The Linear (recumbent) Booster

this is an incredible thread! Thanks for all of the posts and information. I am looking into doing the exact same thing when i buy my linear in the next few months.

I have a few questions

1. Y are you all choosing that kind of motor drive as opposed to a direct drive hub motor? Cost, efficiency, things that I have yet to learn..etc?
these come to mind http://www.electric-bike-kit.com/hill-topper.aspx?gclid=CJmElorTuqcCFaRa7AodYBwNYQ & http://www.ebikes.ca/

2. I am looking at the linear limo3 or the linear roaster swb. Would a SWB lend it self as well to electric boost as a LWB?
 
I chose a through the gears drive for two main reasons. I wanted the drive system to be light enough that I could still pedal the bike easily, and I wanted enough torque to winch me up steep hills. (there was also a fair component of seeing if the crazy plan would actually work)

I don't think SWB or LWB is particularly better for electrification. I find a LWB bicycle easier to handle in tight places and stop-n-go traffic. On the other hand my Performer High Racer is a pedal powered rocket (it has a very reclined back seat) and would have impressive speed/efficiency if electrified. (i.e. ~300 watts would propel the Performer at ~30mph on level ground) The linear is especially nice for electrification experiments because of the extruded main tube, the screw on clips make for a clean install.

I am currently tempted to make a traction drive system for my Performer. I'd pattern it after one of the several small friction drive assists described on the endless-sphere. Having a light 1000-1500 watts "turbo" button would just be heaps of fun. (and true to the "turbo" concept, I'd size the battery for at most 5-10 minutes of power) The "turbo" button would also let me make better use of the human engine. I.e. I'd let the "turbo" handle any power spikes, while I contributed the bulk of the energy for a ride at a slow and steady pace.

Regarding RC motors and overheating. I'm not too worried as I was never pushing the motor very hard. Also I rarely used the motor for more than a minute at a time, so it had plenty of time to cool.

Lawson
 
lawson,
are you saying that a direct drive hub motor powered bike will be harder to pedal than if said motor was not on bike ? If so can you please give me an idea how much harder it will be? Also, i am thinking a better design will not be as hard to pedal as a cheaper/ poor design....your thoughts? thx

oh yea...what the latest on your project.... did it work out like you wanted? Have you had a chance to ride the linear limo and compare it to the iowa built ones of yesteryear?
 
The cheap brushed hub motor I tired was about the same as always riding on a nearly flat tire. I'd expect a brushless hub to be more line an underinflated tire, and a geared hub with freewheel to be nearly imperceptible.

Unfortunately the weight is more of a problem with hub motors. High torque slow speed motors are always heavy. The geared hub motors do improve on the weight, but are usually geared for 15-20mph top speed so still need 2000 or more watts to climb steep hills (i.e. >12% slope). In the end, I'm only willing to tolerate pedaling around about 10lbs of electric system, and I haven't found a hub motor that will climb steep hills at that weight.

The latest on this project is that I've stopped working on it. My initial experiments erred too much towards low weight and broke. Meanwhile, I'm in better shape and don't feel I need assist anymore.

Haven't had a chance to ride the new Liner 3.0. It looks like they've managed to improve on an excellent bike though.

Lawson
 
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