Bit of advice on my drumbot please

[RogueTwoRobots]

Hmmm, 2WD or 4WD? I have to admit, the 4WD looks waaay cooler and it looks a little Growler-esque but with a hulking great drum in place of the jaws. In addition to that, if your drum breaks down in battle, 4WD could benefit you more when you have to resort to ramming people around.

Other than that, I don't think there are any advantages of four wheels over two. With two wheels, your turning (particularly on the spot) will be much quicker which could serve you well if you need to spin round quickly to attack someone. As mentioned, it'll also be lighter and more compact, leaving more weight for armour or weapons. Your pushing ability will be slightly less but probably not that significant in the grand scheme of things.

If you can adjust the design slightly to accommodate invertibility, I'd strongly recommend it. A self-righter will take up weight and be a lot of work (thinking back to how many problems Dave had trying to get 360's one working) and for me, just stopping fighting when turned upside-down isn't appealing. Just my opinion though
Then again, it could end up righting itself with the drum anyway; that's what Gary discovered with Boner at the 2010 champs with the Speed 900s in. If he spun it up while upside-down the drum teeth would hit off the floor and gradually bounce the robot a bit higher with each hit until it flipped itself all the way back over.

Regarding brushed/brushless, I find the Speed 900s are only really effective if the drum is over a certain weight. They worked great in old Drumroll/Boner because the drum weighed 4.2kg, but my current one weighs 2.1kg and there's just not enough energy in it to do any decent damage. I know the obvious fact is that there is a lot less weight in the periphery so there's not as much energy built up to transfer, but with more speed comes more energy, so brushless motors are probably the better option for the lighter weapons. That's what I'm going for anyway; seemed to work well at the 2010 champs until I busted a tooth

[calumco]

quick reply cause im on my phone, but thanks jamie bin talkin to dave and recon im going for those big wheels again i got a decent speed too on only 8.4 volts at the uks. having them as far forward as possible shud hopefully stop it having the same problem as last time D:

[RogueTwoRobots]

jamie bin talkin

Am I the new leader of Al-Qaeda or something? :shock:

[mattsdragons]

Apparently so

[typhoon_driver]

2 wheels, I'd go for the small ones and have a dummy set on the top side pressed against the powered two to run via friction upside down. Get a decent brushless setup and that drum will fly.

[calumco]

LOL jamie haha

gary i could kiss you..... but i wont, but still thats a brilliant idea! means i can make the bulkheads higher meaning the drum can run freely upside down aswell as it wouldn't have been able to before and the robot can be alot shorter as all the internals can fit in vertically above the motors got a pair of 100mm wheels with bearings inside already..... propper job!

nylon came today aswell, so hopefully start making tomorrow/friday

[RogueTwoRobots]

Ah yeah, that's something I forgot to add yesterday. Smaller wheels seem to be more reliable with drum spinners (from my experience anyway). Drumroll had 75mm wheels, Drumroll II has 125mm wheels; the greatly-increased speed of Drumroll II is handy for darting about the arena, but there is much more force being placed not only on the drill shaft, but also the nuts melted into the wheels, especially when the shocks from impacts are going through your robot. I'm currently on my third set of wheels with Drumroll II and am planning on making a new set soon. The nuts began to pull out of the first set (home-made), with the second set one became partially loose then got jammed on (the pair I used at the champs) and the current set, while holding up fine in that respect, don't quite have a level of grip or robustness I'm happy with. By comparison, the old Drumroll ran the same set of wheels for four years without any problems.

[calumco]

surprisingly after just 5 and a half hours today i've got something which resembles a robot......

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Going for lipos for the drive and drum as i wana save as much weight as possible for hardox wheel guards and lower back armour. i may even cut the top down so it slopes down towards the back to save on nylon weight as its heavy and to get it even more compact but ill see how i go on space inside. suprised aswell because nothings gone wrong so far or been mounted wrong lol i must be learning after 3 years finally

next job one day next week is to get the speedos mounted, make my own ali bracket for the drum motor and wire most of it up and hopefully give the drum a slow spin up and drive about

[Mouldy]

Make sure you chop those teeth of before you spin it up lol

[calumco]

Did some yesterday, cut the bulheads down on the top so that they are sloping down towards the back and its looking pretty cool now sorted out the motor mounting, and cut the teeth off the drum but the drums now totally screwed still badly off balance without any teeth on now im guessing from the welding and weld replacing stainless on the drum and so forth so its once again off balance. thinking about sending it to someone to get teeth made but i don't think it'd be easy balancing it so i may get tom or kenny or someone to make me a beater style weapon instead of the same dia. but pics to follow soon.....