haha true it was a bitch to machine! All-though the aluminium drum was just as good, just not as hard wearing against other big spinners. The titanium drums around the 4kg mark and spins at about 13500rpm

would be kinda odd seeing a drum in one of your chassis though, be interesting to see what difference the current draw was between a drum and a beater of the same weight.

4Kg is a bit too much for my bots; I only have 3Kg for the drum excluding the pulley, bearings axle and mounting. From what I recall, your drum has massively thick walls and is quite a bit longer than what my latest bot will need, so similar construction will probably get it in the weight limit.

With the aluminium drum, did the teeth use a T slot and how well have they lasted, any problems with them pulling out?
_________________
Australian 2015 Featherweight champion
UK 2016 Gladiator champion

The aluminium drum was only 3kg including bearings from memory, and the titanium shaft doesn't weigh a fat lot

the drum was machined from 3inch "grade 10 silicone impregnated titanium"... apparently, whatever it was its one of the toughest things the guy who does my machining has ever had to machine, and i had to get a T-slot cutter sponsored, as the only cutter capable was £380!... its got a bore of 40mm ish from memory...

Yeah the T slots in the aluminium are showing no wear at all, which i find amazing... but then there is a large surface area for them to push against....

what weight and speed are your beaters?

Interesting info! I thought that cutting the T slot would be difficult, but the £380 cutter is a shock. I am thinking about how I could make an aluminium drum; I'd have to pay someone to bore the centre and maybe do the bearing pockets and then I could mill the T slots.

The beaters all weigh around 3Kg to 3.2Kg and have a diameter up to 155mm. They will spin up to 9K but anything over 7K draws huge amounts of current and the batteries wouldn't last even 1/2 a match.

If I do an aluminium drum, I want to do a single tooth version with a tungsten counterweight like Touro Feather has. In the latest version of Shiny, the drum would only be 178mm long so I can probably use a really thick drum wall and still get down to 3Kg. The weapon motor does 19K with no load, I don't know what gearing and the final speed the drum might be.
_________________
Australian 2015 Featherweight champion
UK 2016 Gladiator champion

Its not looking good for the first drum design; with an OD of 124mm and a bore of 50mm (the largest I can go with the bearing diameter of 52mm), the aluminium drum weighs in at 4.5Kg.



The teeth are 19mm square, I didn't bother to work out their weight given how much the drum weighs. I can always reduce the diameter but the smallest is about 114 mm. The bore can be increased but that means using end caps for the bearings and that starts getting complicated and less reliable.
_________________
Australian 2015 Featherweight champion
UK 2016 Gladiator champion

Thats what I discovered when I tried to make a drum for C3. The greater diameter makes them unfeasable for the same weight as a whisk. I think Drumroll's is about 90mm and 720's is 98mm, nowhere near the 165mm of C3. I don't know how big Shiny and Mr Mangles are but I assume they are similar to C3

The beaters are all around 150mm and 3Kg. I can use a smaller diameter drum as it can be mounted further out but there is a limit: the pulley is 75mm and the bearings are 52mm wide so the drum has to be wide enough for the tooth channels to clear those features.

I might be able to swap to a timing belt to get the pulley smaller but its not going to make a huge difference. Perhaps the next thing is to estimate the KE of the existing beater VS the smallest drum; the diameter is part of the equation and since the beaters have more of their mass right out at the perimeter, their KE might not be so bad at lower RPM.
_________________
Australian 2015 Featherweight champion
UK 2016 Gladiator champion

The wedge:

The new anti horizontal spinner wedge is all cut out and fitted for welding:



The face is 7.3mm thick and has a reinforcing strip near where most spinners will hit. the mounting brackets are 5.6mm and once its all welded up it should be very stiff.



When the wedge is mounted, it will ride a couple of mm off the floor so it can deflect downwards and absorb the energy from hits; I'm hoping it will also be able to launch some spinners with its low angle. The front of the bot will ride on a pair of UHMW slides mounted on the main body. They will have lower friction than the Ti forks so the bot can turn faster.

Is that shiny enough for you Miles?
_________________
Australian 2015 Featherweight champion
UK 2016 Gladiator champion

bah just a bigger target right glen
_________________
Creative Instigation - Build Something Awesome!

https://www.youtube.com/channel/UCTuWeJ4OrAcsmjKir9L4JNg

https://www.facebook.com/CreativeInstigation/

Nice edge for horizontals to get a bite on but I would be guessing Bender wont get the opertunity as its elastoreactive amour is vulnerable to vertical weapons.
_________________
Satisfaction is proportional to effort and results.

Maybe, but wedges often win events just by wearing down their opponents - just ask Angus. The plan is to use the eggbeater as much as possible and have the wedge in case the spinner can't be repaired. I have never had a defensive wedge bot before, so we will have to see how the strategy evolves. The wedge would have come in really handy last year when Mr Mangle and Decimator had their first fight - after both weapons were KO'ed, I could have just bolted on the wedge and kept going.
_________________
Australian 2015 Featherweight champion
UK 2016 Gladiator champion

And yes, Bender's tire armour is too good a target to ever think of using the wedge
_________________
Australian 2015 Featherweight champion
UK 2016 Gladiator champion

Right; never thought of your point of view of always having the spinner.

I have fought as both and as the spinner desperately trying to get the decisive hit in as I am repeatedly wedged into the wall and as a brick just slamming into the opponent spinner trying to break it.

Different feeling altogether.

You get another feeling with a thin skinned control bot, 2 actually depending if you’re trying to stack a pesky brick or risking destruction KE spinner wise.
_________________
Satisfaction is proportional to effort and results.

Testing:

After some heavy-duty 'testing' (Steve, do what ya gotta do!) Mr Mangle and Shiny are 90% ready for the Nats event. Shiny ran well until the flat battery I accidentally used went REALLY flat and the electronics had a brown-out. Fortunately, the pack balanced & recharged so I take back all the bad things I said about Turnigy Nanotech batteries! The weapon motor shifted in its mount, causing the belt to partly turn inside-out; it didn't break or lose it's grip but was wearing down fast. I have a couple of quick fixes for the problem so it shouldn't happen again.

Mr Mangle as also running well; it had a driving problem on one side to start with but that seems to have been some junk stuck under the bot and eventually the problem cleared itself. Mr Mangle still isn't driving quite as well as Shiny, which is weird since they have the exact same drivetrain, weight distribution and radio programming.
_________________
Australian 2015 Featherweight champion
UK 2016 Gladiator champion

Saturday:

For some reason, Saturday quickly turned into brainfart day . Everything I touched went wrong so its best if I stay away from power tools for the rest of the day.

The new charging station is taking shape and I managed to mount the chargers after drilling holes in the wrong places. The chargers don't have any mounting points and an uneven base, so I made MDF mounting blocks with screw anchors to hold the chargers on a mounting board:





By using double sided tape and an alignment guide, it didn't matter that the mounting blocks were not in the right position. The 3M VHB 5952 tape deserves a special mention; its like regular VHB tape that has been dipped in super glue and infused with ground-up black holes. Once its stuck down, nothing will shift it!

New welding table:

With some new project ideas coming up, the old welding table needed an upgrade. This folding table from Hare & Forbes is a bit lightweight but is a huge improvement on the old ironing board I was using:



It might be worth adding a 10 or 12mm steel plate top; getting it plasma cut shouldn't be too expensive and will make the table WAY more rigid.

I also bought a set of small magnetic clamps. They are really versatile as they can position parts at 30, 45, 60 and 90 degrees and have plenty of holding power for such a small clamp:




Spare Parts:

With the bots mostly sorted out for the next event, its time to make a few spares:



Just in case....
_________________
Australian 2015 Featherweight champion
UK 2016 Gladiator champion