Robot Stats

Team name: Overkill

Robot name : Slash

Team location:Sydney NSW

Robot weight(Class): Beetle weight

Type of Robot: Undercutter

Drive system :2x B-series motors from the RMP

Type/size of wheels: Rubber model plane wheels

Weapon drive system : AXI brushless outrunner motor (over-volted)

Speed/motor control : Scorpion ESC

Power: LiPoly 14.4V, 1.8AH Polyquest pack, capable of 15C or more discharge rate

Armour : Optional spring steel sheet over UMHW body panels (depends on spare weight)

Length Width Height : 148 x 148 x 50mm without the weapon disk

Type of radio controller : 3 ch FM

Radio frequency: 75MHz

General comments : The plastic and composite body parts, along with the high Power to weight ratio of the weapon components means that this bot has excellent offensive power

Unusual characteristics: Large titanium weapon disk, which is larger than the body @ 180mm diameter
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

Now that the POP is taking shape, its time to give my beetle weight its own report and a new name. In keeping with the Team Overkill naming theme. I’m calling this one ‘Slash’. Here is the POP so far:



The AXI motor is simply insane! Andrew and I wired it up last week and at 14.4V it spun at probably 15,000 RPM and produces an evil howling sound – I had expected it to be fairly quiet. With a 4:1 belt reduction, the weapon will have a quick spin up and the proportional speed control from the Jeti controller will keep the current draw down so that the LiPo pack doesn’t overheat. How this tiny motor produces over 150W of power without melting is beyond me!



The body had to be enlarged to fit the Jeti controller, so the sloped front design had to go. I will use 3mm Garolite for the top & bottom plates for the moment and change the bottom plate to 3mm CF when my sheet eventually arrives. The vertical body panels are all 10mm UMHW and everything is held together with 6g sheet metal screws. That might sound dodgy, but my experience is that this construction is very strong and dependable.

I am still waiting on the LiPo packs, drive motors, ESC, large pulley and weapon axle, so I can’t get much more done for another week or two
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

woah doctor, that thing looks badass.

must build crusher
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www.demon50s.com - Minimoto parts
http://www.youtube.com/user/HyzerGlen - Videoooozzz

Sweet... um nick, two things, one: when are the scorpion's arriving?
two: Can i still buy that Ti offcut from you? The hole placement isnt completly important... but next event i can give you a rough idea (one on each corner and four more along each side, i'll draw it)
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I just got a message from Robot Power today, saying that the contollers were delayed and would ship on Monday rather than mid last week. It should take around 14 days from tomorrow to get here. The Ti ofcuts are looking a bit slim, I will bring a diagram along next Saturday and we will see if anything suits.
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

Slash is making good progress and the parts are continuing to arrive - I recieved this Polyquest LiPo pack yesterday:




Its one of the new 15C to 20C discharge rate models and saves substantial weight compared to a 10C pack.

I finished most of the UHMW parts last night, just the big bearing block at the front and a small baulkhead to cushion the Jeti brushless controller. The photo below shows the chassis sitting on a CAD drawing to show how the weapon disk will look.





All the remaining parts are coming from the RMP and are up to two months late, so I am going to ring Jim tonight and ask if I can get anything that's in stock shipped ASAP.
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

Don't bother rushing... it'll be quite a while till there's any other beetle to compete against!
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you should have called that thing the volvo, it scores a perfect 10 on the box-o-meter

love the way you milled the foam into the battery bay, and is that the final shape of the bot? just a box with the undercutter out the front? and where do the drives fit in anyway
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www.demon50s.com - Minimoto parts
http://www.youtube.com/user/HyzerGlen - Videoooozzz

I was going to put a roll bar on for self-righting, guess that would be too much volvo-ness! I started out wit hmore of a pounted front, but the internal parts needed more room so the box made a comeback.

The drive motors (RMP B16 motors) go underneath at the back; you can just see the outside of a wheel on the CAD, in the lower left corner. The wheels should fit completely under the bot and I have some .02" spring steel sheet to make skirts around the back edges of the bot.

It looks like the weapon disk will be ready in 7 to 10 days - can't wait!
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

Hey nick... where did you get your battery pack from?
Could you give me some idea on what shape and size your Ti scraps are?
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The LiPoly calls came from www.purehobby.com in the USA - they were very easy to deal with, delivery was prompt and the prices were reasonable. I was going to use Hill Top Batteries (the Battlepack people) but for some bizarre reason, they don't ship LiPo cell internationally. There are plenty of RC shops selling Lipo cells, but not so many selling the high discharge rate Polyquest variety.

The Ti cutting has hit a few snags; Laser Wizard, the cutting place, can't read my CAD drawings and are not bothering to convert them as they did in he past. I have to redraw everything from scratch in a new CAD program (after I learn how to drive the software, which is going rather slowly )

The offcuts are (probably):

4 x 350 x 50mm ( I may use some of this up on Jolt as armour against plans B and F )

4 x 345 x 80mm

4.6 x 158 x 20mm

4.6 x 135 x 20mm - both these pieces would be good for beetle/ant weapons
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

Progress on Slash has slowed down while I wait for parts to arrive from the RMP. I phoned them a few nights ago and only got a message telling me to send an email about my order status - no joy there!

I did get some new raw materials today - a sheet of 3mm CF from the local Southern Composites place and a sheet of 0.5mm spring steel, which will make excellent armour for Slash to protect the wheels and motors.

A 300mm square sheet of Garolite and a sheet of CF gives me enough material for 4 chassis so I will eventually be making a small army of Slashes - there's nothing like having plenty of spare parts!
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

Why did you choose spring steel?
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So even the rain that falls isn't actually going to fill our dams and our river systems

Depending on how much it costs, i'd probably take both the middle ones... They both would be very usefull lol
How did you find southern composites?
When you finalize the cad let me know... i've got a few places i'd like holes cut. Cheers!
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Quite a few reasons: Curiosity , Lower cost than titanium, High surface hardness (ie spinners can't get a "bit" on it, and its layered over UMHW, so I am hoping the springyness and the plastic will distribute and soften impacts. Finally, its easier to work with than titanium.

Several ant and Beetle builders in the states have used this technique successfully so I figured that for less money than titanium, it was worth checking out. The steel is so thin that the armour only weighs an estimated 70 grams.
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion