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RoboKid
01-26-2009, 11:16 PM
I just wanted to start a thread to get an idea of what kind of damage people are expecting to take in the hardcore weapons class. Micromaxx rockets can be devastating if used in a clever way. I have already prototyped a pneumatic weapon that fires a 15 gram projectile at 400 fps. Flamethrowers could also be extremely dangerous to exposed servos/wiring. Any thoughts?

DresnerRobotics
01-26-2009, 11:23 PM
One thing to keep in mind is that the ultimate goal is still to score hits on the target plates, not destroy the opposing mech. These machines are far too expensive to just blow up. Some damage is to be expected, but its still not Battle Bots.

Flamethrowers are mostly for show (no way to score hits), and you'll need Robogames event coordinator (David Calkins) approval before using them. They'll also need to be pretty mild (think 'overclocked' bic lighters), given that we dont want to toast the small arena we're in. In future years to come these may relax as we move to a bigger arena.

I'm looking at a CO2 powered BB rifle system and two racks of micromaxx rockets for my hardcore weapons class. This is of course pending that I'm able to get a proper set of armor to use for it. I certainly wont be walking into the Hardcore matches with lexan armor panels, I'm looking at kevlar sheet atm. Still not entirely sure mine will be situated for the hardcore class by the time year 1 rolls around, but I'm still going to try my best. I would suggest anyone planning to participate in the Hardcore class realize that this is only year 1, so you'll probably want an airsoft class weapons loadout as well, because there probably wont be too many contenders for year 1.

(Btw: I'll get to answering your email later tonight, if not morning, been swamped today)

Adrenalynn
01-26-2009, 11:35 PM
It doesn't take much Lexan to stop a 50Cal rifle round. Lexan will stop more than the equivalent Spectra. Maybe light Spectra with a Lexan trauma plate?

SteamBoat
01-27-2009, 12:58 PM
It doesn't take much Lexan to stop a 50Cal rifle round. Lexan will stop more than the equivalent Spectra. Maybe light Spectra with a Lexan trauma plate?

Just how do you know that? What experience in life did you have that imparted that factoid on you?

MArk B. (The amazed)

Promagic
01-27-2009, 03:05 PM
I certainly wont be walking into the Hardcore matches with lexan armor panels

Uhh that was my idea....*goes outback and shoots armor with a 10 pump BB gun*

:eek: Ok...nevermind

Well I don't have Kevlar or carbon fiber on hand, what about fiberglass?
How do we find the fps of our weapons?

I have heard from the "lake-mech's" that a 12 gram co2 cartridge shoots about 50 BBs, but what is the psi?


The pressure in a CO2 tank is determined ONLY by the temperature. At room temperature (70 degrees F) its about 853 psi


The pressure in a CO2 cartridge, as long as there's any liquid in it, can be calculated roughly from:
p = p0 * exp(T/T0)
where p is pressure in psi, T is temperature (Fahrenheit), and
p0 = 314.04 psi
T0 = 69.64 F This works pretty well between 0 and 80 degrees F
Pressure = 314.04^(Current temp / 69.64)


Originally Posted by Adrenalynn http://forums.trossenrobotics.com/ambience/buttons/viewpost.gif (http://forums.trossenrobotics.com/showthread.php?p=26734#post26734)
It doesn't take much Lexan to stop a 50Cal rifle round. Care to share a little info?

elios
01-27-2009, 03:19 PM
It doesn't take much Lexan to stop a 50Cal rifle round. Lexan will stop more than the equivalent Spectra. Maybe light Spectra with a Lexan trauma plate?

Have you tried... i dont think much will stop a 50cal rifle round.... i know that the US military use them for their snipers... and they can go through most walls + flesh and bone before it stops...

in what term did you mean 50cal.. high muzzle velocity... or a pea shooter that shoots half inch peas?

Adrenalynn
01-27-2009, 04:00 PM
To the second question: I own two 50 BMGs. A Barrett and an Armalite. The latter is a competition shooter.
To the first question: I've designed my fair share of bullet-resistant cameras, and have shot my fair share of stuff with the fifty'. ;). The methodology used depends upon the threat. 1.3" of laminated lexan with airgap will stop the fragmentation from the equivalent of 4300lbs of TNT at 115ft, as well as the associated 57PSI overpressure wave. [1/8", 1/2", 1/2", 1/8"] It will also stop UL752 by rating [multiple 12G slug, point-blank]

Lower threat levels: UL752 Level 5 (7.62mm fired from a traditional "sniper" rifle) 1" laminate, UL752 Level 3 (.44Mag multiple hits) 13/16" laminate, 9mm rounds are stopped by UL752 Level 1 (3/4"), ASTM F1233-93 Class II Step 5 will stop a sledge hammer, .22, .38, most .357 (1/8", 1/8") and a monolithic 1/2" will stop all impactors (like a sledge hammer), but tends to fall down to the .357.

Most of my camera designs are tested against ASTM F1233-93 Class III Step 8. I have test video around of one of the cameras being shot twice with a Browning HP 9mm and continuing to run along quite happily... They're 3/16, 3/16 laminate.

@elios: It's "illegal"** for a sniper to shoot a human with a .50. You don't snipe people with a .50, you snipe equipment. If there happens to be a person inside the uniform - they picked the wrong time to be wearing that equipment.

** I want to say that's Geneva, but it could be an amendment to the Hague. It's all mealy-mouthed-floweriness and just all kinda blends together in my memory. Been awhile since I've read the treaties...

Promagic
01-27-2009, 08:47 PM
So how do we laminate our own plastic?

RoboKid
01-28-2009, 12:37 AM
Small bickering about the resistivity of various materials to a .50 cal rifle was not my intention when starting this thread. Unless any of you plan on using 1.3" thick Lexan armor for your bot, what does it matter. As far as other materials, Kevlar is relatively cheap when we consider that it won't take too much to create armor plates.

http://www.uswebbing.biz/HTML/kevlar.html

You can find it there for under $10 a foot. it might only take three to five feet to make all your armor. I've used this webbing, laminated in aerospace grade laminating epoxy for high power rocketry and it withstands way more load than I am anticipating any of our mechs to undergo.

1/16" lexan is also dirt cheap and can be heat formed to essentially any shape. It would do well against most any BB type weapons and would stay relatively light, not to mention clear armor would be really cool.

Is there anyone else aside from Tyb that has plans for a hardcore weapons platform?

Without trying to sound too satanical, I believe the main difference between the airsoft class and the hardcore class is that contenders are able to, without guilt, balance their focus between a possible victory due to disablement of another mech and a hit points victory. In contrast, an airsoft-only mech can only focus on hit point victories, in which case a couple high ROF weapons might be the best bet, despite the one-point-per-second limit.

I like Tyb's plan for a hardcore weapons system (the use of rockets etc) because I don't think it can be assumed that a rocket pod could be optimized for accuracy as well as an airsoft or BB weapon. The intention is clearly for theater, damage, or both. I realize that these bots are expensive (I'm building one myself) but half the fun is the rush of putting your time, effort, and resources on the line when you go to compete! This competition is distinctly seperate from Battlebots BUT the builders and pilots for those machines arguably spend way more money on theirs than we can possibly expect to spend on ours and they are constantly taking beatings.

On a seperate note, I believe that everyone knows to expect damage in the hardcore weapons division and that most pilots who are even considering the hardcore weaons division are also building a compatible airsoft version. Having said that, I think the airsoft class should be early in the day and once that is completely finished, the hardcore competition should start, this would allow everyone the option of competing in both without worrying that they might not have a bot left after a match to finish the airsoft bracket.

Adrenalynn
01-28-2009, 01:02 AM
I don't believe I noticed any "bickering" - would you point that out so I can address it with my mod hat on?

All I saw were people interested in how Lexan becomes resistant to exceptional and acute forces...

RoboKid
01-28-2009, 09:36 AM
My diction aside, i was trying to redirect conversation back to a more pertinent topic.

Do you plan on entering a hardcore mech?

Promagic
01-28-2009, 12:34 PM
half the fun is the rush of putting your time, effort, and resources on the line when you go to compete!

HEAR HEAR!!

I believe building a hardcore weapon system will be more difficult then an airsoft one, so once I finish it ill adapt my proven method on the slightly larger non-magnetic ammo.
Here are my results of materials that i have around the house that could be suited to be armor.

Clear plastic: Clear Shot from 8ft away against a tree
KYDEX Thermoplastic: Brown unbent Thickness .028" from a Free sample
KYDEX Thermoplastic: Blue warped from a Free sample

On shots 1&2 against the brown KYDEX I had it laying on some poster board, on shot 3 it was laying on some cloths.
EDIT: Back to the drawing board, further testing revealed that the shots went through after all. effective only up to 3 pumps at 6ft

Other than the clear plastic, all shots where done at point blank range with my 10 pump BB rifle.

Weapon pics courtisy of cannon ideas from "rc naval combat" research

Adrenalynn
01-28-2009, 01:57 PM
My diction aside, i was trying to redirect conversation back to a more pertinent topic.

Do you plan on entering a hardcore mech?

Only if Tybs promises and crosses his heart that I will draw your bot in the first round. ;)

Let's see here, a sabboted hypodermic needle penetrator, lithium carefully extracted from a battery, and a binary injector for the water. Oh, and a good clean spark to use the hydrogen gas that is given off in the exothermic reaction.

2 Li(s) + 2 H2O -> 2 LiOH (aq) + H2(g) : Yeah, I've got everything I need for that event. :tongue:

jes1510
01-28-2009, 02:11 PM
Adrenalynn, I think you have Mech Warfare mixed up with Meth Warfare.

(Lithium is used to make meth, yeah I know that joke was a stretch)

DresnerRobotics
01-28-2009, 02:14 PM
Now now kids, no chemical weapons :p

RoboKid
01-28-2009, 03:29 PM
rules aside, a lithium injector/fume ignition weapon would be pretty cool. A conductive shell insulated down the middle with a flash cao from a disposable camera at its heart would be pretty cool. fire it from a half inch barrel and upon contact, lightning! If you want to make a good show... I think the hardcore weapons matches will be more fun to compete in. I think my approach is backwards from most. I'm designing my Mech for the hardcore class then retrofitting it for the airsoft class. Solves all my time problems because downgrading is easier than upgrading. As I said in an earlier post, it might be a good idea to host all the airsoft matches early in the competition then once that bracket is over and done with, host the hardcore competition. This would allow all competitiors to compete in the hardcore matches without fear of having bits and pieces left for the remaining airsoft matches. After hardcore is over you may have months or a year until the next time you need to have it running.

And Adrenalynn, I'll be more than happy to take you on first draw. Not that we really have much of a choice. With the limited number of hardcore entries, it would prove to be almost a sure bet regardless of any prior arrangements. We could, if you're up for it, plan an exhibition match, weapons hot, one on one...

Adrenalynn
01-28-2009, 03:50 PM
I'm game for anything. I agree that it makes sense to hold hardcore after "softcore". I'm a little up in the air for Mech Warfare - I advise a middle school for robotics competition and I'm 99.5% done with their bot(s) design (I have to create kits for them to build to stay inside the rules). I need to teach a couple classes on robotics and electronics for robotics, then I'm done. Their competition is in March, so I'm realistically only going to have a couple months to prep. That said, I'll try not to disappoint. ;)

Practically, Aramid insulates against any reasonable electrical discharge and all the stick-proof clothing (like my rattlesnake-proof boots) are aramid insulated. My slightly snarky response regarding the hypo - as well as your electrical discharge weapon would both be stopped cold by a couple ounces of Aramid fiber. It's also used in hospital gloves and by SWAT team gloves because it will stop hypos and is resistant to most chemicals. :)

RoboKid
01-28-2009, 06:28 PM
I also mentor a middle school robotics team. By mentor I think I mean supervise. They use VEX robotics kits which are more than manageable. I try to inspire an engineering mindset but let them do all the work. I also participate on a FIRST robotics team. It sounds like you and I both will be fighting for time to build (I'm still in college). I think we should just clench our teeth and make awesome mechs. The hardcore competition sounds like a lot of fun but, as I said, I will also have an adaptable airsoft weapons platform to be able to compete with more people.

I won't disclose my most secret and clever weapons :) that make it too easy for you all.