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weight probs
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bigjimmy



Joined: 18 Jun 2004
Posts: 40
Location: New South Wales


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weight probs

hey everyone.

Im wonderin how many light weight bots there are in NSW. Im havin a fair bit of weight trouble with my featherweight bot(i dont think anyone would let me enter a 17kg bot in feathers?? Confused ) so ive been thinkin(that hasnt happened in a while)........ would it be worth makin it a light weight, cause the design needs the strong meterial for it to work and be relaiable. then i could add some real thick armour, better batterys, stronger motors etc or i should just change the design and use weaker materilas(ill still have my spinner though Twisted Evil ) i think i have a pic of it ill try and put it up when i find it.

but obdiously it wouldnt be worth it if ther was only like 2 lightweights in NSW...

just another thought, wouldnt it be cool if we made it 15kg for the feathers(i think ive seen a forum for this befoere ABBL went down)

Post Wed Jul 07, 2004 3:21 pm 
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Karmond



Joined: 16 Jun 2004
Posts: 97


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I don't like the whole 15kg option. People are just suggesting it because it suits them better, which is not what we want. We don't want to bend the rules to suit every competitor... what happens when we go up to 15kg? Will people start making 16kg bots and then complain?

I suggest you make some changes to lighten your robot, or add some more and make it a lightweight. Nick is building one... You'll have lots of fun with his bot haha. Smile

Post Wed Jul 07, 2004 5:36 pm 
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Nick
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Joined: 16 Jun 2004
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Location: Sydney, NSW


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Yeah, if my featherweight doesn't take up all my time before Marayong, I will bring Artemis along for a non-combat demo. I will put up a few photoes once my home internet gets reliable enough.

I fully agree with the weight limit, but perhaps we could look at a special open class, where you put in anything you can, perhaps in a mini annhilator format or smash-up derby? It would have to be an occasional event so we don't get distracted from the main comp.
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Post Wed Jul 07, 2004 5:55 pm 
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chris



Joined: 18 Jun 2004
Posts: 160
Location: Brisbane


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an open class? why does the image of a car running over a featherweight come to mind when you say that?
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Post Wed Jul 07, 2004 6:08 pm 
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DumHed
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Joined: 29 Jun 2004
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Location: Sydney


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I'll bring the car!! Cool
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Post Wed Jul 07, 2004 6:11 pm 
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chrisjon65
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Joined: 15 Jun 2004
Posts: 754
Location: blaxland


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people are aware how i feel about the 12.999 kg limit but i do build within it ...just Wink .....dont worry lightweights will be the next in thing soon enough as soon as an arena can take them ..so build a featherweight ,learn your craft, and then build a lightweight Very Happy
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Post Wed Jul 07, 2004 7:05 pm 
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andrew



Joined: 16 Jun 2004
Posts: 3110
Location: Castle Hill, Sydney. N.S.W


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Well Jimmy,
Its not our fault u built your robot to be over weight. U can either lose heaps off it which will be a mongrel or upgrade it to a lightweight and abuild another featherweight in 12 kg.

I think the limit should stay at 12.99 for featherweights and i will also build me a lightweight one of these days if possible. Looks like fun.
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Post Wed Jul 07, 2004 7:59 pm 
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colin



Joined: 16 Jun 2004
Posts: 102


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quote:
Originally posted by andrew:
I think the limit should stay at 12.99 for featherweights and i will also build me a lightweight one of these days if possible. Looks like fun.


I think its time the limit is brought down to the proper 12kg, all it means is that rather than weighing 12kgs on your dodgy bathroom scales, it needs to weigh 11. If there is not going to be a move back to the actual weight limit, maybe we should change the limit?

Post Wed Jul 07, 2004 8:09 pm 
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Spockie-Tech
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Joined: 31 May 2004
Posts: 3160
Location: Melbourne, Australia


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I'm with colin.. I want to see the 12Kg limit tightened up, not relaxed.

Sorry for all you guys who are having trouble building to the weight limit, but if gary can build bots over a meter on a side that are still 12.99 legal (and in most cases, even 12.2 legal, which is the international standard), then surely you can too..

Even Tim with his indestructible 4WD steel brick managed to get it all under the weight limit.

I know some of you guys start building first and weigh later, but if you start asking for extra kilo's now, are you going to be happy to face the nasty spinners like Basilisk and Annihlation when they use the extra weight to pack in even more power ?

If you cant build to 12Kg, then build a lightweight (25Kg) non spinner. You wont have too many people to fight to start with, but at least the existing arena's should have a chance of coping with non spinner 25Kg bots.

Post Wed Jul 07, 2004 10:50 pm 
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Ajax
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Joined: 17 Jun 2004
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Location: Sydney


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I'm with Colin & Spockie.

We should be sticking to the weight limit and not increasing the limit.

Every one needs to take the weight limit into account when building. If it is to heavy then you will have to make a choice.

Reduce Armour or Reduce Weapon.

My personal thought is to stick with the International weight limits. This will mean there is no issues for people from other countries to come over and compete here or we go over seas.
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Post Wed Jul 07, 2004 11:44 pm 
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Nick
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Joined: 16 Jun 2004
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Location: Sydney, NSW


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If you build first and weigh later, you're doomed to a compromised design that will never be a winner.

Almost nobody has decent scales and here is how I get around it:

Keep a spreadsheet parts list with the weight and cost of every tiny part from the very start.

Get a cheap but accurate 2kg digital scales from Jaycar or a similar place - most individual parts for a featherheight weigh less than 2 Kg.

Use one of the many on-line weight calcs to estimate what chassis parts will weigh before you cut them.

Use more plastic inside - UHMW plastic is magic stuff, just ask anyone who has a set of my motor mounts Wink
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Post Thu Jul 08, 2004 12:40 am 
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mytqik



Joined: 26 Jun 2004
Posts: 127


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UHMW (ultra high holecular weight, also called umpy) plastic is used as a wear lining on material handling applications. eg inside hoppers & gob hoppers in quarries & cement plants. These guys always have offcuts so they would be a good source of small pieces. It is very easy to machine & can even be taped or use helicoils.

Also G10 as used on printed circuit boards & sailing fins awould be a good source of armour.

Also if you have access to a 3D drawing package (solidworks, solidedge, Pro E, Rhino), you can model your robot before building. Can save alot of fabrication time. You can also apply material properties to individual components & get an accurate weight.

Post Thu Jul 08, 2004 12:47 am 
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Ajax
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Joined: 17 Jun 2004
Posts: 298
Location: Sydney


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'mytqik' & 'Nick' have very good points and realy should be followed.
first rule of robot building, lay out every thing that is to go into your bot.
Second rule of robot building,Weight everything that will go into your bot before assembly, to confirm weight.

I bought a set of 3Kg scales, and I'm weighing every thing and putting it in to a database for future referance. And I mean every thing, Nuts Bolts, Washers, wheels, Motors, Batteries, etc.

Then I place exatly what is going in to the bot into a BOM (bill of materials)
and the weight is calculated.

Also I am designing every thing In SolidWorks. (Will be changing to Inventor soon) making a complete assembly drawing with every thing in it's place.
In cluding the Electronics. (I do mean the wires as well.)

So when it is being assembled, I am not going to get any surprisses.

This is a little over board, But the weighing of all the parts before assembly is a definent to do item before starting.
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Post Thu Jul 08, 2004 1:22 am 
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mytqik



Joined: 26 Jun 2004
Posts: 127


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Modelling your robot in 3D has a couple of advantages.

1) It should ensure that your final design comes in at the correct weight
2) It allows you to try different designs/combinations without actually spending any money/time in fabricating something that "may" work
3) It allows you to visualise the fianl design. This always helps the construction process.
4) Any parts to be made externally (laser cutting, CNC machining) can be detailed & provided to the company so that you get what you want, with no confusion.
5) The final design can be rendered. This allows you to print it out & take to potential sponsors so they know what they are getting for their sponsorship dollar. Much more professional than a sketch on the back of an envelope.

I would strongly recomend trying out these software packages if you can get access to a machine. If not, let me know & we may be able to sort something out.

Post Thu Jul 08, 2004 3:50 am 
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andrew



Joined: 16 Jun 2004
Posts: 3110
Location: Castle Hill, Sydney. N.S.W


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Yeah well i guess we should start getting serious huh. Oh wel looks like scraps saw will be 12 volts then if need be. That will easily get my under 12 kg.
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Post Thu Jul 08, 2004 9:09 am 
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