I could do belt drive but then I'm left with the issue of regen when not running the motor. Same goes for friction. Either could be alleviated with a mechanical clutch, but I'm not sure I feel up to engineering something like that just yet. I'm not too worried about noise for the first prototype, it won't be seeing a lot of action and exists primarily to let me take measurements on what will need improvement for the second prototype.
I've already decided the first prototype won't be a velomobile or have a back seat as shown in my concept drawings. For simplicity's sake it'll be just a trike with a motor and a single 12v 20ah car battery.
Speaking of simplicity and motor, I'm thinking the simplest setup will be to place the motor on a "rack mount" style platform above the rear wheel, with a chain running down and forward to a free hub behind the seat, and another chain running from the left side of that hub to the left side of the drive wheel. This will minimize the amount of structural work I need to do below the seat, and will allow me to stay closer to the original thunderbolt plans for this first build.
The second prototype will use a more boat-like "keel" for its spine along the bottom, with frames mounted perpendicular and a keelson fixing them in place. Deck beams will be fitted to the frames as in a wooden boat, and will serve a double purpose of creating a platform for the seat and a compartment below the center of gravity for the batteries / motor. This will place the seat about 6 inches higher off the ground than in the standard thunderbolt design, but will give more room for a potential passenger, cargo, and myself, as well as a mostly enclosed area for the motor / jackshaft free hub which should reduce some of the noise.
Since it'll be mostly enclosed I'll probably have to add some PC chassis fans and maybe a heatsink for some parts to keep them cool, we'll see. Lastly the boat-like frames will give good anchoring points for the upper half velomobile frame while forming the lower half themselves.
Anyhow, it sounds like my best bet would be 16 -> 60 * 16 -> 60 which would give me just a hair over 14:1, right? Could my motor even handle that much torque?
How do you have yours powered to get that much out of 12v? Doesn't that use up a lot more amps = a lot less run time? I'm not terribly interested in going faster than 20mph but I WOULD like to maximize my range. On my regular upright mountain bike I can sustain 17mph on the flats for quite a while, it won't make much sense to go electric if I can't do that same speed for at least a couple hours. Also what is the inverter for? I thought those were for converting AC to DC and vis-versa, is your motor AC? My motor is 120v DC, 18amp, permanent magnet, not sure if it's brushed or brushless. It's essentially identical to the treadmill motor Amberwolf's got.
No I haven't got a functional digital camera right now. I lost my nice one in the last move, and lost the memory card for the crummy one a few weeks ago. I'll clean my room and go through boxes tomorrow, either the missing card or missing camera should turn up, and if they don't, I know the kids' fisher price digital camera (not even 1Mpx but hey it works!) is in one of the boxes of toys.
Tomorrow I'll bolt the stays to the frame, cut out and glue the gussets, and hopefully cut out the dropouts and bolt them to the stays. We'll see. Hmmmm It's 2am, I should probably get some sleep since by tomorrow I mean today!
Edit: Oh, and speaking of PC chassis fans, over a decade of work in the IT industry has left me with a LOT of dead computers gathering dust. I'm wondering if metal from the chassis of these, though thin, could be used to reinforce layers of wood or at least to make little brackets to keep wooden parts from bending or moving too much... hmmm...
. Trust me: been there, done that...
