Heavy Weight Spinners 2011 !!

**typhoon_driver** · 8th July 2010, 14:36

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** · 8th July 2010, 16:52

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** · 8th July 2010, 18:04

This might be useful in calc the moi etc.

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

**grant_ploughbot** · 8th July 2010, 18:29

Originally Posted by rallikas

Why not a wood roof?

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

**rob** · 8th July 2010, 19:35

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.

**team_orr** · 11th July 2010, 02:35

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** · 11th July 2010, 09:07

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** · 11th July 2010, 12:03

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** · 11th July 2010, 13:55

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