so that everybody knows were I am coming from.) You know how when you spin you pedals in the wrong direction...

Do they make spur gears (or whatever) with one-way clutches like they do with freewheels? I think the technical term is 'sprauge clutch'. Because if so then the design should be relatively simple... You have have two sets of gears, one with a even number of gears so the output shaft rotates in...

Ya. I think your essentially aiming for: low gear going backwards and then high gear going forwards. (or visa versa). Is that right? Bicycles in the 1920's or so were able to do this using a single chain and two freewheels on the rear wheel. Some people have modern versions for the novelty...

Well if your going to go with the dewalt hammerdrill route then the already come with a very nice all-metal gear reduction in them. On the low gear the output shaft runs 0-400 RPM which is about perfect for a bike. If you take the drill apart you can shove in spacers to force it always to be in...

At that point it doesn't really matter. A bicycle, or motorcycle, is about the most un-aerodynamic vehicles you could possibly imagine using. The energy losses of a chain tensioner amounts to you spitting in a monsoon of inefficiency. :) It's a very cool bike, btw.