Tornado Mer like robot, HELP.

[AbundantToast]

Hi I am thinking of building a robot like Tornado Mer, but I have no clue how to make such a smooth, circular body/chassy like Tornado Mer. Any Help how to make this?

[Metal Demons]

Re: Tornado Mer like robot, HELP.

Tornado mer is not a good design, don't bother... it will take you some tricky engineering to get the blade lower than quite a few of the wedge bots out there, and that isn't done then your robot just won't be able to do anything. The best bet is to build something like Hazard, basically a wedge robot with an overhead bar... the wedge helps you get anything lower than the bar up into it.

If you still want to build it, heat bend some UHMW into a ring around a former and weld the ends together... it welds pretty nicely with an appropriate plastic welding setup and will be a lot cheaper than milling the ring out of a plate.

If you're doing something like the original design you wanted, the best design would be a fbs/shell spinner... to build the shell there are a few approaches: you can get it rolled out of sheet and welded before balancing, or just mill the whole thing. The sheet approach is most economic but both will be expensive, milling very so unless you have a mate with a bridgeport or something!

Also driving an overhung blade is tricky, big bearings and a hefty mount will be required which will take more machine work...the only off the shelf solution is to buy a right angle gearbox for a magmotor from team whyachi robotics (google them) and use a magmotor to spin it - the two combined will probably set you back 700 quid and that's without a blade. Failing that you can machine your own bevel gearbox (use hardened spiral bevel gears and hopefully some kind of clutch, either where the blade mounts or the input or both) or drive it with another approach - perhaps push fitting a pulley over the can of a brushless and belt driving it from that?

Either way... a spinner of that kind is quite an undertaking to build in any way that will give you something effective.

[typhoon_driver]

Re: Tornado Mer like robot, HELP.

I'd suggest a robot design similar to tombstone would be easier to build http://www.saidin.com/robot/bot_pics/Tombstone.jpg

[AbundantToast]

Re: Tornado Mer like robot, HELP.

Thanks guys, and for your replys. (Oooo rhyme ;D) Yeah, that ticked to me last night about wedges getting under before you said that so Ill probally build something like hazzard. But my only futher questions are What sort of motor would be needed to spin it what I could fit into a wedge? And the FBS sounds a good idea but it seems to complicated for me (Balancing it and all) And I thought they could only spin to 500 rpm, which sounds to me that it would be a total waste of time and not that effective. I decided to go for the bar spinner after witnessing Tornado met my self when I was on holiday in the states and i've been inspired by it. So I figured i'd try make it as low and compact as possible that should give the best bet to getting my wedge under other wedges . I think some skirts are in order to stop those darn flippers .

Thankyou
-Toast

[Metal Demons]

Re: Tornado Mer like robot, HELP.

500 rpm limit is only for spinning on the spot in non-spinner events... in a spinner event you can go to whatever speed you can!

As for driving it, best bet would be one of two ways - a right angled gearbox or a belt drive off a pancake motor, preferably a brushless outrunner with a pulley press fit onto the can. You'd be looking at either a big brushless (which I'd stay away from as the currently available controllers aren't terribly good and blow up an awful lot, talk to Dave (builder of 360) about how many he's been through) or something like a 28-150 magmotor in order to build a really creditable spinner, though other solutions have been done and worked.

Berzerker (my spinning bar undercutter, as yet unfinished due to controller problems and being pretty occupied atm... I was hoping to make it to the UK champs this year but it didn't happen) will be running off two 4.2kw brushless motors with a fairly unconventional right-angled belt drive, but that's a pretty extreme example of overkill in weapon power... something more reasonable will be easier to build without a ton and a half of machining.

One of my previous designs was an overhead bar spinner actually, but I ran into problems getting it low enough... fitting the right-angled drive (bevel gears in this case) and the 2 large bearings required to support the weapon shaft (which is overhung, remember, so won't NEARLY be as strong as a setup with the weapon supported on both sides) in will be tricky. Running the weapon on a heavy dead shaft mounted to the chassis is probably the best bet as it lets you mount a bearing above and below the blade while still keeping the height down, and then you can drive the bar from a belt drive or a gear... I'd choose a belt to avoid massive deceleration shocks to the motor (which will have a fair bit of inertia in the rotor and therefore you run the risk of damaging a shaft or spinning the rotor on the shaft), but a straight up gear drive has been done (in 360 for instance) and has worked well so far. The other advantage of belts is that if anything DOES get tweaked (i.e. by a huge spinner hit) then they stand a much better change of continuing to work unlike gears, which will bind up with only a very little structural deformation.

[PJ-27]

Re: Tornado Mer like robot, HELP.

So you can enter spinners in norml events? They just have to be under 500rpm? How do you measure that?

[AbundantToast]

Re: Tornado Mer like robot, HELP.

Yeah, Ill speak to dave about his motors Thanks