| Infernal Contraption | |
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+5Josh Raichel Cody Dan Curhan donsun Jeff L 9 posters |
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Jeff L Minister of Silly Walks
People Skills : 6576 Registration date : 2009-03-14 Age : 35 Location : Miami, FL / Atlanta, GA
| Subject: Re: Infernal Contraption Thu Aug 06, 2009 9:28 pm | |
| I'm not going to use the full-body/shell drum design (drum with wheels) because I couldn't fit the weapon motor along with everything else inside the drum. Since Infernal Contraption hasn't gotten beyond CAD models, I'm referring to them as v0.'x' (since they never became physical robots). v0.3 will be a standard drum-bot layout, with only a slightly larger diameter for the drum than normal. In the end this may be a wiser decision than using a more radical design, since simpler robots break much less frequently than complex robots.
Last edited by Jeff L on Fri Aug 07, 2009 1:00 am; edited 1 time in total | |
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rjw Chief Bottle Washer
People Skills : 7766 Registration date : 2009-03-31 Location : Miami
| Subject: Re: Infernal Contraption Fri Aug 07, 2009 12:05 am | |
| Sorry to hear that things didn't work out with the drum on wheels design.
I had a somewhat different design for one a while back, but got sidetracked to other stuff....maybe 1 day I'll get to it.
So how big and heavy is the drum on you conventional bot or V0.3 ....???
Some times things change for a reason | |
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Jeff L Minister of Silly Walks
People Skills : 6576 Registration date : 2009-03-14 Age : 35 Location : Miami, FL / Atlanta, GA
| Subject: Re: Infernal Contraption Fri Aug 07, 2009 2:59 pm | |
| v0.3's new drum: It weighs around 2 1/4 pounds right now, but it'll probably end up around 3 pounds once all the fasteners, counterweights and mounting parts are included. I can probably add even MORE tungsten rods after it's balanced to make it around 4-5 lbs, but it's so simple to do that I'll just come back and use whatever spare weight I've got on that after the chassis is done. The drum's diameter is 2.5", 3" diameter with the tooth. Fun Fact: Inventor has no entry for Tungsten in its materials library, so I've been using rods made of solid Gold as a substitute, since gold and tungsten are ALMOST the same weight & density. | |
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Jeff L Minister of Silly Walks
People Skills : 6576 Registration date : 2009-03-14 Age : 35 Location : Miami, FL / Atlanta, GA
| Subject: Re: Infernal Contraption Sat Aug 08, 2009 3:08 pm | |
| After running some calculations, I've determined that I can still squeeze 10-11 kilojoules out of this smaller drum. The main difference is it'll need to be spinning at 38,000 rpm, just 100 rpm shy of hitting the 500fps RFL barrier for tip speed. Again, the weight for these numbers is 4 lbs. I can hit 16,000+ 16+ kilojoules with 45,000 rpm for the BotsIQ competitions.
Last edited by Jeff L on Sat Aug 08, 2009 11:52 pm; edited 1 time in total | |
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rjw Chief Bottle Washer
People Skills : 7766 Registration date : 2009-03-31 Location : Miami
| Subject: Re: Infernal Contraption Sat Aug 08, 2009 10:30 pm | |
| - Jeff L wrote:
- I can hit 16,000+ kilojoules with 45,000 rpm for the BotsIQ competitions.
I'd like to see that in a 15 lbs. bot...... And the structure to support this is made of...? Drive motor and bearings for 45k rpm's ? Very Curious ... | |
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Jeff L Minister of Silly Walks
People Skills : 6576 Registration date : 2009-03-14 Age : 35 Location : Miami, FL / Atlanta, GA
| Subject: Re: Infernal Contraption Sat Aug 08, 2009 10:41 pm | |
| I'm using the same weapon motor I had intended to use for the full-body drum (v0.2) design. It's a large outrunner intended to be used in RC helicopters, with around a 1500W (around 2 horsepower) output. | |
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Jeff L Minister of Silly Walks
People Skills : 6576 Registration date : 2009-03-14 Age : 35 Location : Miami, FL / Atlanta, GA
| Subject: Re: Infernal Contraption Sat Aug 08, 2009 11:54 pm | |
| - rjw wrote:
- Jeff L wrote:
- I can hit 16,000+ kilojoules with 45,000 rpm for the BotsIQ competitions.
I'd like to see that in a 15 lbs. bot......
LOL. TypoFAIL, DESTRUCTION WIN | |
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Will Bales ULTRA contributor
People Skills : 6164 Registration date : 2009-03-15 Age : 31 Location : Miami, FL
| Subject: Re: Infernal Contraption Sun Aug 09, 2009 12:07 am | |
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rjw Chief Bottle Washer
People Skills : 7766 Registration date : 2009-03-31 Location : Miami
| Subject: Re: Infernal Contraption Sun Aug 09, 2009 1:45 am | |
| - Jeff L wrote:
- rjw wrote:
- Jeff L wrote:
- I can hit 16,000+ kilojoules with 45,000 rpm for the BotsIQ competitions.
I'd like to see that in a 15 lbs. bot......
LOL. TypoFAIL, DESTRUCTIONWIN Actually, even at 15k joules, I'd like to see a 15 pund structure that would not self-destruct, should that energy level be reached and applied against anything... Also, 45k rpm's might be beyond what any bearings capable of withstanding the forces would want to spin ...not to mention a pretty stout motor. Ask me how I know..... | |
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Cody 2000+ club
People Skills : 7813 Registration date : 2009-03-16
| Subject: Re: Infernal Contraption Sun Aug 09, 2009 2:25 am | |
| 45k at the weapon? O how i can not wait to see this!!! haha | |
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Jeff L Minister of Silly Walks
People Skills : 6576 Registration date : 2009-03-14 Age : 35 Location : Miami, FL / Atlanta, GA
| Subject: Re: Infernal Contraption Sun Aug 09, 2009 12:37 pm | |
| Yeah, it's a just a little bit on the crazy side. But if it works, it'll pay off big time. The front of the chassis will actually slide along the floor of the arena, which simplifies the support structure immensely - I just have to make it capable of transferring force to the floor very well.
The bearings are probably going to be a wait-and-see thing, but there's a solution there as well; maybe not the best solution, but it'll work. The bearings I'm looking at are here. I've been contemplating using four or more as opposed to the typical two bearings, and looking at the best method to mount them. I'd prefer to press fit them into the chassis, but I'm probably going to need to put a silicone or rubber gasket around them to help absorb the shock of an impact. Fortunately, McMaster-Carr sells O-Rings of the exact size I would need. | |
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rjw Chief Bottle Washer
People Skills : 7766 Registration date : 2009-03-31 Location : Miami
| Subject: Re: Infernal Contraption Sun Aug 09, 2009 1:13 pm | |
| fwiw: 4 of those bearings wouldn't handle 1k joules......
also , think about it 1/2" od, 5/16 shaft , then you have the inner and outer races...balls must be maybe 1/16 or less in diameter.
I wouldn't cut a single part until I had a handle on supporting the loads.....
It might be wise to consider a MUCH larger shaft as well (to start with)
jmo...trying to help | |
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Jeff L Minister of Silly Walks
People Skills : 6576 Registration date : 2009-03-14 Age : 35 Location : Miami, FL / Atlanta, GA
| Subject: Re: Infernal Contraption Sun Aug 09, 2009 1:52 pm | |
| how about this one: http://www.mcmaster.com/#2385k43/=3463xz Two would get me a radial load capacity just shy of 3,000 lbs, with a 17mm grade 5 Ti shaft. | |
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Dan Curhan Admin
People Skills : 6368 Registration date : 2009-03-14 Age : 32 Location : Sarasota, FL
| Subject: Re: Infernal Contraption Sun Aug 09, 2009 4:13 pm | |
| those look a lot better. The first ones would definitely be WAYYY too small. I've used Mcmaster's miniature precision ball bearings before and they're really fragile. Even a push fit that isn't perfectly executed will screw them up and make them click and stuff.
you do realize, though, that the second bearing you picked out are almost $200 each?!!! if you can afford it, they look okay, but I think these are better:
http://www.mcmaster.com/#6660k15/=347qkg
They're what I would use. They've got a load rating 1000 lbs higher, and can handle misalignment. Since you're putting your bearings in the frame, and you're using the frame as your front runners, you want something that can handle some misalignment. There are some nasty undercutters in the 15 lb division, and if your frame gets bent and you have to bend it back, it's unlikely that you can get it back so that the bearings are perfectly aligned. These bearings can also run at a higher temp, so you can spin them faster than 24K rpm - you just shorten the lifespan. The ratings are given such that the bearing life is guaranteed for 100 million revolutions provided you stay within the rated specifications. You're not gonna get 100 million revolutions out of these if you spin at 40K rpm, but they're not gonna explode or anything. Plus, they're a lot cheaper, and they're wider - they're more than 1.5 times the width, so there's more support.
The bearings you picked out were ABEC-7. That's why they're so expensive. The ABEC rating has nothing to do with durability, or capacity, or even spinning friction - it's how perfectly concentric it spins. You don't need anything fancy or exotic to support your shaft - one hit and it's probably not ABEC-7 anymore anyways.... | |
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Cody 2000+ club
People Skills : 7813 Registration date : 2009-03-16
| Subject: Re: Infernal Contraption Mon Aug 10, 2009 1:50 am | |
| Please keep in mind that huge weapons arent everything. Driving is a key factor in this sport, plenty robots have more power then ours or wills but they're terrible drivers and/or have poor strategies | |
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Will Bales ULTRA contributor
People Skills : 6164 Registration date : 2009-03-15 Age : 31 Location : Miami, FL
| Subject: Re: Infernal Contraption Mon Aug 10, 2009 1:57 am | |
| YES! driving is VERY IMPORTANT!!!! | |
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Jeff L Minister of Silly Walks
People Skills : 6576 Registration date : 2009-03-14 Age : 35 Location : Miami, FL / Atlanta, GA
| Subject: Re: Infernal Contraption Mon Aug 10, 2009 11:48 am | |
| - Cody Harris wrote:
- Please keep in mind that huge weapons arent everything. Driving is a key factor in this sport, plenty robots have more power then ours or wills but they're terrible drivers and/or have poor strategies
I know, I'm just solving the problem of "how do I get this thing to not make itself explode when it hits something" right now [with every action, there is an equal and opposing reaction]. I haven't forgotten that you need to be able to actually drive to compete well. | |
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Jeff L Minister of Silly Walks
People Skills : 6576 Registration date : 2009-03-14 Age : 35 Location : Miami, FL / Atlanta, GA
| Subject: Update 9/6/2009 Sun Sep 06, 2009 2:10 am | |
| Infernal Contraption is now on hiatus until further notice. Reason will likely be posted within the month . | |
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