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Arena Standards
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dyrodium
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Joined: 24 Aug 2004
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... Blast matting. It's actualy designed to stop massive chunks of material moving at great velocity... Stitch some of that up along the roof, nothin's getting through that! Laughing
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Post Wed Jan 24, 2007 10:10 am 
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Totaly_Recycled
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Joined: 15 Jun 2004
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if shade cloth is used it should be pulled down over the sides and secured so it seals over the top of the walls thats how i do it here

Post Wed Jan 24, 2007 10:19 am 
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Knightrous
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Blast matting weights a tonne! Shocked You'd need a structure and a half to hold it up there...
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Post Wed Jan 24, 2007 11:15 am 
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maddox



Joined: 21 Dec 2006
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Independent of the FRA we did some testing.

UHMW PE of 5 mm thick in a flexible mount can
Stops light crossbow quarrels without any serious implications.

Stops an bodkin point war arrow fired with a 30 lbp competion compount bow, damage , negliable

Stops repeated 5 kg sledgehammer blows , but this damages it really. But no pieces came off or the hamerhead penetrating.

The only thing that can get trough in a potential dangerous way is a repeated cutting on the same spot. Like a dedicated spinner or disk saw attack. Anglegrinders melt themselfs in it.

Advantages of UHMW PE compared to Polycarb are
Cheaper
Lighter
Easer to work with
Better UV resistance

Disadvantages.
Gets uglier faster- it's softer to scratch
Not see trough
Needs a good trussing to support it.

Post Wed Jan 24, 2007 1:12 pm 
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Rotwang
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Joined: 15 Jun 2004
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Location: Vic


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Quote

"Grant Cooper Advanced RoboteerUsername: Grant_ploughbotPost Number: 539Registered: 03-2004 Posted on Sunday, January 21, 2007 - 9:21 pm:
James - I did not attend the meeting, but to shed some light on why these guidlines for running spinners has been changed I'll explain. We did some testing....(seperate testing was also done by the FRA) At 100mph - with a 250g projectile of steel, 1" daimetre. This went clean through 12mm plywood, infact it didnt just go through, it smashed through even when sideways!! It was just about stopped by 18mm plywood, but it did penetrate the other side. All the other materials except for polycarb including the very tough lorry curtains, even two layers with stanless steel meshing didnt slow the projectile down at very low speeds! Im sure, even you dont agree with the new guidlines that there must be something done to stop the possibility of things escaping from an arena this easily - to be honest i was extreamly shocked by how badly any materials stood up to impacts. If you run spinners in an arena not to these specifications, then you run the risk of serious injury and insurance will be invalid."



Just scaned through the Pomie thread http://www.fightingrobots.co.uk/forum.htm

The Fighting Robot Association Forum » FRA General Chatter » FRA urgent announcement

This seemed relevant, we have been thinking about the roof situation and having been informed of possible problems something will need to be done to improve it.
By that I mean test or strengthen roof not mandate tethers. Smile
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Post Wed Jan 24, 2007 5:43 pm 
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jamesb



Joined: 05 Feb 2007
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Location: wales uk


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I would suggest you also look at the RFL forum for information on this subject. The treads you should look at are "arena screen material" and "how to build an arena"

For the record, it seems that no real or reliable testing has been done in the UK so I'd ignore the info on the FRA forum.
In fact, the only testing ever done on the subject in the UK that can be relied on is the original Robot Wars ballistics testing conducted on their arena. I have commissioned an indepedant materials lab to give me real world results to follow this up, but I'm not sure on the timescale for this.
The "testing" refered to on the FRA forum is either ficticious or is hugely flawed, so do not rush to spend more money than neccessary.

Just adding my opinion to the discussion, hope it saves you guys from reacting to situations that don't actually exist for featherweights. Most of the problems are related to heavyweights throwing bits of their weapons out of the arena. Smile

Post Wed Feb 07, 2007 12:03 am 
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Daniel
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Joined: 30 Aug 2005
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The other problem I see with all the talk on the FRA and RFL forums is that they always seem to say things along the line of "spinning weapons can have a tip speed of 300mph, therefore we have to have polycarb that could with stand a broken tooth traveling at 300mph". But this statment doesn't make sense. Energy is needed to remove the tooth, break the bar, remove armor or what ever it is that is happening, and that energy has to come from the weapon. If energy is removed from the weapon then it has to lose speed. So the bits that may fly around the arena are never traveling as fast as they are claimed to be. I know we should alway presume the worst will happen, but isn't that what safety factors are for? I'd just like to see a bit more thought put into these claims.

And doesn't the most amount of damage to polycarb screens always come from direct weapon strikes? Shouldn't they be the basis of tests?

Or we could make a standard test that an arena has to survive rather then arena standards. Such as the arena wall must receive no damage from an object weighing 2.5% of the maximum weight class for the arena, traveling x amount of speed. For emaple a 340g object being shot at 250km/h at a feather weight arena. Then we build a chicken gun and shoot at walls. Very Happy

Post Wed Feb 07, 2007 8:19 am 
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Valen
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I can see why one would assume that a weapon tooth could come off at full tip speed, imagine jolt sheering its bolts at full speed. The tooth would leave the bar at basically full speed.
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Post Wed Feb 07, 2007 8:56 am 
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jamesb



Joined: 05 Feb 2007
Posts: 3
Location: wales uk


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you are giving far too much credit Daniel, the guys here still don't realize that there are different types of polycarb for example. Try hitting an equal size and thickness of PalUV test sample and a Lexan Marguard sample and see just how "equal" polycarb is.
Serious, a large pinch of salt is needed.
Believe it or not, poeople here will still swear blind that 10mm of polycarb is bullett proof... regardless of brand UV exposure, mounting method or the gun size.... mad!
For another example, we still assume a motor of 1500rpm gets a 2kg bar to 1500rpm or more.
No such thing as losses, friction, or physics in the UK.
Assume everyone is stupid until they prove otherwise. (of course, I am not saying everyone in the UK is like this, but there are some very convincing "experts" who are basically kids talking recycled crap, knowingly or not, and grown up versions of the same thing)

Post Wed Feb 07, 2007 10:01 am 
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DumHed
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that's pretty much the same anywhere I think.

In the car world there are still countless people going on about how power doesn't matter, only torque!
Never mind that torque is a static measurement, and no amount of torque will ever accelerate a car without some rpm (and the fact that power is torque with revs!)
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Post Wed Feb 07, 2007 10:16 am 
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Spockie-Tech
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Its always the case. People are much happier to recite something that sounds good rather than do the work to find out for themselves. its all about *sounding right* that matters to those concerned with image.

The "Bulletproof" term is meaningless as well, since bullets range from BB's to 44 magnums, and flying bits from robots probably vary just as much in weight and energy. The only person I know of who built an arena and actually tested this was Fuzzy - Theres some details about halfway down this page
http://lazytoad.com/rc/arena.html



Personally I assume that 90% of any information that comes out of a beaureacratically organised group is crap. "Cover your ass" and "How can I tweak this so it makes me look good" are the dominant success rules in any beauracracy, Truth or Facts dont even get a look in until those two are satisfied.

If you want the least distorted information, listen to the small scraps that those who are in favour of an issue have to say against it, and what those are against have to say in favour of it. That is the most likely to be the truth - or at least facts that cant be conveniently dismissed.

or in shorter terminology. Where one stands on any issue depends on where you sit. Wink
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Post Wed Feb 07, 2007 12:43 pm 
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Nick
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Joined: 16 Jun 2004
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@ Jake: I took an RPM reading, did the math and worked out that the tip speed was around 98 KPH. The teeth weigh 320 grams so its easy to work out the theoretical maximum energy.

Of course, the teeth never just come off by themselves and its likely that much of the energy is dissipated in the floor / opponent / wall, like Danial said. I like the chicken gun concept Twisted Evil, but how will we measure and control the projectile velocity?

One of the other dumb things that are being sid on the forums OS is that arenas can be built to 'standards' which are fairly loosly defined and then they will be safe. Unless the standard is incredibly tightly defined and adhered to, it's pretty useless - environmental testing is the only way to go. Build your arena however you please, test it with the chicken gun (or whatever) and then you can say it meets some standard. Ideally, you would up the energy until there was a failure and then you could calculate what safety margin there was.
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Post Wed Feb 07, 2007 1:26 pm 
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Knightrous
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I think a "Pitching Machine" would be better then a Chicken Cannon Cool We could fire random objects with variable speeds...

Clicky Clicky Laughing
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Post Wed Feb 07, 2007 1:33 pm 
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kkeerroo
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Joined: 17 Jun 2004
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I have been through the RFL arena "standards" and I beleive that they make sense. For those who haven't seen them:

* RFL arena nomenclature for describing arenas: formal rating of arenas requires testing and inspection currently beyond the resources of the RFL. The arena ratings are intended to provide a consistent means for EOs to describe their arenas, based on their knowledge and experience.

o D: No protection (no robots that can send stuff flying allowed, and observers and drivers could get hit by a robot) example: parking lot fights]
o C: Little Protection (curb, but no polycarbonate, no robots that can send stuff flying) example: most 'street fights']
o B: Good Protection (no robots that require pre-approval, roughly 1/4" polycarbonate or better all around)
o A: Better Protection (no limitations, but pre-approval required over certain limits) [example: the COMBOTS arena]
o This letter rating plus a max weight rating and an ICE note, this way an event like COMBOTS would rate themselves 'A-440-ICE' (440lbs includes the walker bonus.) Whereas SACBOTS would also be an A rated arena but only for 3 pounds and no gas engines and would look like this... 'A-6' (also including the walker bonus)
o Note that an arena receives a rating based on its 'worst' element. If it has A rated sides, but no roof, it is rated a C.

As stated at the top the standards are merely for EOs to describe their arena to potential combatants and advise them as to what can or cannot be run.
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Post Wed Feb 07, 2007 3:44 pm 
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Rotwang
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One of our EO’s Daniel Marshall has done some tests on different types of pollycarb.
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Post Wed Feb 07, 2007 6:54 pm 
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