Question for the Storm the Castle buffs :)

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UQOnyx
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Question for the Storm the Castle buffs :)

Post by UQOnyx » May 24th, 2013, 5:57 pm

Hey guys!
I was building a FAT Trebuchet for fun as a science project, and a came across a problem that I need help with. I built nearly everything, but there is one detail that no matter what I do, it has a shortcoming. I have tried to construct the wheel (fulcrum on the rollers) in different ways but none of them work. I used a cold-cut steel rod, attached to two scooter wheels, but my problem was that since the rod was too thin and the wheels too narrow, so the axle kept getting too misaligned. I also tried using two castors, but at certain points, the castors would tip over, because the lip of the metal housing was in the way, and the arm makes the castors flip over. Any opinions for what you did that might help me?
Thanks, I really appreciate it :D
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2012 Events:
Forestry
Storm The Castle


2013 Events:
Boomilever
Shock Value
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Re: Question for the Storm the Castle buffs :)

Post by plaid suit guy2 » May 24th, 2013, 7:12 pm

go to ACE and buy roller bearings and a aluminum rod to fit in them. You will never have these problems again...Ever.
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Nationals 2012:
Sound of Music: 8th

Nationals 2013:
Remote Sensing: 1st
ELG: 1st
MagLev: 6th

State 2014:
Boomi: 1st (scored 1824)
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6th: 1
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Re: Question for the Storm the Castle buffs :)

Post by UQOnyx » May 24th, 2013, 7:29 pm

Cool! Thanks for the help!
Also, how would you connect the aluminum rod to the arm?
Noor-ul-Iman School

2012 Events:
Forestry
Storm The Castle


2013 Events:
Boomilever
Shock Value
Forestry


I know the voices aren't real, but they have some great ideas..

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Re: Question for the Storm the Castle buffs :)

Post by plaid suit guy2 » May 24th, 2013, 7:52 pm

you kinda just do it...
give me a minute...
Just got back from looking at mine, take a piece of wood, drill a hole in it the exact size of the OD of the bar, maybe 1/64 smaller, and then just shove the bar in there. Nothing says that the bar has to actually rotate with the arm, it just has to support it.
blue and yellow plaid suit
Nationals 2012:
Sound of Music: 8th

Nationals 2013:
Remote Sensing: 1st
ELG: 1st
MagLev: 6th

State 2014:
Boomi: 1st (scored 1824)
Circuits: 1st
Compound: 3rd
Malgev: 1st
MP: 2nd

total gold: 18
total silver: 10
total bronze: 5
6th: 1
Poudre High School class of '15

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Re: Question for the Storm the Castle buffs :)

Post by UQOnyx » May 25th, 2013, 8:21 am

Let me try to get this straight. Buy aluminum rods, etc. Drill aluminum rod "through" block of wood, and attach arm onto block of wood?
Also any ideas on what size or type to get?
Noor-ul-Iman School

2012 Events:
Forestry
Storm The Castle


2013 Events:
Boomilever
Shock Value
Forestry


I know the voices aren't real, but they have some great ideas..

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Re: Question for the Storm the Castle buffs :)

Post by iwonder » May 25th, 2013, 8:55 am

I've got an F2K design, but it's pretty close to the same thing. It's got a guide piece on the front cross strut(the piece the arm rests on when cocked. And I put half round wood or plastic down the inside of the track, just barely wide enough for the wheels. Never had a problem with it(I've built a couple of them, one being a 8 foot tall treb with 50lbs counterweight). Also, if it's really an issue, you can put the counterweight in the middle and run the axle that's normally used for weights down guide rails with slots cut in them, but that's a little complicated. Getting the arm to stay aligned is always the problem though ;) I can post pictures of the smaller one I've got if you want.
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Re: Question for the Storm the Castle buffs :)

Post by UQOnyx » May 25th, 2013, 10:26 am

Yeah, that's been my problem to, keeping the arm aligned. If you do have pictures, I would really appreciate it :D . If i just add two blocks of wood to the side of the arms where the holes are drilled, it would make the holes longer, and make the axle/guides more rigid, if you know what i mean, so it wouldn't be too rickety. Would that solve my problem of the arm swaying from side to side?
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2012 Events:
Forestry
Storm The Castle


2013 Events:
Boomilever
Shock Value
Forestry


I know the voices aren't real, but they have some great ideas..

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Re: Question for the Storm the Castle buffs :)

Post by iwonder » May 25th, 2013, 10:30 am

Most of the time I solve that with the half round guides on the track and pushing the counterweights snug to the vertical supports. Is this one where the wheels start above the track(F2K) or on the track(FAT)

Here's the link to the pictures:

http://www.cyfallsso.com/storage/StC/IMG_1130.jpg <- Overview of the treb.
http://www.cyfallsso.com/storage/StC/IMG_1131.jpg <- Overview of the treb in firing position.
http://www.cyfallsso.com/storage/StC/IMG_1132.jpg <- Alignment block at the front of the treb(keeps the arm in line until the wheels hit the track)
http://www.cyfallsso.com/storage/StC/IMG_1133.jpg <- Half round acyclic on the rails to keep the wheels from falling on the inside(the track's wide enough they can't fall to the outside).
http://www.cyfallsso.com/storage/StC/IMG_1134.jpg <- Looking down the vertical support you can see the counterweight axle and the slot cut in a 1x2 to align the back of the arm.

It's not entirely finished yet, the other side of the track that's curved isn't attached to anything yet, and I don't have a sling or firing pin on the arm, but initial dry runs with weights have been good, the arm's never even shown signs of misalignment.
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Re: Question for the Storm the Castle buffs :)

Post by plaid suit guy2 » May 25th, 2013, 12:03 pm

mine never had alignment problems. you just make the hole and then shove the bar through the hole. flat guides and it will do it's own thing, but it always turns out right in the end
blue and yellow plaid suit
Nationals 2012:
Sound of Music: 8th

Nationals 2013:
Remote Sensing: 1st
ELG: 1st
MagLev: 6th

State 2014:
Boomi: 1st (scored 1824)
Circuits: 1st
Compound: 3rd
Malgev: 1st
MP: 2nd

total gold: 18
total silver: 10
total bronze: 5
6th: 1
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Re: Question for the Storm the Castle buffs :)

Post by UQOnyx » May 30th, 2013, 4:57 pm

Thanks for the pictures and everything guys! I apologize for the late response but it has been a hectic week :D. So we built it, finally.They didn't sell roller bearings at ACE, but the guy told us to take two lag bolts, pre-drill, put epoxy in it, and put the scooter wheel through it and the lag bolts on either side. It turned out a bit crooked but it worked. We tested, with an arm ratio of 2:1. We fired from 1.5 ft. up with a CW of 5 lbs. Our highest score so far was 30 feet 8-) . Not sure if too good, so you guys can tell us, but I'm pretty proud anyways considering last year's results (highest was 11 ft. lol).
Noor-ul-Iman School

2012 Events:
Forestry
Storm The Castle


2013 Events:
Boomilever
Shock Value
Forestry


I know the voices aren't real, but they have some great ideas..

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