HardWired II

[overkill]

Well that's different then! Sensored outrunners should have excellent start-up torque and you can likely get more than you need from the 42mm, 1500w model. With it's higher KV, you can gear down a little more and get smoother steering as well. Given that my 95W inrunners can spin the wheels in Mr Mangle, 1,500W motors should be more than adequate.

[mrsam]

Loving that Sketchup model looks exactly how i pictured it would when you were talking about it at the champs, if you get this all working how you want i can see it being a properly good machine, tough as a brick, powerful drive and that disc on the front. Man stay away from Hatchet!

[Revsmin]

Yeah, 8S. Managed to shoehorn one of these into the back. You'd probably only get one fight out of it, but 8S batteries are big, and space was a concern. On 8S and 2:1 the disc speed is ~12,000rpm, and on that 150mm diameter disc tooth speed is ~215mph. That plus the wedge underneath means big hits every time. Disc weight is about 1.2kg. Weight-wise, I made a calculation error and factored in the weapon ESC twice, so realistically weight is about 12.8kg. And that's with basically the same shape as HWII, but half the thickness (all the way around) with 10mm HDPE instead of the stainless. Baseplate is also stainless, 3mm, which is 0.5mm thicker than the stainless base on HWII I believe. Put magnets in and it'd make for one heavy hitter! Drive-wise, this is the one being used, and if anyone else wants to use them I can upload the model to the workshop. On 5:1 top speed is as Matt said, 21mph. I reckon gearing down a little more for a bit more control and torque is a good idea, maybe just to 6:1. So yeah, should be a total brick with a hard hitting weapon and decent rambot drive as a plan B. What's not to love ?

[Eventorizon]

It looks just like I imagined it too. Space is going to be tight but I guess you are used to that.

As for the Lipo, you should only be doing 1 fight on a battery anyway. Conker 3's drive can last about 6 minutes but the weapon will die after about 4 minutes. They both cut off when the low voltage cut out activates at 3.5V, above the minimum 3.2V with a bit to spare.

The battery should be sized that you can run flat out with everything for 4 minutes; 3:30 if you are feeling frisky. Else you are carting around more weight than you need too and taking up more space. Of course you need a safety margin, hence the extra minute but by the sounds of things that 3.3Ah 8S should do it just right.

EDIT: where is the safety link going btw?

[Revsmin]

Thought of how I can do scale in Sketchup

[Flag Captured]

Aye, definitely Nick! Looking at different options still to see what'll be the best, maybe a 2/3-stage with faster motors would be better, but I'd just worry about space. Still, that's what designing's for I guess! I'm probably going to limit the output on the transmitter side, 2kw is a lot for drive, it's nice to have but I have a feeling it'll not be quite as controllable as I'd like. Still, if I can put that power down on a run up, that's going to leave a very nice bite, and should have plenty enough torque to push things about if needs be, or at least it will in theory. At least I'll have the magnets to help that out! It's nice to have that extra power there though as a 'if worst comes to worst' type thing, since I really don't know how it'll perform in practice!

Sam, it looks awesome doesn't it? Jarvis has done a heck of a job! Hopefully too, would like it to be able to cause a little more damage and carnage next year! Hardwired 2 will still be the relentless brick of the two, I fully intend to make that 100% reliable and indestructible but I think HardWired 3 will become my main competition machine. I'm actually looking into making both machines run the same internals so that I can perform an easy switch in case there's an issue, but I'm not too sure yet.
Big thing this year is going to be spares, I'm kind of going into the unknown here with the brushless stuff - granted, it's somewhat proven in battle, but the last thing I want to do is damage an ESC and have to forfeit the competition. Even more so because spares of anything will be much harder to come by than your bog standard TZ85s or Speed 900s, I'd assume.

Cheers too Jarvis, I can't remember stats for the life of me! May look at battery alternatives (not that big a fan of Zippy but there'll certainly be alternatives!) but on the whole they are pretty scary stats. 6:1 sounds good too, though I'm tempted to see how tests go with HW2, will see how that handles the motors with magnets and see what gear ratio would be optimal. Probably will end up being 6:1 though, no doubt. If I can build it well, it might be in with a shot of actually qualifying this year haha!

[Flag Captured]

Alex, safety link I'd think would go on the top similar to how HardWired 2's is, but I'd like a link door or something on it this time so NST can't tear it off again haha! 3.3ah should be alright, definitely looking at a slightly higher discharge though, max amps for the motor is 60 a side, and for the motor it's 128 so 220A in total, but I want to just have plenty of space with that. Would be fine, I bet, but I just like to have that little bit of insurance, with me being a newbie to the sport and all!

And Jarvis, that Cola can should be underneath that disc - I'm a Pepsi fan Very cool though for seeing the scale of it all, looks pretty small with a cola can next to it!

[mrsam]

Matt have a look at the Optipower Lipo's as i've heard people say really good things about them, there's a discount for FRA members as well which helps to soften the blow i think it's around 30% but not entirely sure. I think you'd be fine with 3.3ah as well, if you're running a spinner and your new drive system i imagine you'll be charging after every fight anyway.

[Ellis]

Looks good guys. I'd worry about that battery, though. Zippys hardly have a good track record. You'd be better off with a battery that can definitely deliver (basically Optipower, yes I'm a covert).

Also, I think 8s is way overkill. You really don't need a motor capable of putting out 4000w (!) to spin a 1.2kg disc. I have about 1500w (about 3:1) on tap and it spins my little 1.8kg drum to 10,000 as fast as I can move the stick. 720 is also on just 5s.

2 teeth on a 12,000rpm disc, at an unrealistic-for-the-maths 10mph collision speed and allowing for real life, you can hope for at maximum about 6mm of bite, which is really not a lot for a best-case. A single tooth will help that of course.

Hardox front end may actually be more trouble than it's worth next year. Takes one hit from any vert worth its stuff to bend 3.2mm and barely slow down now. You may do better to have something cheap and replaceable that can be bent back at an event or just replaced when it's too mangled. Saves weight too.

I'd focus on making the core of the bot (inner bulkheads, weapon shaft setup, structural (back?) plates, etc) as strong as possible, which can be achieved by downsizing motors and LiPo to gain weight freedom. Could even get a heavier disc in there.

[shakesc]

Downsizing of motors, heresy I tell you!

Overall the design does look to be coming together nicely

[Flag Captured]

Yeah, Optipowers are definitely going to be purchased for my machines from now on - they're very good! 8S may well be too, I agree but I'm aiming for OTT power, maybe it's slightly the wrong approach but still. Was tempted actually to run a single tooth disc on a 1:1 ratio from the motor, but I don't know if that'd be a little too fast... Hopefully the torque behind it would mean it'd just carry on going after a hit rather than slowing down, which is what I was aiming for with that motor in particular. Probably don't need something that powerful, but I want to try and push the boundaries a little!

Plan is to go with a single-tooth at some point, with most of the weight on the edge, should be fun! I'd like to aim for 20mm of bite on the disc, again ambitious but it gives a goal to work to. Yeah, I agree with the Hardox sentiment, however there are potential improvements to be made to it in the form of higher grade armour or whatever. Failing that, thicker titanium could work... I suppose it depends on angles though, they're pretty handy on HardWired at the minute, any high risk areas could have extra panels on, or maybe even use HDPE over the top like Explosion does.

There's always refinement to be done, but it'll get there. Research into new types of armour could work too, I have a few ideas and I've been listening to other peoples' for inspiration so could have something even nicer for armour when if gets built!

[overkill]

The kinetic energy of a spinning weapon increases with the square of the rpm, so a single tooth disk at a 1:1 reduction should have 4X the energy and at least theoretically the same amount of bite as a two tooth disk with a 2:1 reduction. Please chose option B so the rest of us have a chance

[daveimi]

I like reading these big budget robot builds, it's the stuff I can only dream of! Keep going it looks great!

[RogueTwoRobots]

that Cola can should be underneath that disc - I'm a Pepsi fan

Good man. We're a bit of a rare breed unfortunately (or fortunately, as it means more Pepsi for us!)

[mrsam]

Finally other Pepsi lovers! I get an unlimited supply at work