HardWired II

"Precision engineering" I laughed so much
Looks just like my new bot too!

Looks like, but is probably built a LOT better than this monstrosity haha!
I don't think I did that bad considering time/money/tool constraints, but the next one will at least look passable!

Going to try and make something a bit more robust internally, then pile wood on the outside so spinners have something nice to chew on haha

This is so awesome!! Pls can you put pictures up of the insides!

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Best picture I have! It's extremely basic, just a pair of drills, drill battery and receiver. It's as basic as it gets, but it works I guess!

Not bad for a bunch of scrap parts I wouldn't say haha. Really won't last long in battle though! Do intend a rebuild with a (thin) aluminium inner shell, and a ton of balsa/ply round the edge to let it get battered, still be extremely cheap to do but it'll look pretty spectacular, especially at the spinner events!

Archangel Rises!

So, it's been a while since I've done a proper update, and now thanks to help from Alex (designing the bar) and Jarvis (Cad'ing up the machine), here's Archangel!

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It's a 200mm radius single tooth bar, powered by a Scorpion 5020 450kv on a 4Ah Optipower 6s, 1.4/1.5:1 ish ratio leading to about 7000 rpm. Tip speed is upwards of 230mph, and with a sharp tooth it'll cause plenty of damage! Rather hoping it'll tear holes in Hardox, definitely seems like it has the potential to!
Drive at the minute is 775 banebots, at present 16:1 on 124mm wheels but I'm looking at maybe going 64:1 because magnets, but I'll get to that in a minute.

The black material is all HDPE, on this Cad it's 10mm but I'm thinking that could be upgraded a little, potentially, if not reinforced with some other kind of material. The rust coloured stuff is 3.2 hardox, but bent into shape rather than welded (though could still be welded, just helps to keep the strength up) and I'm maybe going to reinforce that at some point with HDPE too if needs be. Bulkheads are aluminium, looking at 7075 or just some kind of good grade, would like alumec but I'm told that's really expensive... heavily machined of course, given the size. Fixed 20mm shaft, seems like a far better option than a free one in this type of design at least!

The base is 3.2-4mm stainless, which will have magnets dotted around the wheels, I'd like to say something like 100 kg of magnets would keep it stable, but that'll be a heavy strain on the motors and will probably cause problems against other spinners, so maybe an absolute maximum of 20kg around the wheels, keep those on the ground, or at least keep the machine from tipping when it turns! I could alternatively go with maybe 100kg and have 64:1 motors, but that'd lead to about 6mph top speed which wouldn't be that fun. I think it's going to be more a case of trial and error than anything...

But yeah, that's Archangel, there'll be plenty of little refinements and adjustments to make as the build goes along I'd bet but that's the bulk of the machine. Won't be long until I can start building it, hopefully!

Big thanks again to Alex and Jarvis for the help!

I like the design and the bar looks deadly, it would get good engagement at RPM and bar diameter aswell.

Thanks! It's roughly based on Electric Boogaloo from the US, that seems pretty scary so why not haha

I think Alex said to me that the bar has 60mm of bite at 7000rpm, which would be insanely scary! good news too as it means that I can up the voltage a little bit at a later time if I feel a little bit idiotic to get even higher speeds with a still usable bite...

Yeah its a pretty successful robot from what I've seen, nice to see a vertical bar too. And at 7000rpm you probably wouldn't need magnets at all, the robot should be fairly stable with the width on the CAD model, I'd also worry that at 6S, the motors will be worked too hard with the reistance of magnets on top of the over voltage, thats assuming they are the 18v ones.

Very! I believe it was ranked 3rd in the 2012 Combots cup after only ever competing at Robogames before or something? It really does hit hard that one! I believe a lot of it is in the bar design, it's a weird kind of single tooth, quite different from this one though I hope they perform similarly!

Thanks, I never thought of that! I'd have just assumed they'd kick out more torque to deal with it! Still pretty new to motors as a whole haha
It might be that I either go for a split battery (5s and a 6s) or see how it goes without magnets after it's built. It can run inverted so if it does lift it can get back over... just don't want it to be near enough uncontrollable! They are the 18v ones too, I've been having a look to see if there's the equivalent motor in 24v but don't seem to be having much luck.

I think magnet-less could work too but may need simply to get good at driving it... I might leave at least a little bit of magnet downforce in there to reduce the likeliness of it lifting, but perhaps nothing as substantial as it was. Like I said earlier, it might end up being a trial and error sort of thing, see how it copes with everything. Might be worth trialing a set of Banebots drives on 6s to see how it copes in that sense, I know if they stall at that voltage, I can say goodbye to my speed controllers haha!

Archangel has a great design and will pack a huge punch. You might want to reconsider the weapon motor though; the 5020 is meant to run at 12S and on a 6S pack, its only going to produce 942 watts (1/4 power) and top no-load speed with a 1.5:1 reduction of 6,600 rpm. You will need to go to about a 10S, 37V pack to realistically get the bar spinning at the speed you want, or find a motor with at least an 850KV rating to stay with 6S packs.

Without knowing the weight and MOI of the bar its hard to work out the power rating of the motor needed to run it. Some of the best high KV motors I found are the Scorpion HKIII-4025-890KV Motor and the Hacker A50-8S Turnado V3 Motor - they may have the power & torque to spin that bar up with a 2:1 reduction.

I think the smartest thing is to use two 5S packs with a bit lower AH rating and then do split voltage wiring like I did in Mr Mangle. that will give you 5S to keep the 775 motors happy and 10S for the 5020 Scorpion motor. You could go with completely separate packs for the weapon & motor, but its likely to weigh more.