bobc wrote:2 motors arrived today.
I note that the prop connection is at the turning end of the outrunner & I'm a little concerned about the practicalities of keeping 4 motors in synch on a single 8mm shaft if they're just attached by grubscrews. Basically I'm thinking that a keyed driving collar will have to be made to take the torque from outrunner to shaft via the 4 screws provided for the prop adapter.
Suggestions & links to suitable hardware gratefully recieved....
When I stripped one of my motors I found that the 8mm shafts had what looked like CNC machined flats at the places where grub screws fit. The shaft flats were configured so that the shaft could be re-positioned to take the drive from the bearing end, rather than the bell end.
If a new, longer, shaft was similarly machined with accurately located flats, then I think it would be OK. These motors have a tough time in the big aerobatic models they are often used in, so I feel reasonably confident that they will tolerate EV use OK.
One way around any potential sync problem is to use a distributed controller topology, effectively individual controllers per motor. This is what I'm doing for my test rig, with separate, very cheap, controllers for each motor.
They don't feel like 2500W when you pick 'em up do they ;^)
No, they certainly don't! Holding a motor rated at over 2kW in the palm of you hand brings home just how tiny these things are for their power. Apart from the advantages the light weight and size has in an EV, one of the big advantages is that they are relatively cheap to post, giving a significant additional saving over bigger motors.
Kelvin,
I'm not sure if I will get down to the show this weekend, I'm currently finishing off a home-brew CNC machine for carving moulds for composite parts. I want to make decent bodywork for the bike, as it looks a bit Heath Robinson at the moment. Hopefully, the CNC machine will make it much simpler to make complex 3D part moulds, up to about 500mm x 600mm x 300mm.
Jeremy