Heavy Weight Spinners 2011 !!

[gravity]

Re: Heavy Weight Spinners 2011 !!

Can I weld a disk to gravity and try it out at RIAT ?

[Marien]

Re: Heavy Weight Spinners 2011 !!

I think some people might be getting confused on jonnos concept

Maybe a little bit about where the wood should go :-)
But I am serious about the HDPE disc.

[psycho_fling]

Re: Heavy Weight Spinners 2011 !!

well the whole point of the wood was for the destruction element

[craig_colliass]

Re: Heavy Weight Spinners 2011 !!

Just a few thoughts on the idea

Arena
With regards to bits coming through the roof of the arena my first thought would be to leave the netting as usual and then fit over that 1 of 2 parachutes or similar secured to the sides only and left to rest in folds on top.
As anything makes its way out of the arena the light but strong material from a parachute would wrap around it and then slow its speed down till it had no energy to penetrate the parachute, the trick is in letting it fold onto the old roof material.

Spinner
The main thing to watch is tip speed this will more or less dictate how fast any bit will be flying off the robot. Also I would advise the disc is made with the teeth as one piece. This will eliminate any problems with hard tips breaking off when bolts shear. Case hardened mild steel would be good for this application.

Sacrificial Armour
HDPE would be very good for this as long as it was held on with a hopeless fixing, like Velcro as this would mean you could pick up the same armour parts after the fight and just stick them back on. A few Pyrotechnics and everyone is happy and no repair costs to worry about.

Hope this helps


Craig

[john_frizell]

Re: Heavy Weight Spinners 2011 !!

Sort out the rules and let me know. I'll build a spinner.

[typhoon_driver]

Re: Heavy Weight Spinners 2011 !!

An interesting concept. I'd recommend single piece metal discs, other materials would likely shatter, split or be too unpredictable. You're main problem is limiting the kinetic energy of the weapons and if you go back to basic equations you are therefore either limiting the moment of inertia or the rotational velocity. Rotational velocity is relatively easy to limit however MOI is a bit more tricky.

I'd set yourself a limit of say 500J or 1000J of kinetic energy then work backwords from the worst case disc design to determine the max dimensions and weight of said disc.

As mentioned earlier this may be safer with middleweight sized machines. Audience wouldn't be able to tell the difference and the forces involved are likely to be smaller.

You're roof is gonna be the problem area but as it doesn't have to be see-through would it be possible to throw a few mm of a cheap impact resistant plastic such as HDPE of the top of your current netting?

Velcro armour? Good idea!

I'm watching with interest as I wouldn't mind building a bigger spinner at some point and knowing me, I'll try and push it right to the limits for fun

[rallikas]

Re: Heavy Weight Spinners 2011 !!

You're roof is gonna be the problem area but as it doesn't have to be see-through would it be possible to throw a few mm of a cheap impact resistant plastic such as HDPE of the top of your current netting?

Why not a wood roof?

[woody]

Re: Heavy Weight Spinners 2011 !!

This might be useful in calc the moi etc.

http://www.members.toast.net/joerger/root/spinner.xls

[grant_ploughbot]

Re: Heavy Weight Spinners 2011 !!

Why not a wood roof?

Because you need atleast 18mm of good quality plywood to be as good 3mm polycarbonate for projectile impacts.

[rob]

Re: Heavy Weight Spinners 2011 !!

how fast did hypno-disc's weapon spin 500 - 750 rpm when it first appeared on tv? would that be too fast for the arena?
with light armour on the other bot = plenty of dammage and from what i can remember the pieces never flew that far. http://www.youtube.com/watch?v=w04BgclPmY8

[team_orr]

Re: Heavy Weight Spinners 2011 !!

this sounds like a cool idea jonno, could be what we need to move forward, craigs idea about the parachute is brilliant, when i first read this the first thing that rang alarm bells was the net roofing, but if we have that resolved obviously there will be other safety aspects we will have to fix/improve, and it will be interesting to see if the fra will let this happen,

as far as limiting the spinner goes, apart from being horizontal, will there be any rpm/motor/voltage restrictions? i have a few spare motors lying around (litton, bosch etc) that i could use...i also have a spare disk so this could be a plausible summer progect

the idea of sacraficial armor is good too, hdpe or wood, loosly held on with velcro or a few bolts, the crowd would love it

also, would featherweight spinners be allowed? it would be good to get them out more often

jack

[robotwars]

Re: Heavy Weight Spinners 2011 !!

Some good comments and suggestions...... I think people get the idea, that its not about FULL COMBAT, its about entertainment and destruction.

Hoping to have some rules sorted after Riat so a few can have a nice summer project if they so wish ready for trials at portsmouth !!!

I did all the spinner / energy calcs / stress analysis at uni for my end project so I know what goes on !

John

[dragonmaster_1]

Re: Heavy Weight Spinners 2011 !!

Well i think i will take the 750s out of Carnage and the 400s out of Dragonfly and swap them around. Put the 400s on the disc and alter the pullys and run them on 12v. try for about 300 rpm.

[widow_twanky]

Re: Heavy Weight Spinners 2011 !!

I am temted to do a similar thing with SMIDSY.

One of the problems I have with velcro for holding on armour is that you can't control which direction it will fly off. That said if it's a large piece designed to fly off it's unlikely to penetrate the roof netting as much as a spike or something similar.

Anyway, my thoughts on SMIDSY.

As said above run it on 12volts possibly running 12v Bosch 400's (if anyone has two spare!!). Stick a skin of 3mm ali on the outside set off the body with some rubber fixings so things can get underneath and rip it. The put a layer of 1mm ti on top so we can have some nice sparks and stuff, could get expensive if it needs replacing too regularly but we shall see.

Andy

[dragonmaster_1]

Re: Heavy Weight Spinners 2011 !!

Think i will wait till Jonno posts some rules as Carnages disk is rather large