Thank you mate ill have a picture of few design soon

just playing witha basic idea for my first bot in the front it will have a spear like weapon that will remain inside the chassis untill fired then it will go back inside so it doesnt get damadged i would probly use a piston for this

Hey i ono there is probly an answer already out there in one of the threads already but what are the advantages of 18 volt drill motors over a 12 drill motor does it have more torque and speed or does it just consume more power

18V drill motors are usually a little pore powerful than 12V ones. The main advantage of higher voltage motors is that most kinetic weapon motors work best at 22V or higher and the 18V drills don't overheat on 22V as much as lower voltage motors.

If you are going with a pneumatic weapon that doesn't need high voltage, then the only real advantage of 18V motors is a little extra pushing power.
_________________
Australian 2015 Featherweight champion
UK 2016 Gladiator champion

ok nick thank you i have just looked at some cheep drills from kmart the 12 volt in $22 the 18 volt is $35 given that i want to make a ramming bot do you think that the 18 volt would be the better option for some extra pushing power.
sorry if im being a pain but i do really apreate the help.

for armor i was thinking about using (high-density polyethylene plastic)cutting boards as i have seen some of the other guys use this because its cheap light weight and has a high tensil strength with the main frame of the robot welded from steal tubing
but once again i cant decide if this would work on not because i aim to build a ramming bot world steal or alloy armor work better but then i have to take weight restrictions into account haha i feel like im going around in a circle.
maby ill wled up the from and test the bot with various armor and see how it performes.
this bot building stuff really gets you pumped haha

I would go with the 18V drills, but only if you are totally OK with the extra $13 per drill. The gearboxes are likely to be exactly the same and the other parts in a cheap drill are not much use in a bot so you are just paying for the higher voltage motor.

I would definitely only buy one drill to start with. Disassemble it VERY carefully and check out the gearbox and motor to see what the quality and gearbox style is like - if it is particularly crap quality or the end of the gearbox is hard to mount, put it all back together and return it. If you haven't already looked at them, check out Angus's excellent drill tutorials: https://www.youtube.com/user/RobowarsNSW

HYDPE armour works well, just make sure it is very well attached to the underlying steel frame. HDPE absorbs impacts quite well, so I would make the front of a rammer from steel and the sides & back from HDPE.
_________________
Australian 2015 Featherweight champion
UK 2016 Gladiator champion

ok cool ill go the 18 v i have watched the videos angus put up there really good i was thinking the same for the armor withe the steal on the front now i just wait till pay day rolles around and get started
Thanks again

Yep go with the kmart 18volt drills they have all metal gears…thats what jules is doing on Pickasso for the sydney event. Our theory is run them on 4s lipo 16v (undervolted) so there is less chance of them exploding in the first battle. If you don't run the drills at their maximum they have more headroom before the brushes get hot from continually stoping starting and braking especially with big impacts happening all the time. Even though they will run a bit slower…its kind of safe to say reliability is better than speed.

Also if you are going to be welding a frame. It might be cheaper to just make the whole robot out of steel box section or steel plate. 3-6mm thick is good for armour. Also maybe for your first robot just build a reliable two wheel drive brick or wedge. Thats what Tim did for his first robot at 2014 nationals and he won.
_________________
Miles Blow - Julie Pitts
www.mulesfilm.com.au
www.wombokforest.com.au

-Pickasso- Vivid Sportsman champion 2015

Unless you have a source of cutting board or other UHMWPE just laying around, it is likely to be cheaper to just use metal and weld the entire thing. Regardless of the thicknes of plastic you use, there is a decent chance you will need to replace part of it during a full feather event like the nationals. Demon can get through 20mm of the stuff in a few seconds.


It can work, I have never had my internals eaten by a robot and most of mine are made out of cutitng board between 12mm and 30mm, sometimes doubled up with an average thickness of around 42mm. I end up spending about $60 a big event on armour that is replaced, even more if I get fancy and go polycarb.
Steel is far harder to replace mid event if you do go a thiner plate for weight and get a breach but should need less replacement.

Regarding Drive.
The one downside of the kmart 18v drills is the RPM was 550 vs the old DSE of 900 RPM. Undervolting would result in a slowish robot but far better reliablity. When you have an active weapon this slower speed may be more than acceptable to get the reliability. A call to make.

The reliable brick is always a good option. If you wished to be more adventerous, design your reliable brick to have space + weight for the active pnumatic spike weapon you are thinking of. That way if the weapon fails or the pnumatic system doesn't quite get finished, you still have a tough brick to anoy everyone with.
_________________
Remember to trust me, I am an Engineer.

http://www.youtube.com/watch?v=rp8hvyjZWHs

Also, I would just point out - you said HDPE cutting boards, don't buy actual cutting boards, make sure you buy the HDPE sheets if you're going that route.

Ellis (Tormenta) used cutting boards for Tormenta 1, and those ended up being really brittle https://www.youtube.com/watch?v=rW5bR4FWVMM

I would just go for a welded steel box as others have said though, as already mentioned Demon can get through 20mm of the stuff, and Decimator went clean through 20mm on the front of another roboteer's machine when Glen brought it over here for our championships... and that's just one machine! My first competition machine, Hardwired 2, was a 7mm (well, 2 layers of 3.2-4mm) hardox 450 brick, and after 2 events with numerous spinner fights it's still good enough to throw in the ring again. You won't need 7mm, but it proves the point and I've still got an extra 4 1/2kg of weight left over in that, so you could easily design something like that with an active weapon.

Depending on your budget, you could have a welded steel box with HDPE or some other kind of plastic bolted to that as disposable armour, or even wood (it's cheap and easy to work with) then you have the best of both worlds in terms of fixability and strength. The ablative armour should absorb most of the impact, and it's got a rigid steel endoskeleton to keep it all together!

ok guys u have given me a lot to think about i think i will go with the brick type design and maby have a couple of motors spare just incase i am going to try welding up a metal frame in the next few days i have thourght about makeing it so there are small bracket on the inside the would hold the plastic sheets the have metal sheeting over the top of that maby a few spikes on the front

http://i.imgur.com/PXAhACO.jpg?1[/img][/url]

ok so i was think of having four wheels bgut only 2 drive wheels the other 2 would only be for stabillity has anyone done this i only see bots with 2 wheels or with 4 wheel drive.
whould the extra 2 whells reduce the friction on the ground and improve stabillity or would they just make turning my difficult has anyone tried this before
or i was thinking of using a caster wheel in the center at the front just to reduce friction but once aagain has anyone tried this are casters to fregille and just going to get broken and slow the bot down

Thanks

sorry for my terrible spelling today im not dumb just cant type to save my life some days:P

Bots use tank steering so un-powered wheels make turning more difficult when they are dragged sideways. Caster wheels can work but they are usually a bit too fragile, particularly in bots with spinning weapons. You also have to consider what happens when the bot gets flipped; it would need casters on both sides.

Bots with four wheels and motors have the advantage of being able to drive and steer after losing one or even two wheels. In a two wheel bot, once you lose drive on one side its game over.
_________________
Australian 2015 Featherweight champion
UK 2016 Gladiator champion