OK, I'm building a heavy... But need some help...

Yeah, cordless drill motors are nowhere near powerful enough. With Bosch's you'll need gears, a gearbox or chain drive, which can get complicated engineering-wise. £500 is do-able, but I wouldn't go expecting too much on that budget. A Wotty alone is close to £300. We built our first heavyweight, Monolith, out of wood and an old wheelchair we got off eBay, using relays to drive it That one still cost us a fair bit, and it lasted for precisely one fight before we had to dismantle it and start again.

You could use Bosh 400 if you can get any ask on the forum if any bodys got any spare. I am using them in my new heavy. test vid of them worklng at 12v dont use them at a higher voltage
http://www.youtube.com/watch?v=eqWjG_VuonI

As long as they don't give that mosfet whistle then they would be good, yes. Nippy. What ratio should I use them at?

George@TeamZog

http://i661.photobucket.com/albums/u...ers/Apollo.jpg

Basic CAD Drawing of what it will end up looking like...

George@TeamZog

Bosch GPA 400 data sheet: http://www.boschmotorsandcontrols.co...2003/index.htm

You can figure out the gear ratio using the circumference of your wheels, how fast you want to go and the rpm of the motor.

For your first heavyweight robot, just go for wheelchair motors + wheelchair gearboxes + wheelchair wheels. Seriously.

does anybody remember this robot ?

http://www.wjweb.nl/gravity5/g43.jpg

http://www.wjweb.nl/gravity5/g42.jpg

Perfect example of a cheap robot, although if you put more time in it it could even look decent ;)

It had wheelchairmotors/gearboxes/wheels, and 1 sidewinder speedcontroller (can be had for 200 gbp) as a drive system, and it frickin rocked. I had so much fun with it, incapacitating BOTH top of the line drive/rambots (storm2 and tornado) in 1 big heavyweight fight, and also putting dantomkia in the pit ;)

So go ahead, get cheap stuff (but DO get a decent speedo) and have a lot of fun !

the rule of thumb for working out a gearbox ratios...

Take your wheel size in inches and use that gear ratio !

For exambple, 10 inch wheels, use a 10 to 1 ratio.

JOhn

Thats a good tip from Jonno.

I agree about wheelchair motors though, for a first try they are perfect, you don't have to worry about getting them geared up and can even use the wheels that the often come with. You just attach them how you want and you're away.
An earlier team heavy I was involved in, Cabrakan, ran on wheelchair motors and just won last year's best newcomer heavyweight award, so don't count them out as rubbish.

Put a couple of wheelchair motors on 36V and you have a nice drive train. I did take the brakes of of them though.

I believe early on in this thread people were being cautious. I will still say build yourself a featherweight first. The amount of knowledge you can gain will help you on your way to build a heavyweight. Its all fine and dandy to say your parents are backing you but i think your parents dont really understand the task ahead. If i were your parents i would be looking and asking on the forum whats involved in a heavyweight robot.

I personally would start either with one of jonno's ratz or a simple featherweight.

Jonno aparently ticking everyone off........well i think the community were more concerned about your saftey not putting you off building a heavyweight.

Gary had the best idea.......if you really really sure you and your parents can handle a heavy the best thing to do is wait for one to come up for sale and then have a serious lesson on how it works and how to play.