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My friend and I are new to this chat room stuff, and idk if i pressed the right button, but my question is, what kinda material works well? My local hobby store said carbon fiber works for arms, but i got nothing else. can anyone help?

fishy300815 wrote: My friend and I are new to this chat room stuff, and idk if i pressed the right button, but my question is, what kinda material works well? My local hobby store said carbon fiber works for arms, but i got nothing else. can anyone help?

It really depends. Carbon fiber works well for arms, but it can be fairly expensive. I build my trebuchet out of wood. Right now my arm is also made out of wood but I plan on changing that soon.

fishy300815 wrote: My friend and I are new to this chat room stuff, and idk if i pressed the right button, but my question is, what kinda material works well? My local hobby store said carbon fiber works for arms, but i got nothing else. can anyone help?

If this is your first treb, you will probably want to build something that works but is not too expensive. You can always spend the money on another one after you have perfected some of the techniques.

I would recommend you check the WIKI. It has the instructions for the basic T shaped treb.
Also check the following site from the North Carolina Science Olympiad. It has a basic (and adjustable) T treb.
http://www.sciencenc.com/event-help/stormthecastle.php

The key difference I would make is to make the pin adjustable (forward and back not left to right). Not all pin angles work best for all projectiles.

Both of these designs are fundamentally the same. They are also proven to give you something that works.
It may also help you troubleshoot your own machine

Only those with much experience (or a whole lot of money) should work on FATs. They have great performance but have many more variable to work out.

The pictures we found of FAT trebs all show weights split on each side of the arm. The competition only allows one weight hung from the arm. It seems to us that a weight on one side only will twist the arm in the guide possibly causing it to hang or drag. How are FAT builders handling a single weight?

I have actually added an eye screw (I don't know the actual name... one of those screws that sort of makes a loop?) and then that is what you attach the weight to.

coach green wrote:The pictures we found of FAT trebs all show weights split on each side of the arm. The competition only allows one weight hung from the arm. It seems to us that a weight on one side only will twist the arm in the guide possibly causing it to hang or drag. How are FAT builders handling a single weight?

You have to make the place you're putting the weight at the intersection of the main arm and the axle for the vertical track.

Uh, so our trebuchet has hit 22+ meters (22-30) for almost every couterweight/projectile combination, I wanted to know if this would get medals at regionals... and if not, how we could improve the design.

trajectoryroxs wrote:Uh, so our trebuchet has hit 22+ meters (22-30) for almost every couterweight/projectile combination, I wanted to know if this would get medals at regionals... and if not, how we could improve the design.

How could you possibly get 20 meters with 1kg

Friedoyster3 wrote:

trajectoryroxs wrote:Uh, so our trebuchet has hit 22+ meters (22-30) for almost every couterweight/projectile combination, I wanted to know if this would get medals at regionals... and if not, how we could improve the design.

How could you possibly get 20 meters with 1kg

I think we have gotten 20 meters for almost every combination except a few that go around 17 ish but when sometimes tested go around 20. I understand what you mean, like certain combinations are physically impossible, for those we have gotten mixed results.


We have constructed a Floating Arm Trebuchet. This design commonly allows the Trebuchet to throw farther for almost every projectile/counterweight combination when compared to other designs.

edit: Let me clarify this,

The Floating Arm Trebuchet (FAT) - a trebuchet with a vertical guides for the counterweight and wheels on its arm to allow for more efficient energy transfer than the HCW.
( source: http://scioly.org/wiki/Storm_The_Castle )

trajectoryroxs wrote:

Friedoyster3 wrote:

trajectoryroxs wrote:Uh, so our trebuchet has hit 22+ meters (22-30) for almost every couterweight/projectile combination, I wanted to know if this would get medals at regionals... and if not, how we could improve the design.

How could you possibly get 20 meters with 1kg

I think we have gotten 20 meters for almost every combination except a few that go around 17 ish but when sometimes tested go around 20. I understand what you mean, like certain combinations are physically impossible, for those we have gotten mixed results.


We have constructed a Floating Arm Trebuchet. This design commonly allows the Trebuchet to throw farther for almost every projectile/counterweight combination when compared to other designs.

edit: Let me clarify this,

The Floating Arm Trebuchet (FAT) - a trebuchet with a vertical guides for the counterweight and wheels on its arm to allow for more efficient energy transfer than the HCW.
( source: http://scioly.org/wiki/Storm_The_Castle )

Well I get that, but I still don't get how you manage to get anywhere close to 20m with 1kg even with 20gram prjectiles