Step 7: Insert the Counterweights Into the Card

Then you simply insert your stack of coins into the slots you cut out of the card. They go in on the side opposite of the way the other parts are folded.

The coins should be a firm fit because they need to be held in place as the card moves around quickly.
<p>Thanks for the make</p>
<p>Very nice! Performs much better than I expected. A bit of advice: Don't use index cards (I learned that the hard way), and thin cardboard (think cereal box) works quite well.</p>
I adore this!
I was not real impressed.. Until he started consistently hitting that cup from so far away, that was crazy and awesome!! Once I saw that, I was thoroughly impressed, this is about as cool as the iris business card, this even has practical applications (if you define &quot;practical&quot; very loosely)
For the sake of full disclosure I was probably only hitting about 1/3 of the shots out there (or less), and I'm not really sure what all was throwing it off. I think it was largely the wind. In a more controlled environment with smooth concrete floors and no wind I was hitting 80-90%
Well, of course wind is going to throw it off, that has to be expected, however, its still incredibly accurate. I am quite impressed.<br>Most of the applications I can think of are indoors anyway (sinking paperclips in your boss's coffee).
i made one :)
Excellent Project (voted), and well documented too.<br><br>A couple of rules of fun, sorry THUMB!<br><br>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.<br><br>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...
Thanks, I'd like to see some variations and optimization as well.<br><br>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.<br><br>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.<br><br>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 those of us who don't have (assuming!) US pennies, how much should the counterweight weigh, please?
Mine weighs in at about 42 grams.
thanks, dear!
That is great - such a simple concept, yet so efficient!
Thanks Kiteman. I actually did a rough calculation of the mechanical efficiency and came up with 45% which isn't bad considering there are many things that could be done to optimize it's performance (at the cost of being harder to make/use and less durability).<br><br>For comparison the Cardapult V2 launches the same size paper clip about the same distance, but requires about 3x the energy input.
What kind of changes? Altering the curves?
That's one thing that could be looked at, as well as the overall length of the card. If I was going for maximum efficiency the main things I would go for would be moving the counterweight as close to the outside edge as possible (which may also include using a denser counterweight). And minimizing the weight and air resistance of the rest of the device especially as you get more towards the projectile end because it will be moving the fastest on that end. Also a proper sling might help, but it's hard to do on this scale.
You, sir, are awesome! :) Voted!
I am not an old fuddy duddy, but I don't understand the purpose of this item, nor have I ever heard of such a thing, but it was a well presented instructable, so I voted for you. ☺
A trebuchet is an old siege engine that was used to hurl large rocks into castle walls. These days it serves no purpose other than being a fun way to make stuff fly through the air. <br><br>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.<br><br>This is just a scaled down and highly simplified version.<br><br>Thanks for the vote.
Such a great idea! Voted!
Thanks for the vote!
how open .cds and .svg
They are all the same file in different formats, so if you can open the PDF it's the same thing. <br><br>Although svg is probably a bit easier to edit if you need to make changes and works with the free program 'Inkscape'
@Clide; Tweeted! Cheers : ) Site
this is awesome i love all of your clide cards i will be making it today thumbs up good job
Ha! What a great idea!<br>And what a great idea to promote a company.<br><br>I hope you don't mind if I use it to make my own?<br>Thanks a lot, I think this is wonderful.<br><br>I will now have to go and have a look what else you posted. It is always a pleasure to see somebody being creative.
Thnx so much<br><br>I've been waiting so long for another Clide Card, and here one is :)
Super cool man! The distance travelled by the clips amuse me!
these are amazing had so much fun at school playing with them<br>
Wow, once again you amaze me!

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