Thread: Electric motorbike racing
About time I updated this...
We won the races in Anglesey and Pembrey, messed up in Cadwell and won all three races in Portimao which meant we won the overall championship. We got a top speed of 145mph in Portimao, though still limited to 50% power output due to issues with the motor controller, so the focus is to make our own now.
In terms of machining, I made several more sprockets - this time from tooling plate and they held up well. Also modified the water cooling block on the motor, as the rider ground it down a bit when leaning the bike over.
Some pictures here:
... and the obligatory action shots:
Can't wait for the TT next year now - so many things we can work on and improve. The current plan is to make some small changes to this bike and make a whole new bike, so we can take two to the TT. I'm keen to design a frame that could be machined from only CNC milled parts, so no welding and bending aluminium tube. I think it would give some useful design possibilities, in addition to making it easier to replace parts when the inevitable crash happens.
P.S. If anyone has ~£5000 sloshing around, let me know and you can sponsor us
Last edited by Jonathan; 08-11-2015 at 08:49 PM.
I must say this is pretty cool, I wish I'd seen this earlier, I live in Derby and Donnington isn't that far, congratulations and I look forward to your success next year.
Really enjoyed reading this thread Jonathan! Keep us posted on any updates and thanks for all the effort with the pics.
The bike project is getting going again. One of the nice things is getting to machine some more interesting materials, e.g. a £300 piece of titanium bar for the motor shaft:
I chose titanium purely for the 'easy' weight saving. We're getting the motor core length a little longer for more power, so the increase of weight from this will be offset a bit by lightening the shaft. My lathe seems to be coping OK so far. I first made sure the tailstock was properly aligned as the tolerances are pretty strict on this one and spent the rest of the weekend doing the roughing cuts.
More fun than millions of battery terminals:
I programmed those using Octave (though just about any language would have done), parametrically so I just have to enter the dimensions and the rest is worked out. It seemed worth it to get an efficient toolpath - probably wasn't, but more interesting!
Next thing will be some parts from aluminium and carbon sheet to make a new tail unit packed with batteries.
Quick update, I made some progress with the titanium shaft this weekend. I almost finished the lathe work:
I used a CBN tip for the finishing as it was able to take extremely light cuts, so no "hand finishing techniques" required. The tolerance on the part measured above was 50.003-50.015, so I made it to 50.010 as the young's modulus of this material is lower than the steel that fit was specified for, so making the interference slightly greater seemed the safe option (though it probably wont matter in reality).
Next weekend I'll do the last bit of turning on the other end, then it needs a few slots miling and some holes drilling to mount the sprocket.
In other news, we should be getting the new bike frame delivered within a week, so watch this space. Race dates have also been confirmed, so I'll be in Belgium, Germany, the Netherlands, Portugal and the UK!
Last edited by Jonathan; 14-03-2016 at 10:36 PM.
I double checked all the diameters now it is off the lathe and it's well within tolerance - e.g. the longest diameter is 0.011mm different from end to end, but the drawing specified up 0.04mm here.
Next step is to mill 3 keyways in it and drill some holes for the sproket.
We also got some new brakes delivered from PFM. Apparently they're really good ... I don't know about brakes.
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looking good jon
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