Trajectory B/C

[Navid10]

Have you started calibrating your machine yet?

[binary010101]

We are going to build a torsion spring for the catapult with nylon or manila rope. I'm just wondering, what is the efficiency of torsion springs compared to elastics?

[starpug]

Should i Put the Bungee Cords on top for tension or on the bottom? I am only shooting for a basic design so the best one would be nice but it'snot that big of a deal!

on top I think. I don't exactly know what you are talking about

The Rules are pretty helpful but im not sure if i need to get this serious since it is a school project

So you are not actually on SO, you are just here getting help for a school project

[trombonegirl23]

In my experiences Surgical tubing and bungee cords have not been reliable at ALL. The results I got were never the same and one day it could fire 10 feet the next day it went 2 inches. Last year using the surgical tubing we made a cannon, which failed us because it was not constant. The year before we made a catapult with the bungee cords which also failed us after days of practing. My question is what is reliable and will not change. I have been thinking about this for a long time but can't think of anything, besides rubber bands which don't seem like they would be a good idea at all. And suggestions?

[starpug]

In my experiences Surgical tubing and bungee cords have not been reliable at ALL. The results I got were never the same and one day it could fire 10 feet the next day it went 2 inches. Last year using the surgical tubing we made a cannon, which failed us because it was not constant. The year before we made a catapult with the bungee cords which also failed us after days of practing. My question is what is reliable and will not change. I have been thinking about this for a long time but can't think of anything, besides rubber bands which don't seem like they would be a good idea at all. And suggestions?

Resitence tubing e.g. excercise tubing, read a page or so back for a small discussion of it.


If you wanted to go with a design where the arm is the source of the power I've heard that Carbon fiber is pretty consistent.

[andrewwski]

We used surgical tubing last year, it was pretty consistent. But as with anything, surgical tubing comes in many different variations.

[trombonegirl23]

Is excercise tubing changed when exposed to light or heat? I thought before someone was saying certain colors of surgical tubing would be affected more when they got warmer or exposed to more light. Is one color of excerise tubing better than another if they are of the same strengh?

[Zaizen_Kaegyoshi]

Hello
I am building something for Trajectory and me and my teammate decided on catapult or ballista. which one should we choose?

[starpug]

Hello
I am building something for Trajectory and me and my teammate decided on catapult or ballista. which one should we choose?

What are some good websites that you can find good designes for catapults

You happen to be on it
Gallery of Trajectory Devices http://gallery.scioly.org/categories.ph ... d69aa3a001
Best B Devices at Nats [wiki]The Best of 2009#Trajectory_B[/wiki]
Best C Devices at Nats [wiki]The Best of 2009#Trajectory_C[/wiki]
Notable devices
My devices from the past two years 164|2/a2j_IMG_0021.jpg and 976|2/a2j_img0154oqu.jpg
Aia's device 1832|51/IMG_1799.JPG note: there are more pics of this in the gallery
California States B Division Winner 1046|2/a2j_IMG_0199.jpg
Misc devices 1035|2/a2j_IMG_0181.jpg, 1034|2/a2j_IMG_0180.jpg, and 1530|2/Trajectory_2009NSO (45).jpg

You should do a little brainstorming an you can use these pictures to give you ideas and to get you started. If you want some info on some other different kinds of designs, maybe you should research medieval catapults (make sure they are elastic driven.)

This should help Kageoshi

Is excercise tubing changed when exposed to light or heat? I thought before someone was saying certain colors of surgical tubing would be affected more when they got warmer or exposed to more light. Is one color of excerise tubing better than another if they are of the same strengh?

I believe I was saying that, but a simple simple sun shade and the problem is solved.

[AlphaTauri]

Does anyone know a way to downsize catapults?

What I mean is, my team had a really good catapult last year but it probably won't fit into the 70cm cube this year. So are there any effective ways to make it smaller so I don't have to build a new one? (Yes, I'm lazy.)