Torque required for hammer to self right?

[daveimi]

Hi, quick question. To build an electric axe capable of self righting what sort of size of motor would I need to look at to power it?

[Ellis]

Depends on the gearing! A scooter motor will have the beans at a high ratio, but a standard drill size 550 motor will too at a low enough ratio.

Can you give any idea what sort of motor you had in mind?

[maddox10]

Speed 900, 6S, 30-1 gearratio, 300mm long arm. Does the job very aggressively.

[daveimi]

Erm, my fav robots are Little Hitter, Tiny Toon (not relevent lol), b-e-t-a, basher

I have a nearly finished robot at circa 6kg. Was umming and arring about building another for a cluster or armour this more and going with a big hammer, although then it won't be invertable.

So was looking into it and most are pneumatic, but would rather go electric and wanted to see if I'd be able to sort out a big enough motor with a 6kg allowance. To be honest I don't know what ratio to be looking at, I think it'd depend on the motor. I'd hoped it would be manageable with something like a pair of wiper motors etc. But if it needed something like a wheelchair motor in I'd never do it in the weight I don't think.

[daveimi]

Sorry, forgot to say,

So I was just looking for an indication of the power it needs in the first place to self right if i move towards a better more rounded shape etc.

[maddox10]

If you want to build a 6 kg machine, you should have a look at the German Raptor rules.

But to make the search shorter.
No brushless ,no brushed larger than speed 700 size and no rare earth magnet motors allowed.
12V SLA, 10S NiMH, 3S LiPo or 4S LiFePo4 batteries.
Voltage boosters or extra batteries allowed for valve control.

The rest is classic featherweight rules.

[daveimi]

I didn't deliberately end up with a 6kg robot, its just the way it's ended up, hence either building a second as a cluster or trying to build a hammer to go on top. Sorting the hammer won't be that bad, I'm just not sure of the size of motor and torque that I'll need to be able to self right.

[Daniel]

Avenger has a 300W scooter motor on 22.2V, a 80:11 reduction and a 300mm axe and it manages to get a bit of air while self righting. A quick guesstimation while looking at the motor power graph (chinese, so don't trust it) and guessing the rpm, I'd say it gets 30Nm at the axe. Can't decided if that's too high or low, so I guess its close.

[daveimi]

Do you mean a scooter as in an electric wheel chair type of thing? Do you have any pictures of Avenger?

[maddox10]

The motor Daniel mentions is a large, heavy motor, on the edge of usability of feathers. Also called EV warrior.

Most we see now are Chinese clones.

I do happen to have one in my spare box.