wierd why that happened, ive run my setup for ages in visceral and havent had problems (design issues of drum smashing motor shouldnt tarnish the brushlesses reputation )

shall see
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www.demon50s.com - Minimoto parts
http://www.youtube.com/user/HyzerGlen - Videoooozzz

Well I haven't given up on them yet, I will just be fairly cautious with how I use the next one. I guess they would have to be a bit more sensitive than just a dc motor.
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They say that he crossed the fine line, from insanity to genius.

I'm trying to decide if casting urethane around the outrunner will give me enough of a reduction for reiction drive, or if I run a timing pulley off to a tiny wheel. So either about 5:1 reduction to a final speed of 2000rpm, from about a 1kW motor, spinning a 7kg rim, 15:1 reduction for a final speed of 660rpm.
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They say that he crossed the fine line, from insanity to genius.

The reason that you couldn't spin up the shell is due to the low starting torque of the brushless motor - Glen's works because the drum has a much lower KE value than your shell. If you could get the shell started, the motor would power it fairly well. More reduction and a higher KV / larger motor would be my suggestion. You might also try Gary's slipping belt technique - it will be hard on the belt but gives you a friction clutch.

Casting urethane around the endbell of the motor sounds iffy: it would be hard to make a water-tight mold around the motor, you would have to really roughen-up the shell to get the urethane to stick and worse of all the combined heat from the motor and the friction against the shell will be very hard on the urethane, which usually has a fairly low operating temperature. Having said all that, I would like to see how it goes.
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Yeh, had I taken along my programming card, I would have given the slow starting options a go. We did try giving the shell a spin and then trying to bring the brushless up to speed but it didn't seem to help a lot.

I was running a v-belt to allow for slip, which may have been part of the problem. It was allowing too much slip since I needed an in between belt. I'm keen to try and sort out these problems.

@andrew: Can I still buy your spare brushless to drop in?
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They say that he crossed the fine line, from insanity to genius.

Hmm, I am surprised to see that the motor didn't spin the shell after you gave it a kick start. It might be that you had a bad motor vs battery voltage combination; I noticed that some brushless manufacturers have an optimum voltage listed. motors will run on much less but develop WAY less power. It seems that generally lower Kv motors (higher winds) like higher voltages - theres an experiment in there somewhere.
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

honestly those motors dont look very powerful at all either.. when you take them apart the magnets are tiny (barely 15mm tall) so the flux density must be very poor and the torque > next to nothing.

but i think you just need to stick it back together and have a look inside to see whats going on. that belt was so loose (no jokes trav ) you couldnt possibly load the motor up to any real degree.
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www.demon50s.com - Minimoto parts
http://www.youtube.com/user/HyzerGlen - Videoooozzz

the problem with brushless motors isn't the motor itself its the controller, sensorless controllers "guess" the position of the motor until its spinning fast enough for it to generate a decent voltage on the inactive coil and from there it can start driving the motor properly. If you can get a sensored controller it would be much better for RW use.
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Mechanical engineers build weapons, civil engineers build targets

The smallest sensored brushless motor for sale on a bot site is the Etek! Its a nice piece of kit, but just a tad over spec for a feather! Brushless motors with sensors seem rare outside expensive industrial situations; a real pity.
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

Given the construction of most brushless motors you could probably stick a hall effect sensor on the outside of the can and that would be good enough, with the leakage through the steel. Anybody who has one could you see if you can "feel" magnetic field through the case? see if a nail sticks to it or something. The hall sensor just needs to see the magnets in some form or fashion. Worst case you could hack some optical thing up with a stick on label on the outside of the motor.
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Mechanical engineers build weapons, civil engineers build targets

You would need two sensors to measure the direction of the motor as well as the speed. The little brushless I have here tends to go in reverse if the speed is ramped up to fast under heavy load.
I think the biggest problems with these brushless motors is that they were designed for model aircraft use. A aircraft prop weighs practically nothing so they were never designed to provide a huge amount of torque at start up. Also an aircraft is never intended to go prop first into the ground so the motors never needed to be very strong either.
Model aircraft brushless work fine for insect class robots spinning >1kg discs but they are a waste of money for heavier robots.
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You only need to know position. Its the same as brushes, they only act based on the position of the rotor they don't change with speed or anything. If you really want loads of low down torque (like at stall) then you need 2 hall sensors to give you absolute position or 3 optical sensors.

The motors are fine, its the controllers that are the problem, they just can't drive anything with inertia because they cant get into closed loop mode.
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Mechanical engineers build weapons, civil engineers build targets

Does anyone know if the soft start option improves the starting torque then? I would assume so, but I can't test it atm
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They say that he crossed the fine line, from insanity to genius.

It probably reduces the starting torque to make the load accelerate slower.
IE not what you want
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Mechanical engineers build weapons, civil engineers build targets

Yeah, that's how my brushless manual describes it - less start-up current to save the controller. even less use for high inertia loads
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion