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Re: My new project

Posted: Sat May 18, 2013 10:19 pm
by Beemer
THAT is a testament to you. :wink:

What next? The bikes consumption therefore its range is mostly affected by air resistance. Suggest perusing Craig Vetters website?
http://craigvetter.com/index.html
There is a Dutch guy who has slipstreamed a Honda 100 to get double the mpg and it keeps most of the weather off him.
http://www.velomobiel.nl/allert/Recumbe ... orbike.htm

http://www.youtube.com/watch?v=a0NRW7_B2Ug

Re: My new project

Posted: Sun May 19, 2013 8:13 am
by charlesb
Yes, that should be by next task. As you can see, it's definitely a fair weather bike at the moment. The electrics under the tank should be fine, but the batteries need protection. I thought the cage should make a good frame to wrap a cowling around, with a matching aero screen, I'm just trying to figure out what to make them out of. I've had plenty of experience with glass fibre in boat work, but the weight soon adds up. I could beat an aluminium one over a wooden mockup, or even a vacuum mould. Any suggestions?
I can get a good 5 mph extra at 50mph just by tucking down low, so it's about as aerodynamic as a brick at the moment.

Re: My new project

Posted: Sun May 19, 2013 10:42 pm
by Peter Eggleston
My milk truck used to have the aerodynamics of a brick, so I chopped a foot off its height.
Now it has the aerodynamics of half a brick. Hope this helps. :lol:
Peter

Re: My new project

Posted: Mon May 20, 2013 7:33 am
by Beemer
This for me is mainly a thought experiment but I've done bits and bats.
I'd experiment with cheap stuff at first so you can find what issues that might turn up.
For a start, I'd never cover the front wheel front of the axle because of side wind issues. The body can fit closest along the forks and allow full wheel lock. Don't forget the wheel spray inside!

The material I'd play with would be 4mm Correx; its naturally stiff but it's not so good for compound curves. Stronger bends will need you to run our finger nail along the inner sheet along the corrugations it to bend. If you want compound curves it would have to be like a Zeppilin. A good glue gun works great on this stuff.

However, if you make a structure to support as few sheets as possible then I suppose you can simply use suitable large headed bolts or screws on any suitable shiny plastics.

To make a super fancy shape to fit the bike I suppose the best way is the polyurethane foam sheet and block route. You build the stuff to the bike and use a sanding block to carve the shape. Keep the hoover close by! Glass the outer surface. Smooth for painting. Take the whole thing off. Dig out the foam and apply more structural glass layers on the inside. Nuts, pegs, clips and reinforcing strips can be glassed in. Glassing completely around foam can make it very stiff indeed.

To help keep the bike clean through all this, I'd wrap it in cling film! :lol:

Re: My new project

Posted: Sat Jul 13, 2013 2:35 pm
by charlesb
Well I've been running on the road for about a month now. It tops out at about 50mph. That's about what I hoped for on 48v with a 13:60 ratio. I tried 15:60 and although the chain was quieter, I coudn't get any more speed, just increased current, and the motor started to overheat and cut back the controller. 13 teeth is definitely the smallest you can go on a 530 chain. If I was starting again, I would make the rear sprocket as big as physically possible.
I'm getting a safe 50miles with the 60ah batteries as long as I watch the current. There is probably still quite a bit of tweaking still to be done on the controller, but I'm pretty close.
the only real issue I have is that the motor still gets pretty hot after a 25 mile run - slightly to hot to touch, and then the controller is cutting back. I've called John at Motoenergy, and he has checked I've got the correct fan rotation.
I'm considering either some ram air ducting,or maybe an electric fan, though then I'm wasting more power. It's the slow revs at high current which is worst, once at speed she's O.K. Any ideas?
I've got just enough room to squeeze in four more cells, so maybe in the winter she will get a boost.