Best reduction I would achieve

Whats the best reduction I could achieve With the motors below on 50mm wheels on a single stage reduction?

http://www.ebay.co.uk/itm/300511267976

Had a look on technobots but ive never used gears before so am a little unsure

http://www.technobotsonline.com/robot-s ... lator.html

Put in figures, get answers.

I've considered this to quite some length and with MOD1 gears you start to run out of weight and space around the 6:1 mark, 4:1 is more possible. Similar story with chains and sprockets.

50mm wheels are tiny though and means you need less reduction, but most gears will be bigger than that!

What you'll find is that with a single stage ratio you don't have alot of choice. You just need the biggest gear that can fit on your wheel and the smallest that can fit on your motor shaft. Normally that's around 5:1

If you go with bigger wheels and bigger gears on the wheel you will still get the same speed.

I ran those motors with a 7.5 to 1 ratio (12t pinion and a 90t Spur, mod 1). The bot ran on 120mm diameter wheels. I believe Will from team shock ran them in one of his featherweights on a smaller gear ratio so might be best to check the build diaries.

Those motors at 18v with about the biggest reduction I could got on 50mm wheels 40:12 (3.3333:1) would get a theoretical 18mph out of it.... bit slow :lol:

Though slight problem, 50mm wheels and invertable with motors 52mm diameter, not going to happen

52mm diameter. Sounds like Speed 900 or clone.

Means also 3 diameters of axle. 5, 6 or 6.35mm.

With the 6.35mm you could use , in theory a gear with a root circleof 8.5mm. With mod 1 that is Z10 (Mod*Z-(2M*1.25)). A rare and expensive size.
Also, it means a gear with undercut. Meaning the teeth are weaker than what the norm allows.

If we drop to a Technobots available size in steel, mod 0.7 Z12, root circle 8.4mm, that could be survivable. On a 60mm wheel, you could add a mod 0.7 Z80 gear(outer diameter 57.4mm). Giving you a gearratio of 6.667/1

But technobots goes only to Z72. And that's 6/1

So, if I use the data from my measurments, a 6.35mm axled Speed 900 clone runs 12Krpm@12V
6-1 gearratio to a 60mm wheel = 22km/h

I must admit. I don't know how mod 0.7 stands up in the Featherweight class. Never used anything else than mod 1.

I hope Will doesn't mind me saying this but he made up his own drive units for his latest robot with those 900Clones and given the Voltage, Motor RPM, Reduction and Wheel size that robot has a top speed of around 30mph, but in the drive test video moves around nicely!

Most people would consider 10mph a good/high top speed to aim for. Food for thought.

Getting there and maintaining is what matters. Tormenta 2 does just 10mph, but it reaches it in about 3 feet of floor space, and it has the torque to maintain it once it has hit another machine. That's why it appears quite fast. In a straight line it is easily outclassed by robots like Satanix, though.

I'd suggest aiming for a 2 stage gear reduction. It's harder but also easier, in a way. Bit heavier but allows for a stronger setup. With it you could gear those motors to say 12mph, a good deal faster than 90% of your opponents, and if others have geared to 30mph and the machine moves around well, imagine what it would be like with the freedom of torque and acceleration at 12mph.

Thats all good but with 52mm diamerter motora in an invertable robot with 50mm wheels, they wont fit inside the body

I don't understand how you managed to get this far without thinking about that, mate. :lol:

Why so set on 50mm wheels?

Quote:

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Originally Posted by mattsdragons

Thats all good but with 52mm diamerter motora in an invertable robot with 50mm wheels, they wont fit inside the body

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Go for a speed 700 then. Those don't run much faster than a Speed 900 clone.

And why 50mm wheels?

Also, you could go for Big Nipper or Hard setup.

Only just noticed their too big xD

Its from the 6wd crusher I bought, turning them into 2 robots, one with big armour and the other with a big weapon

Why not just build it that way it was supposed to be built or start from scratch?

Want to use the 6wd set us as its far too awesome not too use but is designed for 50mm wheels and would rather get 2 better robots and use the 6wd set up for invertablility

what machine is this?

It was calums new pinsor, he then sold it too me and im taking the weapon pod out for another robot with a bit vertical crusher and this one as a heavily armoured 6wd invertable rammer, 8mm T6 ali sides and 8mm hardox front and back and 4mm hardox lid

Its been built by some of the top guys on the forum, possibly some of the most meticulous craftsmanship too to make it specially designed to work a certain way on the available width. To take the weapon off presumably you need to remove the bulkheads that hold the weapon as they will be too high? Which means you remove the bit that holds part of the motors on, so you're left with wheels and a baseplate?

I can't understand why you wouldn't just go from scratch, buy 6 Gimsons and a chunk of plastic/metal and whack any sized wheels you like on them then you have a 6WD rambot sorted no problem.

Mostly because 6 gimsons is a couple of hundred ££££ which I aint got, I have a 6wd chassis here and I like the compact design of it so easy enough to get all the working I need in a small enough to make with stupidly thick armour and it will still be under weight

Are you 100% sure the wheels on that are 50mm?

I'd need to look up pictures to check, but if it's the chassis I'm thinking of, the wheels used on it were 75mm ones. They were blue wheels and 50mm is tiny for them. The overall diameter of a drill motor is roughly 45-50mm and that chassis had drill motors fitted when Calum had it, with plenty of clearance on either side.

Are there any pictures of the machine? I don't understand why you wouldn't want to run it as is

I was going to ask why you would ask about 50mm wheels on 52mm diameter motors then immediately, in the next comment, suggest that it would be impossible to do so too but thought it'd be pointless. Fairly certain they'll be 75mm ones thought as Jamie has suggested.

2 robots will be more expensive than one I might add and if Gimsons are too expensive then ESCs, batteries, motors etc etc for two robots instead of one will be too. If you're insistent on butchering that robot though, rather than using things that won't work, would suggesting you use drill motors (as the chassis was designed for) be a ridiculous suggestion? I imagine it will in a way which I have not foreseen...

Gary,

viewtopic.php?f=166&t=5235

Most likely 75mm wheels then, ive not actually measured and ive had it stored away for ages but then in that case they should work okay

Well ive made myself look like a tit as usual :lol:

I would happily run it on the two drill motors, but the fact that my aim is a heavy armour with powerful drive robot, thought it would be best to use some bigger motors

I would rather make them into 2 machines as both together would have created a single feather that is none invertable and with an over complex drive system. would rather put the weight into bigger batteries etc for a big weapon and will be done over time

Judging by the pictures, those are 75mm wheels.

:|

Probably high time I actually got it out and did some calculations etc with it to figure all this out as I was just thinking about it the other day and for some reason remember 50mm for the wheels