mounting wheels

This is our sumo bot which runs 2 wheel drive, but is a 4 wheeled bot.
The spare corners just have a simple axle running through the wheel .. in this case to stay under 3 kg for sumo rules it's just a bit of 12 mm nylon pneumatic tubing

Rebuild

well it's taken a long time.. but I've finally got round to fixing things. I dallied briefly with the old heavyweight carrot, and ran it in the FRA championships (see next post), and remebered why I enjoyed playing with feathers so much. They are samll and easy to carry, don't hurt your back or your wallet so much.
So my big problem was getting the time to visit Plumpton, my old college to machine up some new bushes.. so I asked the FRA forum, and Trev Wright came up trumps, and has machined me some lovely little bushes. In the mean time, I've looked at the power problem and procured some slightly meatier batteries Sayno RC2400, 24v... and squeezed a set of curtis 70 amp controllers into the frame.. which to be honest is a lot less messy than the old electronise with all the relay cabling.
So I have to fit the bushes now and reassemble the drive trains, and then go for a bit of a test.

Modelworld update

The gearbox repairs went ok, and even with desperate amounts of slack in the system, Metahammer ran ok.. well sort of..
The new batteries mad ea big difference, giving us plenty of zip, and powering along enough to push scorpion jnr and pillow torque.. though they faded after a few minutes and that was that.. I need to add another pack to bump up the Ah rating, I could work out what the motors are using but can't be bothered at the minute.
AN investment in another battery, and 4 bearing blocks is called for..
not sure when the next outing will be.

Model World 2006

Here's Meathammer with its scoop sitting on the bench charging quietly before some "football"

and here we are in the air after being shunted by KR3.
We failed the assualt course miserably, too much slide and spin.. cutting in the dual rate helped.. but too late.
Did better on the sumo table, won the first 3 bouts, but when we were up again against scorpion we were out shoved.
Playing football has broken a set of plastic gears in one of the gearboxes, which I can fix... but one of the pinions has come loose too. not sure If I can fix that in situ. The driveshafts are desperatly in need of more support, and I think I'll have to add some bearing blocks.

ready for action

Just put the finishing touches to Meathammer
The whole setup works quite well.. I'm off to modelworld to run it through it's paces a couple of times.
The weak bits look to be the drive shafts, which I'd like to bulk up to at least 20mm and have some better bearnings for.
The battery packs are also a bit weedy, but we'll see how they last, and may invest in a few high output packs.
Of course it could also really do with running the 4QD 35's or 60's instead of the electronise speedies.. but we'll see how it performs and make amends.
Since I took this phot I've added a hinged scoop, so we can get under other feathers... it's a popular design in the states, should work over here.
I only need to wire in an LED to show power and then we are ok to roll.

The electronise speedos fit quite nicely, and there's plenty of room for the 4QD's if I choose to swap over. I've run it up at 12v and 24v, and it sounds a helluva lot better at 24v. The motors are cheap 12v jobbies, so overvolting them to 24v may get them warm. The other decision is what batteries to run them on. I have a couple of 12v NiCad packs i made about 3 years ago... but they are only around 1400mAh.
I am tempted to buy a couple of 8.4v sub C 1900mAh battery packs from technobots, and see how it performs at about 16v. It's just a cse of how h=long the packs last really.
There's enough room in there for 4 packs, so that would be 3800mAh. The big bot used to get by on 15Ah, so just 12kg shoukld be ok on 3Ah?
We'll see.
I've drilled the hubs, and just need to weld them up now.

Ok I went the easy route and trimmed down the plastic housings and araldited them to the cages. the motors mount up ok, and I've given each of them a test run and they all seem to run smoothly.
The next step is to wire in the speed controllers. I have the electronise to hand for starters, as I only need to stick a couple of crimp fit connectors onto the wire to get things happening.
Then I need to make the wheel hubs.. Might get some of it done this week, but I really am in no rush at all.