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Decimator - Team Demon - NSW (download limits beware)
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Eventorizon-GB



Joined: 15 Nov 2013
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Location: Ripon, United Kingdom


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One problem. They cant go to Birmingham because apparently its a Muslim only city and you will be beaten if you try to enter, according to the Americans: http://www.bbc.co.uk/news/uk-england-30773297
[A joke at the expense of the Republicans]

Post Mon Jan 12, 2015 11:56 pm 
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Nick
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That was hilarious! Americans are known for being geographically challenged but that takes it to a whole new level Smile As long as we get the bots halal certified, everything should be OK.
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Post Tue Jan 13, 2015 12:45 am 
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Eventorizon-GB



Joined: 15 Nov 2013
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Location: Ripon, United Kingdom


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quote:
Originally posted by Nick:
As long as we get the bots halal certified, everything should be OK.

That actually had me clapping out loud! Bravo!

Post Tue Jan 13, 2015 2:34 am 
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Glen
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https://www.youtube.com/watch?v=KGC0cm2IWLg

Seems to do the thing. Just seeing how it runs with the old blade and my super duper rebuilt scorpion motor. Goes okay off a crappy old zippy 5s.

Seems off balance which is odd, as the cad is good. Maybe its some cumulative imbalance through the hub and motor/pulley set. With the wheels bolted to the robot it barely moves (was just held up with clamps in the vid) So its most likely only a tiny bit off.

Need to build a proper balancing jig for my weapons though, have been meaning to do it for some time.

Anyways. No more postings in this thread till i have a batch of progress ready to be posted. Getting there Smile Hopefully in 2 weeks it should be nearly done.
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Post Mon Jan 26, 2015 11:05 pm 
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miles&Jules
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That looked like a scene from a movie…epic lighting…robot good to Very Happy
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Post Tue Jan 27, 2015 12:14 am 
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Glen
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Build report incoming - better late than never as they say. Typing it at midnight while trying to stay up long enough to get back in sync with Sydney time so excuse any typo's. it would seem i don't travel well at all, ended up sleeping for about 30 hours over the weekend lol!

THE PLAN

Given the lack of running time the robot got at the nationals it was hard to say what needed to change aside from some obvious things that didn't work. So many of the revisions were done on assumptions of what the UK arena might favour.

There were 4 main things that needed redoing after failing dramatically at the 2014 nationals.

The first was the scorpion weapon motor. When the disk bent, it caught the belt and ripped the motor off its mount. Having pulled the stator off it was obvious there's a fair bit of room for improvement. The 4x m3 holes only have about 3mm of thread depth and the tube itself is really weak. It's not a strain to bend it by hand.



One goal for the rebuild was to replace every aluminium part with high grade 7075, enabled by finding thyssen krupp aerospace who sell it for a very reasonable price. So, redoing the scorpion stator tube allowed me to solve many problems like the weak bolt holes and general weakness of this part while using the strength of the 7075 to keep it all fairly light. The robot was close to the weight limit before the changes after all.

Next up was the 775 motors for the drive. One of the magnets fell out and burnt the motor up. The cause is fairly obvious after taking apart all my stash. The U shaped spring clip is massively variable in size and tension, they must make them by hand. On at least one of the motors i was able to slide the clip out with my finger and on the other two i needed to wrench them out with pliers. I would say that the loose clips allow the magnets to drop out on big hits. That would explain why some motors rarely fail and others do without much provocation.



Glueing them in is an easy fix, but getting the motor end caps off and back on while keeping everything running smooth was looking to be a bit of a pain that needed a fair bit of R&D before i got it right.

Third, the disk sucked (try say that fast a few times, hueheuh). It was a horrible design done in a night with no optimisation. Given it was only 12mm thick, there was no strength to it and Mr mangle wrecked it instantly. Giving up some diameter to make it thicker was out of the question and i was very keen to try a spinning bar after all these years of having a disk on demon, so that was the plan.

16mm was the next thickness up from 12 in bisalloy 500 grade so i worked around that and the existing robot dimensions to come up with this design -



Working backwards from the minimum design speed of about 5000rpm and drive speed gave the values for the maximum bite which drove the dimensions of the counterweight. All in all the design evolved pretty quick. The final one was only about the 3rd revision. Was happy with the design, looked quite organic Smile

Based on some rudimentary calculations, it should be over 4x as resistant to bending as the old setup. Probably even more so as the hub was remade from 7075 to accomodate the new thickness which spaced the bearings apart a little further.



Only needed some small changes in width and counterweight size to make a 20mm longer one that i could use in our Australian arenas Smile With the flip outs, 3 way fights and pit i figured smaller diameter and fast spin up was probably more advantageous in the UK.

And finally was the Base and top material. Originally i tried 5mm HDPE thinking the flex would save the components from shock. That clearly didn't work considering the motors dropped magnets and the material just bent permanently anyway. the whole lot would flex when you put the robot on the ground too, not so good!

There wasn't much i could change in the time given, so took a risk on some proper 3mm carbon fibre that would be waterjet cut.. It would weigh the same or close to and hopefully be a substantial amount stiffer. Plus look awesome Smile

In addition to that was a rather busy period at work, building a few large items and the stress of having to plan not only a way to get the robots there but organise the trip from scratch having barely even left my home state before, then plan spares, tools and make it all fit in the baggage weight limit Shocked Shocked STRESS STRESS.

Next up, the build itself!
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Last edited by Glen on Mon Apr 20, 2015 12:56 am; edited 3 times in total

Post Mon Apr 06, 2015 12:58 am 
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Glen
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THE BUILD

Just a quick note, this is not actually in chronological order, but arranged to make following easier as i was jumping between making different parts. Hopefully it flows well enough.

Lets do dis

First order of the day is to actually bring the robot home. The astute of you may notice no one sitting near me. Ain't you ever seen a killer robot half on a train before?



Gotta disassemble some motors to harden them up.

Removing the backs of the 775 motors is tricky without ruining things as the plate on the end of the motor is paper thin. Using a super ground down flatblade tool in one of those ratcheting screwdrivers worked best. simply sit the motor, shaft down, on a table, then bend the tabs out, resting the screwdriver on the back of the shaft for leverage.

The tabs could be ground off as they wont be used again during re-assembly. The above method worked well for me though across 4 motors.



This is what the guts look like *ooo*



As for glue i wasn't going to half ass it with brittle epoxies and the like, research suggested two glues were the best - loctite 480 black max. A rubberised CA glue or uhu endfest 300. I paid the $60 for a bottle of it like a total sucker, but believe me this is the most bullshit strong glue you will come across.

Of course it also requires a $40 applicator. You best be joking uhu. Fortunately I was able to cobble this together using much more than $40 in metal. Effecient!



To test, The old broken motor + magnets were haphazardly slathered in the stuff and and no amount of levering, bashing or otherwise would get them off. For a coup de grace it was set upon with a hammer, bashing the motor can flat and all that happened was the magnets broke into chunks but remained attached. Good enough for me.

Hard to get a pic of the final product but the process is easy enough. Sand the can and magnet back, clean with acetone then smear the glue on and press em in. Wipe away the excess with a cloth soaked in acetone. There's an aluminium plug coated in oil that presses in to keep the magnets pressed outward against the can, you can see the plug in the previous pic.



Next is the tricky bit, getting the can back on. Took a gamble here but it paid off nicely. Essentially, the motor is sat in a tub of water then plate tig welded back on. With a super sharp tungsten, a quick press of the foot pedal fuses it beautifully. Levering the test motors end plate to death didn't manage to break it off, so I'll call that a success. Also used a needle to run a thin bead of uhu 300 glue around as backup. Very permanent now Very Happy

In order to get them to run properly there's a bit of a trick. First press the motor in a vice between two sockets to gently re-align the back plate. Inevitably it gets twisted a tiny bit in the removal stage, after that simply sit a current meter on the assembled motor and gently pry the plate with a flatblade screwdriver until it draws the least current. These ones ended up drawing even less than a brand new banebots. About 2.2A vs 2.7 of a stock one. Sounds much healthier too Smile




Next up is to rebuild the scorpion weapon motors and make a spare using the now defunct Demon's motor.

They get the freezer treatment and then it is just a matter of smacking the tubes out with a drift. Easy job despite the bemoaning of many on rc forums that they are hard to remove.



Grabbed a piece of 50mm 7075 from thyssen for the decent price of $23 and started on the new stator tubes. These will have a much thicker base, more bolts, deeper and larger threads plus the tube itself will have a thicker wall, all with the advantage of being made from a stronger metal.

Here's the first one being made. Unfortunately Glen poured himself a nice tall glass of DERP and didn't put a big chamfer on the base, meaning when i bored the bearing pocket on the reverse side the stub just fell off due to it being the same diameter. *dribbles*



Fortunately things are always faster the 2nd time so that wasn't too bad. Note the chamfer on this one. Just had to part him off then it's on to the new mount.



There was a sliver left from making the new weapon hub that was perfect for the brushless mount. Being concentric made doing the central pocket nice and easy in the lathe.

My bandsaw was being stupid so i used the slitting saw to cut it down. Glad i did as the saw does a fantastic job, requiring barely any clean up. Add that to the old book of tricks.



After fly cutting it to final size, that 7075 machines real nice.



You will notice a theme through this build, Laser cut jigs are used for EVERYTHING because i am ultra lazy now. Here is one such jig for cutting the slots in the motor mount. These are for the 4x start holes. There's a circular piece that locates in the bored hole on the other side




From that, the slots can be cut. I made a hash of it though. the finish sucks but they are in the right place and worked so eh. My mill spindle has a problem where it pulls down under load about 1mm. I'm removing the quill drive for the cnc swap so whatever. The stator tube is a perfect fit in the bore though. Good stuff.



On to my favourite tool for the holes. (haha ah eugh) 8x m5 bolts should sort it out this time.



All done Smile The tube had to get flipped in the lathe in order to bore the bearing pocket which took forever, as it needs to be 100% dead center or it will ruin the weedy bearings when its all assembled.



Was hard to get a pic (apologies), but the base of the stator mount is with liquid electrical tape. Dissecting the stock scorpion shows that the windings on the bottom actually touch this part on the stock stator tube which is a bit of a worry. It comes close on my versions but doesn't touch. The coating is insurance anyways. Check out how chunky the mounting flange is though. No more bending allowed!



All the spares ready to go. Spent $30 on new bearings for the motors to find scorpion has once again changed the design of the same motor so the new ones don't fit. Scorpion you really make me cri everytim :'(

The motors themselves are shimmed and everything as inevitably there is some variation in the stator height once the stators are pressed on. That worked well. Leaving some variation for manufacturing tolerances is never a bad thing. Note too the new motor doesn't have a grub screw ring on the bottom of the pulley. The press fit is so good it isn't required. That saved a substantial amount of weight.



After that my carbon finally arrived, AWW YIS. I had done a lot of shopping around originally. Dumhed was on a work trip to the US at the time so the plan was to get some dragonplate bought back with him, but sometime during, i found this place on ebay that was way cheaper and many said good things about the quality of the plate online. With a name like this, how could you go wrong?!

http://www.ebay.com/usr/happychoice2009?_trksid=p2047675.l2559

Annoyingly they didn't reply back or answer any form of correspondence for 3 weeks forcing me to look elswhere. Funnily enough they sent lots of threatening emails like 2 months later lol. What?

Around then big blue saw posted they could do carbon fibre cutting and had 1/8 carbon in stock, perfect! Got a quick quote and just went with it for the pricey total of $400 usd. Didn't have much time left so whatever.

Not accusing anyone of anything, but basically I think they didn't have the carbon in stock like their website seems to suggest, so the parts took a little while to get cut (about 3 weeks or so from memory).

The quality of the cut was very nice, however only one part was correct, to their credit it was to the mm accurate, like 170mm dead. but the other parts were wildly incorrect. Seems like the rest got rescaled from some arbitrary point. They were too short in Y and too wide in X from this random point.

God only knows what happened as it was only 2x dxf's for the 3 parts. Honestly wouldn't deal with them again but at least the parts were usable after some work.

The lid is too large all over except the wheel well on one side that pokes in too far. IDK...



The belt linisher made quick work of it though. And hand files sand carbon fibre very easily. Just sucked having to suit up to work with it though as the powder gets stuck in your skin and what not. Unpleasant. The fit was delightfully satisfying after though, clicking into place almost Very Happy Using the existing mounting tab holes made it easy to drill the ones in the carbon top plate. The original HDPE top plate was used as a template for the 8x bolts that go into the banebots drives from above.



The base pissed me off the most though. It was really off. This is probably the least off of the whole part.. the one on the right is way smaller, this meant it has less support where the mounting bolts to the robot go making me worried it would just break off. Luckily it never happened but not nice when you pay $400 for them!



In the end, by using the square notch as the x,y 0 point, then clamping both halves to the old hdpe base, the holes were drilled using the original as a template. I had to drill them myself as you can't waterjet a hole in CF this thick without delaminating it apparently. Have to predrill holes which is why only the link one was done.

All installed after much frustration -



Next is the link door hole. More laser cut jiggy goodness. This one clamps into the pre waterjetted hole




Same deal for the door itself. A 3 piece affair however. Having the carbon backed with MDF really cuts down on the delamination.




I'm not afraid to admit about 4 hours were wasted carefully aligning everything so that the laminations would stay lined up Wink OCD orgasm indeed.



Next on the list, these are the jigs for mounting the battery bay walls which are made from UHMW milled and screwed together with deck screws. The bottom one is to drill the holes in the base plate, the other is to drill the holes in the uhmw itself.



First one bolts to the existing holes in the back of the robot, The holes were drilled by hand as it was a bit awkward doing it in the press.



Next the 2nd jig is installed and the walls slotted in, then the holes are drilled from the bottom using the fresh holes done in the last step. That worked really well in the end. Everything was perfectly aligned.




With those mounted i could go on to putting in the holes for the LED and power link connector.

More mdf jigs! This one is for the link. Started by drilling an 8mm hole for reference, then hand filed the shape out from that with a square bastard file. In the 3rd pic you can see the flat plate the link, LED, fuse and wiring junctions all mount to. The piece goes into two slots milled in the vertical panels with 2x deck screws. It's very lego-ish the way it all snaps together Razz






I experimented with a tapered plug to cut a slot out in a press, which kinda worked, but deforms the uhmw a fair amount and filing it was easy enough so that idea was never pursued further.



Another jig for the LED hole. Drilled an 8mm hole through the CF then straight down into the UHMW plate to keep it aligned.



The weapon -

Trying to track down that material was a bit of a bitch. Many places stocked bisalloy or everhard (will post them up later), but getting 500 grade was tricky. Aaron later posted up a place that could have done it much better but ah well, you can't change the past Razz

In the end our old friend precision oxycut had a piece of just the right size. Cost was a reasonable $80. A huge thanks to my BFF Jess that drove to Newcastle to get it and bring it back down for me. Tru Luv <3 She wasn't too happy it weighed 30kg though and was filthy though. Oops



Wanted to have the blades waterjetted to eliminate any heat affected loss of hardness, so it was couriered to AWC in Queensland, who got the work done in record time. It was so fast I actually thought the package never got sent and was about to give the courier a serve!



Unfortunately they also did a proper shit job too. UGH. I mentioned specifically in the email the material was bisalloy 500 which they acknowledged, but seemingly they just went ahead and used the mild steel settings. I believe hardox/bis 500 needs 1/2 the cutting speed. Whatever happened the finish is rough as guts. The mounting holes are no where near size and the central hole is somehow off center by .5mm even accounting for taper.

In the last pic you can see the amount it's off by. That should be a tight fit.





Drilling them out was a pain!



that's when those super bosch drill bits were discovered. They made mince meat of all 16 holes Smile



Whatev's deal with the rest of the blades problems when i get to them. For now the hub needs to be remade due to the thickness of the new bar changing all the offset. $330 for a 114mm diameter offcut, 330mm long of 7075. It better be good! (it was)



Lil bandsaw did a good job of it surprisingly. Just didn't have enough capacity to get the last 14mm Razz



Starting to machine. The vfd conversion made this so much nicer to do than the last one. And the lack of gummy swarf wrapping around the chuck doubly so. Check out the swarf from just the first operation. Ended up filling 3 huge garbage bags worth for the whole robot XD




Didn't take too many pics of the hub, but essentially the part is the same as last years. Just a bit thinner on the flange and the bore is a bit larger to save some weight.

The pulley was rather quick to make this time having made one before.

Outside is turned to size, 15mm bigger diameter this year for a bit more gearing. Employed my super secret v belt angle for uber grip Smile



How many passes do you think the bore took? A hell of a lot beyond what you can see there as the final passes took forever to get that press fit on the hub just right. Requires a gear puller to slide it off heh.




In the name of not wasting any of the good aluminium, i had to get creative when propping the part up in the bandsaw. Worked well though.



*Tadaaa* The holes in the hub were done in the rotary tablel. 4x m8s and 4x bored for a hardened 8mm dowel pin.

To make the assembly actually fit together, the center bore needed to be drum sanded out with a dremel, the bolt holes drilled to 9mm instead of 8 then the dowel pin holes were done in-situ. Amazingly the whole setup needed very little balancing and is probably the most balanced weapon I've come across. Very happy in the end.



Comparison with the old one. Same diameter and weight but probably not as much inertia. Still - I think you will agree based on the event vids she hits pretty damn hard regardless Very Happy



3x m6 drilled between the interface of the hub and pulley. This stops the pulley lifting off or rotating relative to the hub. The resulting look is also awesome when disassembled.




Lo and behold, everything fits! *phew*



With the weapon in the pulley height needs to be reset on the motors for the new weapon pulley height. Gotta check they still spin nice and concentric -



All the carbon base and top are done plus the weapon which is all the main parts. Went on with repairing the broken front parts of the frame. Originally I had only ran over the front with the tig torch with no filler to reduce any heat affected zone, clearly they needed to be welded fully which is what happened. Not much HAZ anyway as you can see there.



The banebots drives bolt into Decimator through the bottom, and also through the top to brace the top and bottom panels of the robot together making it a kind of monocoque. The last ones were some horribly hacked out 10mm ali bar that were taped to the top of the gearboxes. So shonky. Made some nice single piece 7075 ones from the offcuts this time.

Did anyone say... more mdf jigs Very Happy Took a bit of the 50mm round, and did a two piece jig to scribe the cut lines in. I am so so lazy.




Slitting sawed them to size then popped em in yet another jig to drill the 4 holes. Worked great as always.



Lastly the centers were pocketed out to save weight. There they are sitting atop the drives. Ended up having to make them unique to the left or right as the banebots are actually different heights by about .4mm. Never noticed that before..



Coat of my favourite paint later and its time for the final assembly. Woohoo.



Getting a few small jobs out of the way. I'd planned to copy nick for the power link by soldering a 200A fuse across the power link then gluing it into some UHMW rod which makes the power links quite tall...

Seems everyone was using huge fuses, does no one know these tiny ones exist lol?



Unfortunately i made a bad and the links wouldnt fit in the height I'd allowed. D'oh. Had to use wire instead and put the fuse elsewhere. Anyway i just potted them in with epoxy and microballoons. Theres a slot milled into the UHMW rods for them to rest in for anyone interested in the failed items.




As things go, it was a dumb idea because they were pretty heavy and just soldering a loop of wire around the XT then wrapping a cable tie about it works just as well. Plus it's easier to swap the fuse straight in then throw out a link that took a while to make..

Last part of the weapon was to redo the bottom washer cup. Last time a long hex nut was machined to fit into the cup that the robot rode about on. That was a little bit of a stupid idea as the robot could happily ride on the front of the frame instead and i wanted to use a nyloc to stop the lot coming apart in battle. Thusly the washer was re-machined from 7075 with a larger diameter and bigger bore to fit the 14mm socket in for the nyloc.

Obligatory lightning holes too. The part is way bigger than before but only 7g heavier in the end.




Wiring. Hate. So much. Managed to force myself to just get the damn lot done in one sitting. The whole assembly all comes out attached to the two UHMW modules. Mesh guard is used to stop things becoming abraded and the ring terminal junctions are covered in loom tube. Pretty swish. The fuse holder came out particularly nicely too. The receiver sits on a piece of hdpe that clamps the brushless controller in.





Finished off the paint with some blood spray and that is that!




Whey-hey, not so fast junior. Ended up being 200 grams overweight. TWO. HUNDRED. GRAMS. HOW EVEN Sad

This was about 3 days before my plane left. Leaving me to feel much like this



Not afraid to admit, I full on shit myself thinking that amount of weight loss was not possible. The chopping had to commence asap!

First port of call for weight reduction. Go for the steel. The pins in the disk were needlessly long so those were hacked off.




Next up, this lip is wasted weight. Turned out the weapon needed more clearance so it had to go anyway.



No time to gut the robot to grind it off, so i uhh... No Mum, no idea where the glad bags went >.> <.<



Welded up that part of the chassis to make it a bit stronger then ground that back.



Still not underweight. Gah. Attack the aluminium. Lots of grams locked up in the main pulley. 8x more holes went into the bottom side.




The pins in the main hub don't go all the way through, so was able to put a big counter bore under them.



Stuck another 3x holes in the pulley/hub join. A good idea anyway in case the original 3 stripped out.



Went to town on the drive spacers. Apparently they are now Antweight beaters Razz



Shit! Still a few grams to go. Gutted the electronics and hacked the UHMW down then pocketed them to within an inch of their life. Crudely I may add. Wasn't all bad as they were a pig to get out or in at their original size.



Something like 5g over still and literally nothing left that could be cut out. The wiring loom was already shortened, every bit of steel trimmed, the aluminium and uhmw too. Sooooo.... I pocketed my battery foam Embarassed Laugh if you want but that saved like 15g Laughing



According to my scales he was now underweight. Phew. Was the day before i left by then so i slapped it together and packed everything. As a plan B i ordered a 5s battery from hobbyking that was 100g lighter which would get me out of the shit.

So thusly, the build is done! Many drinks were had pre flight as it was gonna be a long one. (28 hours all up).
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Last edited by Glen on Mon Apr 20, 2015 6:28 am; edited 12 times in total

Post Mon Apr 06, 2015 12:59 am 
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Glen
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THE EVENT

size=18] PRE EVENT [/size]

The Wednesday was available for testing and tech checks at the champs, so wandered over to unpack the shipping crate and get everything set up please meet some strangers Smile

Everything made it unharmed which was a big relief! Slapped the battery in decimator and gave it a test against an old PC, seemed to work well but the weapon motor had gotten a little crunchy in one spot. The robot is really quick too, but very prone to drifting around given the weight over the front and the crap banebots wheels.

Pulling the motor apart revealed the stator was actually delaminating, causing a chunk to rub on the magnets. Swapped to the spare and all was well. That meant decimator had to run at a bit less power as the original motor was rewound to operate at 6s, the spare is a stock wind good for 12s..

Anyway, passed tech check okay though it definitely needed a better weapon locking bar so that's something to be wary of next year. Weight was SO CLOSE!!



With the 6s pack i had to remove two of the top bolts and it was just on the limit. Eek. I'd ordered a 5s pack earlier in the week in case it was overweight, but that didn't make it in time. So the rates on the drives got turned down to 50% to make it more controllable and that was all for the day.

size=18] DAY 1 [/size]

Mercifully the battery arrived at the post office the previous afternoon, So Nick and i hooned 30 miles to Bromsgrove to get it before everything started. Many many thanks for the lift Nick, could not have gotten through the event without that battery.

Having that meant i could be comfortably under the weight limit, and add a little reliability.

First fight! Binky vs Wedgie. Binky has a large vertical spinner and a big scorpion motor behind it. The armour looked thin-ish and the weapon arms are pocketed out aluminium so figured a huge hit would probably bend something.



Wedgie is a co2 flipper of an odd shape. Its body is made from fibreglass or something odd like that, If he didn't flip me out then i figured he'd be easy to knock out.

https://www.youtube.com/watch?v=HoLm2FYSWbc

My plan was to avoid binky and take out wedgie, then come back and deal with it last. A couple of glancing blows on wedgie had parts flying off, while binky seemed to have trouble moving. I had a perfect run directly at it, figuring the bar was spinning in the right direction to throw it out of the arena, so i rammed him and that bent the front end enough to knock it out.

I discovered then that the YEP brushless controller also doesn't like the bar slowing down after a hit and resets. I had to return the throttle to zero for a second or two then it would go again. After some back and forth driving, trying to line each other up i got a decent go of the arm on wedgie which mangled it, KO'ing wedgie and giving me a double knockout win. Awesome!

The front off wedgie, IIRC they were thin titanium -



Damage to binky. Looks like i got a good hit on the bulkhead missing the blade somehow and bent that all up.






Nothing to report on decimator after the fight, just charges his battery and buttoned it up for the next fight. Surprisingly very little battery got used, though that's not surprising given the very undervolted weapon motor.

Next up for me after a decent wait, Flow vs Defector vs Decimator. Flow has a rediculously massive ram! at least 80mm bore and maybe the same in stroke. Videos of it show it has enough power to slam people off the roof. Defector is also a full perssure flipper with big invertible wheels.

Flow also comes wrapped in titanium with a 10mm thick flipper arm and was quite fast. Was worried they might gang up to try take me out early, but as things happened Jarvis didn't get flow running in time and had to forfeit, leaving just defector and i.

https://www.youtube.com/watch?v=OeUi9378H5c

The aim was to avoid him as long as possible to get the bar up to speed, after that there probably wasn't anywhere he could take a hit from the bar given its mostly plastic.

Managed to avoid him long enough to get up to speed once and took a chunk out of the corner, then got him again which managed to remove the entire drive out of one side!



The new bar also makes a nice mess of plastic which i'm happy with.




Gareth managed to get defector back together in no time as well, so all good in the end Smile

size=18] Day 2 [/size]

For the first time since getting there we managed some proper food. [screams]



First fight for me was Wedgie again and minimoth. Wedgies builder was working on it all the previous day to get it back to shape again, and to his credit got it looking brand spankin' new again.

Minimoth was a curious machine. Built by kane aston of behemoth fame, it has 6 wheel drive with HUGE quadcopter out runners. The side pods are super thick UHMW and the plow is titanium.

Really had no plan going into this fight. I hadn't seen mini moth in action and didn't know what capacity wedgie was running at. Just had to make up a plan as i went Smile

https://www.youtube.com/watch?v=EDRm_6uUHSU

Neither robot seemed to want to box rush me, so the blade got to full speed and i went after minimoth. Got a nice hit on the edge of the plow, sending sparks flying, followed by another which nearly pitted minimoth, argh!

After some manoeuvring, Decimator was back to full RPMs and got a solid hit on wedgie then minimoth. Unfortunately that sent Decimator recoiling towards the pit out of control, it then gripped the steel inside and tossed itself out Crying or Very sad Ah well, that is very much a risk with a horizontal spinner in that arena.

That same hit knocked minimoth out leaving wedgie to win by KO. Despite the loss, i did some serious damage to minimoth.






Decimator only needed a charge afterwards. The drive motors were also coming loose as was to be expected with no support. They weren't an issue yet anyway.

Next fight of the day was Hatchet and Valkiri.

Hatchet was a plastic axe robot with a steel wedge, and valkiri was a huge vertical spinner with a big plastic body on it.



The plan... hard to determine. I wanted to avoid valkiri and hope hatchet would go at it then take my time to get a good hit in on them both.

https://www.youtube.com/watch?v=qsiDj_D5nTQ

Valkiri straight away took off after me, i took off to the other side of the arena and got up to speed while hatchet went for the vertical spinner. There was a good opportunity as valkiri recoiled, so i went straight for the side in a big charge, hoping i could take off his wheel.

The impact left the corner of valkiri mangled, but because the body was so huge everything was still working.

He turned around while i was getting back to speed, i had another go at his wheels but he gyro'd over on top of the robot, taking a decent chunk out of the bisalloy top. What i'd failed to notice like a n00b is i hit the pit button Embarassed Backing up to try get some speed up on the weapon resulted in me basically driving straight in the pit and KOing myself for the 2nd time. SO SHAMEFUL.

After that hatchet got a great ram in on valkiri, making it hit the wall, hurling itself out in the process!

Was super happy for Sam that drove hatchet as he was proper nervous and expecting to come out in a bin bag. He seemed slightly pleased he came out instead with a double KO Razz

Valkiri damage. Good old air armour.-




That was it for the qualifying rounds, only the highest scoring 10 robots would make it through. Decimator was 12th or 11th from recollection, dropping out of the main comp. Ah well, was happy with the path of destruction he left behind.

There was still two comps left on the Saturday and Sunday. One is the gladiator tournament, basically a free for all with no time limit till no one is running. Didn't think i would do too well in that Razz

Then there is the annihilator that we all know, so i entered that along with Sam Smiths NST, Flow, Defector and a titanium wedge made by the little nipper guys called cannon fodder.

https://www.youtube.com/watch?v=p8x1bm-vNb4

Not much point commentating a 5 way fight! So watch the vid Smile But i smacked flow a few times, flipping him over and KO'ing it and ending the fight. Decimator though seemed to have problems. One side of the drive was intermittent and the weapon also seemed to have trouble spinning up.

damage to flow -





The drive looked to be a problem with the TZ85, so i ripped that out and found the inductor hanging off for the BEC. Annoyingly i disabled the BEC on the other controllers leaving only this one active, that being the convention back in the day, meaning i had to replace this one.



Was about 5 minutes too late in getting it back together, flunking out of the annihilator as well. Dang!

Putting it back in for a test the weapon wouldn't start without a kick. Didn't have the time to trouble shoot it, so i threw it in for a grudge with conker and hardwired.

https://www.youtube.com/watch?v=YJTXl9ZiwjI

Couldn't get it to spin still... Conker hurled itself out so we restarted the fight.

Which then resulted in the brushless controller detonating Laughing That is a mighty fine fire if i do say so myself.

https://www.youtube.com/watch?v=aZ2FcDpeCB0

The cause was the insulation broke down on the scorpion weapon motor, shorting out a phase. The constant attempts at getting it going caused it to kablammo!

And with that the event was done for me Smile Had an amazing time, met some amazing people and by the time i was back at the hotel was already thinking of what to do for next year.

Hope you enjoyed the write up Smile
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Last edited by Glen on Thu Jun 18, 2015 1:02 am; edited 3 times in total

Post Mon Apr 06, 2015 12:59 am 
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Glen
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THE POST MORTEM

Right! Well. Lil deci is still but a baby of a robot, using many techniques not seen on (many) feathers like the all carbon structure the internals sit on plus the can pulley on the motor, and an asymmetrical bar.

Considering this, and that really this was its first event* Decimator worked well overall. Of course there's much to develop and change and hopefully a lot of life left in this machine, even though there's many ideas floating around for a much more heavily upgraded version i may make next year.

Here's my thoughts on what worked and what didn't:

YAY

- Asymmetrical one toothed bar

That weapon owned, basically haha. Unlike demon that required the weapon be rammed into someone to get a good bite, nearly everything that weapon touched seemed to get hit in a big way. The engagement of it even at top speed is fantastic.

Despite on paper having much less KE than the old disk, it hit's adequately hard. Very happy with it Though the wear on the teeth was a bit harsh. I reckon 2 big full combat events per bar will see them worn out. Given the cost that is okay.

- Legit carbon fibre.

Was sure they would crack, but it was never to be. The stuff is super stiff and seemingly tough (touch wood). The cost is crazy though so the next version won't be using it. Considering i had backed myself into a design corner so to speak with this version where there was no more weight points to use up, the carbon does the job perfectly.

- The proportions in general

Seeing how horizontal bars tend to throw themselves around, decimator seems very stable with its wide wheelbase and nubby, short bar. It really only had one moment hitting minimoth where it tilted up on its side, but was just unlucky that happened right over the pit! Drives nicely too, just let down by zero traction which i will fix next time.

Any future variants will probably share the same proportions as this current version.

- Removable links

Heathen! I hear you say. I know... But, they worked great, they cost $0 and can be made almost universal in size and shape to fit. That and there is a slight easing of the mind knowing the link can quickly be yanked it out, especially whilst testing.

Will definitely just use them in all other robots if i can. Decimator has to go up in size i fear though as it melted all 3 xt60 links!

NAY

- Banebots wheels

No! Awful! Bilge! Robot poison! They are a total waste of money. Zero traction means the robot would just drift around the arena. let go of the transmitter while moving and the robot would drift about half a meter into the wall with the wheels stopped.

Not to mention they wore down to the core after 3 fights. Utter shyte.. Colsons or custom wheels from now on.

- R620 OrangeRX reciever.

I have never been so angry at a radio before D: ! Ever since i got the thing it refuses to link to the tx in any consistent manner. It took about 5 goes of turning the robot on then off in one round before it would link up, was so close to just forfeiting..

I've purchased a 615 reciever to try out, if that's the same ill bin the orangerx gear and go spektrum once more. Hoping it works as i do like the tx quite a bit.

- Electronics mounting + wiring

Once more, what looks like a big chunk of room in cad, does not translate to reality. There was simply not enough room to wire this robot with servicability in mind, although somehow, the setup much better than the very first arrangement.

Was such a pain to get the ESCs out that i missed the 2nd round of the annihilator, not that it would have mattered as things panned out.

Next version will have everything on a shock mounted plate with plugs that can lift out. Rapidly being able to swap everything is clearly a huge advantage. Next year i will probably make 2x of these so if there's any issue i can have a whole setup ready to go.

MEH

- Pulley on the motor can

Well it ran through a bunch of fights, so i can't say it didn't work. But it was clearly twisting the can of the motor enough to grind on the stator. It happened quite bad on my first motor such that it wasn't able to be used.

That was annoying as it was the one that was rewound to have full power on 6s instead of the 12s the HK4035 motors normally run at, so the fights you saw were all at a very reduced power.

- YEP 150 controller.

Once again, can't say it didn't work, cause it did. And the explosion was no fault of it's own. The motor shorting out was the issue. Given that it lasted as long as it did driving a shorted out motor, they seem very robust hardware wise.

Although Haz had an issue with the controller going back to its default settings. I didn't experience it but something to keep an eye out for.. Will probably use these again Smile

So anyway, that's a condensed run down of things. Future improvements will be documented later in the thread. Cheers for reading and hope you enjoyed the journey!

*one 10 second fight and zero testing at the nights is hardly any kind of event Razz
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http://www.youtube.com/user/HyzerGlen - Videoooozzz


Last edited by Glen on Thu Jul 16, 2015 10:55 pm; edited 11 times in total

Post Mon Apr 06, 2015 12:59 am 
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haz



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Learn me how to horizontal plz thx.

Thats a beautiful robot there mate.
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Post Mon Apr 06, 2015 3:10 am 
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Jaemus
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So whars that 4 page build report then? lol
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Post Wed Apr 08, 2015 8:58 am 
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Glen
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Ahoy, hoy

Did the build report finally Smile Totally ravaged with jet lag, going to sleep at a normal Australian time is doing nothing so trying the old stay awake for 30 hours trick Razz Lots of time to type!

Hopefully it's not too scatter brained. Will do the last two tonight.

Enjoy.
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Last edited by Glen on Mon Apr 20, 2015 3:12 pm; edited 1 time in total

Post Mon Apr 20, 2015 6:42 am 
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miles&Jules
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Awesome write up there dude-Was the jet lag worse arriving in uk or worse on the return?
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Post Mon Apr 20, 2015 3:03 pm 
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Glen
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The return is utterly brutal as you go back against the day/night cycle. Days and nights are really short on the return. I've slept about 30 hours over the weekend and still can't get back into sync. Staying up all last night and today to try get back to normality haha.

The event was amazing but those flights are just punishing. Specially alone. Will have to be a pre-requisite that someone comes along next year to make it tolerable ;P

Cheers for the compliments too.
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Post Mon Apr 20, 2015 3:12 pm 
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miles&Jules
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Well i guess its better that the jet lag was worse at this end …otherwise your bot driving may have suffered.

When we went to the USA we had terrible jet lag when we arrived there…did some serious sleep ins on our first few days of holiday.
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Post Mon Apr 20, 2015 7:32 pm 
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