Conundrum Mk1r2 - Team Robotic Death

[psycho_fling]

hi

i not sure a cardboard base would be suitable in any robot-it's hard to sense sarcasm on a forum post so sorry if you meant it as a funny comment and i'm missing it

i think the 2mm base has to metal nothing else- definitely not cardboard

speed 900's with some good gearboxes on can cope fine with high voltages

[RogueTwoRobots]

i not sure a cardboard base would be suitable in any robot-it's hard to sense sarcasm on a forum post so sorry if you meant it as a funny comment and i'm missing it

Yeah I think Chris exhibited the classic signs of sarcasm in his post

Imagine a brushless drum fw, the amount of shocks going through the chassis and then picture a 2mm cardboard base on that. The words epic and fail would spring to mind in that case :P

To be fair, we didn't actually say what the material for the base was, so yeah its a 2mm minimum thickness metal baseplate

[Mouldy]

I would of thought it was painfully obvious but then again i suppose things should be made idiot proof.

cardboard + lipo fire = bad idea.

[robotic_ants]

Well if I could not use cardboard I was going to think about asbestos board about 5mm thick.. but since you say it's got to be metal then it'll be around 4mm steel/ali/hardox or similar.

Asbestos board + lipo fire = really bad idea! :twisted:

On Jamie's point the chassis is the main structural element, the way it's being designed the top and bottom plates won't provide any support or have anything mounted to them. Just there purely to stop people poking my expensive bits with an axe. Should be a long way away from epic fail.

As for drive motors I think the Speed 900 is out of the question because of shear weight alone although it should run 40v. I'm looking at a Thunder Power 8S pack so i'll be running around 29.6v unless I use a 24v motor and set the controller trims, think i've heard of people doing this before. How well does it work?

[typhoon_driver]

Setting travel limits on the transmitter works well. Did it on hornet recently. I was using an 8 cell pack of A123s but my drills were only of the 12v mark or thereabouts so I ran them at 50% and they handled it fine.

[robotic_ants]

With A123's having a limited current burst i'm looking at LiPo's which can provide +200A, but what is the verdict on them and are they worth buying because I know some US competitions have started to pull them out of there larger weight classes like the 30lb's. Mainly due to venue issues like fire and large plumes of smoke which would set of a venues alarms meaning an evacuation of the building and canceling a show.

[robotic_ants]

Quick idea of the rough spec so far..

• - 4kg Drum (we'll see)
  - Around 5hp brushless weapon motor
  - Bosch 35w's for the drive motors, rate limited
  - 3800mAh 8S 29.6V LiPo (see post above)
  - 200A Brushless ESC
  - Milled Ali & Nylon chassis

..think that's about it.

[Mouldy]

What brushless esc you going for? and what gear ratio from what motor?

[robotic_ants]

The motor is only a low 170Kv so with 8S it's only going to be running 5000rpm so i'll leave it at that I think. But going back to the battery issue I might go for a smaller controller as alot of these brushless motors never really reach there peak power unless you spend £££'s on a big brand like Plettenberg or Neu. The one i'm waiting for is rated 5500w but it will realistically reach 4000w if i'm lucky.

[Mouldy]

what esc and voltage?

Id suggest running the motor below its rated voltage..

I ran my old scropion 6s motors on 6s and 2 of the 3 phase wires melted themselfs

Id suggest getting an esc rated a fair bit over what you'd expect to pull.