The Trebucard is a business card sized mini trebuchet. It is designed to fire jumbo paper clips and uses 16 pennies as a counter-weight. Unlike a traditional trebuchet the Trebucard uses the surface it is resting on as a pivot rather than being mounted on a frame.
See a demonstration of the card here:
And here is a video that shows you how to make your own:
See a demonstration of the card here:
And here is a video that shows you how to make your own:
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Signing UpStep 1: Download the design files
Download the design files for the card in whatever format is easiest for you to work with.
If you have any problems with the Instructables attachments the files are also available here: http://www.thingiverse.com/thing:16735
If you have any problems with the Instructables attachments the files are also available here: http://www.thingiverse.com/thing:16735
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Most of the applications I can think of are indoors anyway (sinking paperclips in your boss's coffee).
A couple of rules of fun, sorry THUMB!
In a conventional trebuchet, The Counterweight should be about 100 times the weight of the Projectile, the Arm should balance at the pivot when not loaded, and the pivot point is about 1/4 of the length from the counterweight end. Maximum efficiency is achieved if the weight is permitted to fall in a straight line.
Not sure how that might translate to your rocker design but I'd like to see some variations. Let's see if I can find some heavy Card...
From my experimentation one of the important things about this rocking design is to have the CG of the counterweight as close as you can get it to the edge of the rocker so that it is as close as possible to the ground as the projectile is launched. I do have a variation which is more optimized in this regard.
Also a grippy surface without any slipping will help performance. Which seems to deviate a bit from that straight line principle in conventional trebuchets. But if you think about it, it makes sense because with the way the card rocks the counterweight's speed relative to the ground will be slowest as it reaches the lowest point. In the ideal scenario where the counterweight is at the very end of the trebuchet and in contact with the ground with no slippage at the time of launch then the speed of the counterweight relative to the ground would be zero which is exactly what you want. Although unless you have an infinitely dense material you will always have some speed relative to the ground and some angular momentum that won't be fully used.
But I do think you could get some pretty good efficiency out of this design with a dense counterweight and making the rest of the device as light as possible. One bad thing is that it doesn't scale well. Anything beyond what one or two people could lift would have to have a big frame to lift and support it for launching. But I've been thinking about trying to scale it up to golfball size projectiles and seeing how well it works on a medium scale.
For comparison the Cardapult V2 launches the same size paper clip about the same distance, but requires about 3x the energy input.
It can also be useful for demonstrating principles of physics like conservation of energy. The energy from dropping the relatively heavy weight of the pennies a few inches is used to launch the lighter projectile several feet.
This is just a scaled down and highly simplified version.
Thanks for the vote.
Although svg is probably a bit easier to edit if you need to make changes and works with the free program 'Inkscape'
And what a great idea to promote a company.
I hope you don't mind if I use it to make my own?
Thanks a lot, I think this is wonderful.
I will now have to go and have a look what else you posted. It is always a pleasure to see somebody being creative.
I've been waiting so long for another Clide Card, and here one is :)