pic: "You should never go against a robotics kid"

[Eugene Fang]

That thing make the most awesome swishing noise when it fires. It was like a knife through air, and was one of the quietest catapult there, though it went the furthest.

It uses a 25/32 inch steel axle and car bearings.

[colin340]

yeah there a big spread in most tech class projects from robotics kids a not yet robotics kids

[NickE]

A video would be awesome (if possible)

[AndyB]

I've died and gone to surgical tubing heaven.

[Bannanakin]

I have a few videos from testing, but i need to get them on my computer, so i will problably upload them to youtube by the end of the week.

[martin417]

Not to be stickler... ok, yeah, I am . That thing looks a lot more like a trebuchet than a catapult. Remember, engineers must always be precise in communication.

Anyway, awesome job! The physics classes at my kids' school also have a project to build a "device" to launch a tennis ball and hit a target 20 feet away (30 for honors, variable distance for AP, accuracy counts) Requirements were 2' x 2' base, no part may extend above 1 meter at any time. last year, one of the classes put a spin on the project and said shoot as far as you can, bonus for more than the minimum distance. One of the robotics kids built a monster device that fired a tennis ball well over 250 feet (tennis balls don't fly as well as baseballs). Kids are still talking about that catapult.

[JesseK]

If you don't want it banned, you should have the project changed so that the students not only have to go 40-50m but also have to hit a target at that distance. That way the hard physics of calculating and attaining the necessary final speed and launch angle is thrown into the mix while also keeping such a valuable learning project in the curriculum.

This begs the question, 'Is it better to be famous, or infamous?'

[Nuttyman54]

Originally Posted by martin417

Not to be stickler... ok, yeah, I am . That thing looks a lot more like a trebuchet than a catapult. Remember, engineers must always be precise in communication.

It's not really a true trebuchet either. Trebuchets use counterweights to throw their payload, this uses surgical tubing. This does appear to use a sling however, which is a staple of trebuchets. IMHO, it still qualifies as a catapult.

[Eugene Fang]

The video has been uploaded to YouTube!

http://www.youtube.com/watch?v=p0vZhZob9lk

We will probably take some better videos (ones where you can actually see the ball) over winter break. Also, we'll try to take some at 240 fps (the max my camera can handle, though I think we need a higher frame rate) and slow it down.

[AdamHeard]

Originally Posted by Pikat

The video has been uploaded to YouTube!

http://www.youtube.com/watch?v=p0vZhZob9lk

We will probably take some better videos (ones where you can actually see the ball) over winter break. Also, we'll try to take some at 240 fps (the max my camera can handle, though I think we need a higher frame rate) and slow it down.

Based on the testing data, you logically now need to put an infinite number of loops of tubing on it.

[mrbob1000]

Originally Posted by AdamHeard

Based on the testing data, you logically now need to put an infinite number of loops of tubing on it.

building on that, you may want to replace at least some of the wood with metal for durability reasons. (eventually, the wood or the metal will fail)

[NorviewsVeteran]

call discovery channel and get the guys at time warp

[Nuttyman54]

Originally Posted by NorviewsVeteran

call discovery channel and get the guys at time warp

seconded

[Eugene Fang]

Originally Posted by Nuttyman54

seconded

I've never heard of that show before and I just watch a bit of it at discovery.com. It's really cool. We'll see if we can get this on, and see how inefficient our release angle is!

[Eugene Fang]

Hey, everyone!

We shot some slow motion videos (it moves so fast that it's still not that slow...), and we found that the catapult isn't even close to being optimized. We we hope we can push another 50 meters out of it.

See the video here:

http://www.youtube.com/watch?v=XqCeL_rW88M

(you can click "Watch in HD" on the bottom right for better quality)