The Riptide Beetleweight Chronicles

Thought I might as well set up a thread detailing the builds of my upcoming beetleweight machines, got 3 (technically 2) on the go at the minute, and I'll keep this updated with progress of the lot! Will probably edit this too when I have pictures of them all in progress.

The first one I'm building is a 4WD lifter with possibly the biggest drive motors you've ever seen in your life. May or may not be an exaggeration. I'm calling it 'Unmitigated Disaster' and it should be... well, an unmitigated disaster. Should be nice to drive about though. 20mm HDPE around the sides for armour, 2mm hdpe base and maybe doubling up for the lid. 3S/4S battery, standard 10a escs and some kind of servo on the lifter. Probably will be pushing it for weight, but I'll cross that bridge when I get to it!

[picture here]


Second is a horizontal bar spinner, Abandon, which will be an aluminium bar on aluminium bulkheads, aiming for about 10,000rpm on a 180mm bar, 400-500g monster. Should cause some pretty nice dents! Got a vague list of plans for components, but the only constant throughout them are the ebay gearmotors, looking at some sub-1000rpm ones to keep speed low as I won't need lots.

The third one, 'Tell It To The Cleaning Lady On Monday' (hopefully someone gets that reference), is actually technically still the second one since I'm just doubling up on bulkheads and basic structure, though it will have a single tooth bar, still at 400-ish grams as well as hopefully somewhere in the region of 15000+ rpm if my calculations work out right on the motor I've gone for, and 1200 RPM gearmotors. It will be utterly ludicrous and wholly hilarious for the three seconds it stays together for before ricocheting off into the distance, never to be seen again. Probably.



Getting started on the first of these tomorrow, so will post results - might have a go at CAD-ing up the other two from the sketches I have, but will definitely try and get those designs up in some form soon!

Because the cleaning lady has weekends off, right? ;)

Get building, I'd love to see photo's.

Bear in mind that the 10a BotBitz Esc's will only take 3s.

Not so true. I ran them on 4s. No more use of the BEC but controllers worked fine. Sabertooth was much nicer though.

Weren't they the old ones that went up to 4s or something?

Makes my life easier though anyway, running them on 3s is a lot easier than 4, probably...

Plans today were ruined by nature/life so I'll get started properly on this beetle this week. It almost certainly won't be in weight on first build, but hopefully will be able to refine it a little to get it into a battle-ready state at some point. Will try and bring this one to Stevenage where the HW champs are (?) in the inevitable absence of the other two bar spinners.

the 12a or 10a premiums were 4s. I got the cheapy ones because I'm a cheapy person.

It's the BEC (generic 7805 LDO regulator) that gets silly hot on the 10A's when running higher then 3S, if you unsolder it and use an external BEC/RX pack they can go closer to 18v (Naked Turtle ran them on 6S A123 for triggering solenoids on it's flipper)

Is there a guide to unsolder it?

Not really, just find it, and unsolder it.

That's not too bad then, I may do that anyways if I get a pair just to have the option. I have a pair of motors that I have no idea what the voltage are, so I think 3s may be the safe option haha

If you're talking about the motors you got from me they're 12v so they probably would be fine at 4s, even if they burn out the spares on ebay are dirt cheap and readily available. If you ever need a link to spares give me a shout.

Ahh that's alright then! Cheers haha

They seem big enough to take 4s reasonably well to be honest, but wouldn't want to blow them up straight away!

They should be fine for a few minutes at a time, I think the rule is motors are "safe" to be overvolted by 1.5 ttimes their nominal voltage, so those 12v ones should be okay up to 18v theoretically

https://www.youtube.com/watch?v=QvrmcoXCTbA

So I took apart my old PS3 and did a few minor modifications to the fan on it, seems to work pretty nicely and I think I might use this for something beetle-ey. Don't think it's got enough power for a feather or anything. Might still be too heavy for a beetle though too so need to double check the lot...

And that's all of today's progress, would you believe. Productive as always!

Why kill ps3?

Seeing the (albeit brief clips of) Beetleweights at this weekend's event has made me get a little bit inspired to start the beetleweights again, I've given up on anything too extravagant for now (I have no tools) so I'm going to build a mini HardWired 2 out of Hardox. Because, you know, hardox is too legit and whatnot.

It's going to serve the same purpose as its featherweight counterpart, in that it should be a supposedly low maintenance drive-all-day brick that will always be able to fight. Might end up doing a Beetleweight vertical bar spinner too at some point, but I'll see after this one's done. Previous plans were faaaaaaar too ambitious considering my skillset so I'm reeling it in a bit!

But yeah, basic plan is to make this entire thing out of 3.2mm hardox/stainless base, welded, and magnets on the bottom. It'll be tiny as well, which is why I'll be able to get it in weight hopefully. Was playing about with the idea of brushless drive, but I'll just stick with the 1000rpm Beetle motors that everyone loves, maybe on 4s or something. Characteristically huge battery too.

Will get sketches up soon where I can, but just imagine HardWired 2 but smaller and more poorly made, and that's not far off

Sorry to shut you down already but hardox isn't allowed as armour to keep things interesting (for active weapon users)

Just make it out of Stainless or Ti, you could go for pretty damn thick Ti if it's as small as i'm thinking.

Is it not? I keep hearing alternating things haha

Even if it is, I might just make one out of Hardox anyway and occasionally run it in whiteboards, I wanted to almost perfectly scale down HW2's relative idiotic-ness.

Thick ti would be possible, but expensive, that's the problem haha. It will be tiny though, so much so it'd probably almost pass for an antweight if my current calculations are right... It'll be tiny compared to the rest of the beetles, that much is for sure!

Think u can still use carbon steel/tool steel

If it is that small just use tool steel. Very durable and similar in weight.

Tool steel might be a nice idea.

Failing that, Stainless could also be very viable...

Quote:

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Originally Posted by Niels - Team K.a.L.M.

Sorry to shut you down already but hardox isn't allowed as armour to keep things interesting (for active weapon users)

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That rule is gone to my knowledge... it was only there when Swanny had the arena.

It sounds like it's just an encouraged rule rather than one that's actually enforced. Though I do understand the sentiment entirely...

That said, looking at the damage both Newton and RPM have put out (from what I've seen so far anyways) I'm sure Hardox won't be as indestructible as everyone makes out for long haha.

Still, I'll see what weight I have to work with, it might be that there's actually better options anyway, like Ti or even a tool steel shell... I don't know really!

But the dimensions roughly at the minute are about 140 x 120 x 35-ish. All rough, but I'm still trying to decide on a battery so I'm not too sure on the final ones... I'm looking for something with 4S, relatively high capacity but also compact. Thinking 2x 2S 800mah ones could do it? Probably a bit on the small side capacity wise though which bothers me...

Side question too, what are the dimensions of the motor and the gearbox of those 25mm ebay gearmotors that everyone uses? I was under the impression the overall length of those were 52mm, but not sure on the size of the motor itself...

And if anyone knows it, the reduction in the gearbox (for the 1000rpm one) and the shaft diameter on the motor itself? May be getting into strange modification territory here but if it saves a bit of space it's a good thing haha

The motors I have (incl. tabs and shaft) are 65mm long, 25mm diameter. And RPM does what it does with a blunt tooth ;)

Hmm, I may have slightly misjudged then and may need to make amends haha
I was looking at a brushless setup, with brushless motors in place of the brushed ones, still keeping that same gearbox (to keep things simple) but that'd potentially save some space and weight.

Adventures in CAD (alternative title: its an abomination, never cad again matt)

So, I finally decided to get off my backside and actually design something up. Originally a hexagonal Full Body Spinner, I mentioned it to Haz, and then jokingly mentioned it could be a triangular one because 'that would be bizzare'.

And thus, Bizzare Love Triangle was born. With a name suggestion like that, I couldn't not do it haha

Excuse the awful Cad-ing by the way, I'm naturally a radio/video sort of person so designing models of things is alien to me, and it shows... http://i1355.photobucket.com/albums/...ps84207eec.jpg

(and without the lid)
http://i1355.photobucket.com/albums/...psef9257be.jpg


It's powered by this battery http://www.hobbyking.com/hobbyking/s...Lipo_Pack.html

Drive is a set of 1000rpm gearmotors (ebay ones) with Botbitz 10A's, so pretty standard. No 4WD but 2wd with casters because weight and space is a problem.

Chassis I think I'll make out of 1/2mm grade 5 ti because that's light and what have you. Outer spinning disc and pillar in the middle will be aluminium of some kind. Hopefully 7075 or Alumec, but I'll see what price comes out at for that, considering I'll have to have it CNC'ed...

The weapon system is suspect to change, but this motor http://www.hobbyking.com/hobbyking/s...00kv_560w.html
With this esc http://www.hobbyking.com/hobbyking/s..._w_7A_BEC.html

and about a 2:1 reduction should get the outer shell spinning at about 7000 theoretical, probably 6000 actual. Or less. Either way, it's a large and heavy shell, it'll do damage at even 2000 rpm I reckon so it's still doing alright!

Now, the biggest problem I have at the minute is that this thing is literally huge. Outer diameter is about 380mm and that's pushing feather territory, May be a bit too big but I'll have to run it all through solidworks or something to figure out how much it'll weight. Guesstimations say it might be a tiny bit over, in which case I'll just cut into the shell a bit more, surely must be some weight to be saved there.

But yeah, new beetle build, should be fun and I'd like to get a FBS in circulation because despite the impracticalities for actually winning (the lack of srimech) they're hilariously fun to watch.

And here I thought Lynx was farking huge, it looks great though but I imagine it's going to be really tight on weight. Spin up time might also be an issue with a shell that diameter.

Yeah I have realised this now haha

Might end up scaling it down a little and going for antweight-sized motors instead of the beetle ones to be honest. Shell might get a 3:1 reduction too, I was worried about it but then I realised that similarly powered motors have been used (I think) to spin up heavier discs on heavier weight classes so might not be too bad. Might being the operative word there... I really have no idea what I'm doing, just wanting to put it together and hope for the best!