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Has anyone here ever built a catapult for assistance with jumping? If so, please PM me. I don't need something too powerful, just something that can throw me about 20 to 50 feet.

god i love the posts i read on here sometimes

I think a trebuchet would be a better siege weapon to use.
http://www.youtube.com/watch?v=67fFDiPRsrk

False. Trebuchets have a very very high malfunction rate.

Think about the sling not detaching and getting slammed into the ground. On top of a huge possibility of bad exits.

Not a good idea.

Malfunction rate will be a derivative of materials used, fabrication techniques and end user stupidity.

I've built and used a good chunk of back yard siege weaponry myself. The best performer, by far, was the floating arm trebuchet.

Seeing as the OP is not worried about distance, the sling is not needed. Just place a chair on the end of the arm.

I personally will put my trust in gravity. If someone else wants to trust springs or twisted rope more, so be it.

Right on. I have a floating arm treb sitting in my backyard. Small scale... always wanted to build a large scale. I am assuming you have?

I showed the OP a site where the guy build a treb with a chair at the top. Worked pretty well for exactly what the OP needs, until it collapsed. Only problem is it would have to be massive. We are talking 1800-2000 pound counterweight. Not very practical at all, unless we all chip in to build a heavy duty one at the top of one of the exit points in norway.

Jason (428) has been hinting about building one recently. Post 24 has what I would assume to be the counterweight.

http://www.basejumper.com/..._reply;so=ASC;mh=25;

Oh, so this is a bridge day thing too? Even better. That picture looks like it could be a compressed air tank? That would be sweet as well... I've seen some pretty impressive air cannons.

A 500 pound counterweight won't be enough for a catapult though. That will be about a 5 to 2 counterweight to payload ratio when you need about 10:1 or higher.

I'm no engineer, but do you really need that much weight just to get someone off a bridge? I mean its not like they need to design something that can throw someone to the Fayette station bridge.

Also, from a logistics standpoint, i doubt it will ever happen at bridge day, but I am keeping my fingers crossed!

"Safely" off a bridge, yes. I wouldn't want to have any less and have people getting 10 feet or less clearance from the thing. You want to aim on the powerful side due to jumper weight difference. (Think if you build it for a 140 pound person and a 200+ pound person gets launched.)

Who knows? It's possible! That would defiantly make it more spectator friendly.

http://www.youtube.com/watch?v=-wVADKznOhY

Skip to 1:55. That's what we need! Load up a car with a few buddies, get launched and bail before you hit the bottom.

Sort of like this...
http://www.youtube.com/watch?v=GMxXHY1f8Xk

Sounds like that guy is underwhelmed at his current one, maybe we can just buy his! Hell if we told him what we wanted to do maybe he would give it to us.

I think I heard it cost 50,000 pounds. Let's start a fund.

PM sent

Jean-Marc Mouligné (BFL#113) had built a catapult and put a couple of jumps on it (around 300ft)

http://www.hommevolant.fr/...evolant/Accueil.html

Working on it right now. Many parts already procured. Solidworks 3D CAD models in progress. Should be done soon.

BD 2011 right? We could get a big box truck and cut the top off. Drive over the bridge and at the right place, get launched out if the truck and over the side of the bridge. I'm in!

>>Has anyone here ever built a catapult for assistance with jumping?<<

Just for historical reference the first BASE "catapult" launch (I know of) was David Nunn at the sub-300-foot Freedom Bridge in San Diego, CA in the early 90s. I don't recall if it was pneumatic or spring loaded but he mounted it in the back of a pick up truck and it launched him handily over the rail as the truck crossed the bridge. Basically it was just a metal plate he stood on until it fired.

NickD

Is this what you are looking for?

http://www.youtube.com/...&feature=related

Or this http://www.youtube.com/watch?v=mqtGhdTKe9w

nope we only need to clear about 40 feet horizontal

this looks fun:

http://www.youtube.com/watch?v=_o34YdqsL6w

This should do the job with a slim jumper http://www.youtube.com/watch?v=MXgstr7x4AQ