nicks90 Posted September 22, 2010 Share Posted September 22, 2010 interesting idea! sounds pretty cool. I was recently looking at various electric motors to power my pushbike when its got the little sprogs bike trailer hooked on the back (i'm way to old an fat to cycle up hills with a 25kg trailer + 20kg 3 year old behind my bike!) From my research i found that the torque and stall speed wasnt really that much of an issue if you geared it right. As long as the motor produces enough power to get the right speed you want via the right gearing, torque is flat from zero to max speed and it isnt really an issue. I was seriously impressed with the conversions you can do to car alternators to turn them into dc motors. They are light, powerful and will run for an awfuly long time under loads and little 45amp car alts from small euroboxes are very small yet still pump out 600w at 12v. From my calcs a 600w motor would provide me + bike + trailer + child + 12v leisure battery (total weight 150kg)a top speed of 25mph roughly. maybe the friction from tracked skis would mean you need more power, but that depends on the speeds you want to achieve. I would be very suspect that a winch motor (although easily powerful enough!) would survive prolonged use without overheating. How would you power these things - batteries are heavy unless you go for one of them very $$$ LiFePO4 batteries. Quote Link to comment Share on other sites More sharing options...
Night Train Posted September 22, 2010 Share Posted September 22, 2010 Have you looked at belts that have a cheveron tooth pattern(click on the 'Y' type belts)? They would grip sideways and leave tiny tractor tyre prints. Using Harley Davidson toothed drive belts inside out as caterpillar tracks. On that note I'll go OT. Can you get hold of them cheaply? How about toothed pulleys? Do you know what standard pulley type and sizes there are? Is it a standard HTD type belt or is it some other standard? Just got a Honda VFR750F swing arm for my trike and was thinking about using belt rather then chain. I know that a Harley belt will probably be strong enough but don't know what width or pitch of 'off the shelf' belt would do. Cheers. Quote Link to comment Share on other sites More sharing options...
simonr Posted September 23, 2010 Author Share Posted September 23, 2010 Can you get hold of them cheaply? How about toothed pulleys? Do you know what standard pulley type and sizes there are? Not really. There is a classic bike shop shop in Horsham who is looking out for worn but not broken belts for me. New ones were too much money! Because I'm running them inside out - I don't need toothed pulleys. My plan for batteries is LiFePo packs made for RC Car racing - like that chap in Brighton had when we went to visit. Controllers will be single quadrant (as I neither want reverse nor regenerative braking) DIY efforts using the same IGBT's I've used in my charger. Batteries and controllers in a back-pack to minimise the weight of the skis. Si Quote Link to comment Share on other sites More sharing options...
roguevogue Posted September 23, 2010 Share Posted September 23, 2010 I'm looking forward to this one. Quote Link to comment Share on other sites More sharing options...
simonr Posted September 24, 2010 Author Share Posted September 24, 2010 I'm looking forward to this one. Actually, I was planning to use you or Guy as a test-pilot. JST only escapes by having already mangled his leg - it wouldn't be a very scientific test of leg mangling! Si Quote Link to comment Share on other sites More sharing options...
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