Launch It: the Paper Catapult.

Give all your classmates or co-workers copies of the template - declare war over lunchtime...

Step 1: Materials and Tools

This is a cut-out-and-make Instructable.

You need a copy of the template (I work to A4), a cocktail stick, scissors and a glue-stick to make each catapult (though sticky tape may be useful for battle-field repairs). A cutting mat is a lot of help if your work bench is a s rough as mine (my mat is marked in 1cm squares, which gives you an idea of the sheer size of this great weapon).

New for 2009, at no extra cost! A redrawn PDF file of the template is now attached to this step!

The ammunition can be anything that will fit in the catapult's bucket - paper balls, the rubbers off pencils. I shot Tic Tacs at my class - if they caught them before they hit the floor, they ate them.

Safety

A pad of paper towel or modelling clay will stop you skewering yourself when you poke the necessary holes in the paper.

Full personal safety precautions can be seen in the video in step five.

Step 2: The Throwing Arm.

We'll do the hardest single piece first.

The throwing arm has two ends (doh!), which both need folding properly to make it work.

1. Cut out the arm (cut all solid lines, score all dotted lines), and use the cocktail stick to pierce holes at the dots.

2. Fold the whole thing into a square-section beam. Glue the full length of the flap and allow to dry. You will be able to tell which way up the beam goes by looking at the writing down the sides.

3. At the "flippy end", fold the two narrow flaps over and glue their outsides. Fold the long central flap over the narrow flaps and pinch gently along the corners to make it stick. Glue under the end of the long flap to stick to the underside of the arm.

4. At the bucket end of the arm, there is a flap connected to the top surface of the beam. Glue under the end of the flap, and press it down into the beam - it should stick to the inside of the lower face of the beam, and block off the end of the beam at the same time, preventing ammunition slipping down inside the arm, which would be inconvenient.

5. Glue the outside face of the two side flaps and fold them over to make the back / end of the bucket. You should have one flap left - lift it up and stick to the outer side of the two flaps you just glued.

The arm is done. Set it aside for now.

Step 3: The Base.

Rather than create a base in five parts, I have chosen to design it in one piece. This makes the corners more rigid, and reduces the number of pieces lost when you sneeze at just the wrong time.

Cut and crease the template, then start at the long sides - the sides fold up, inwards, down and then towards the centre of the frame. Glue the last pasrt down to the base of the frame.

When you have glued both sides, work on the ends. The first fold up seems to leave two extra bits sticking out at the sides. They're supposed to be there - glue them to the outside of the sides of the base. As you fold it over the top, glue the end down onto the sides of the base.

Two longer flaps glue to the tops of the side beams.

The ends then fold down inside the same way as the long sides. Glue them down, and then set the base aside to dry.

Step 4: The Frame.

The frame that supports the arm has four beams - two vertical and two diagonal.

The Vertical Beams

Cut and crease - note that the flaps at one end of the beam do not all get creased.

Glue the long flap and fold the piece into a square-section beam. Make sure the three holes line up (you should have just glued one hole over another).

Pierce holes at the three dots, then glue the outside of three of the flaps at the end with the dots. Fold the three glued flaps on top of each other, then cover the third glued flap with the fourth, dry flap.

At the other (lower) end of the beam, glue one of the creased flaps, fold it down, and fold the opposite flap on top of it.

You should now have a beam with two flaps sticking out at one end.

Repeat with the other beam.

The Diagonal Beams

Cut and crease.

Glue the long(ish) flap, and fold the piece into a square-section beam. You should have six loose, unglued flaps.

Repeat with the other diagonal beam.

Step 5: Construction.

Time to put the whole thing together.

Lay the base on your workspace, "beams up".

Take one vertical beam, and glue the insides of the loose flaps. Stand it near one end of the base, with the flaps astride the beam (see photo). Press the flaps into place for a few seconds, then repeat with the other vertical beam. Before the glue has a chance to dry properly, thread the cocktail stick through the holes you pierced yo make sure they are all in line (you should be able to slide the second beam a little bit if you need to, before the glue dries).

Take one of the diagonal beams and glue the insides of all six flaps. Set it against the side of one of the vertical beams, with the four narrower flaps astride the vertical beam and the beam of the base. The end flaps should be pressed into place against the vertical beam and the base beam.

Repeat with the other diagonal beam on the other vertical beam.

Hold the firing arm between the tops of the two vertical beams (make sure it's the right way up!) and thread the cocktail stick back through the whole lot - both vertical beams and the arm.

You need to give the joints a little time to set again, but otherwise you're finished.

Load up the bucket with the ammunition of your choice, and LOOSE!

Step 6: Template.

If you're not a "pro account" holder, you won't have actually seen the template yet.

Here it is - enjoy.

Comments

[physicsteach]

For high school students, about how long do you think it would take them to make?

[Kiteman]

It depends greatly on both their dexterity and how well they follow instructions - anywhere from 20 minutes to an hour, but typically around 30-40 minutes.

[ubendelgado]

@ubendelgado

patato

[T.K. Chumper]

this is awesome!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

[Kiteman]

Thank you.

[chubawabu]

Another amazing instructable by Kiteman, well done.

[smpash]

by cocktail stick you mean tooth pick right?

[Kiteman]

No, I mean cocktail stick.

It's the sort of thing they stick olives on in drinks. In the UK, they're sold in boxes of a hundred for a few pennies at supermarkets.

However, if you have a toothpick, and it's long enough, by all means use it.

[smpash]

well in the us they are the same thing thanks though

[JimKelleher]

This is a great project. However, my son and I soon tired of of launching bits of crumpled paper at each other. That's when I realized the bucket was the perfect size for a 'kibble' (nugget of dried dog food). The kibble was such a great projectile that we needed to change our launching position so that we could fire down the hallway. Needless to say, Molly (the family dog) loves this project the most.

A couple of comments about my build. Here in the US I printed it out at 95% onto card stock, 35 lb paper instead of 20 lb copier paper.
I 'score' my crease lines with a single heavy pass with a ball point pen and a steel ruler as a guide.
I rough cut the pieces with a pair of scissors and finished them off with a sharp utility knife, steel ruler and a plastic cutting board.
I used a white school glue applied to the tabs with a small paint brush.
I folded most of the creases with the lines inside to make a cleaner model. Except for the throwing arm, needed the Instructables.com writing on the outside.

Cheers,
Jim

[Kiteman]

That sounds excellent, practically engineering!

[reddevved]

I don't know why but I can see the pdf template and I am not a Pro Member. Could be a glitch or I am just that awesome(like you).

[Kiteman]

No, it's because I uploaded the PDF as if it was an image, specifically so that non-pro members can get at it.

It's the PDF of the full project that is restricted to pro members.

[reddevved]

Oh I thought I was just glitched.

[sgriffin4]

I can't download the PDF because I'm not a registered member :/

[Kiteman]

If you look at the last step, I attached the template as if it were an image - click where it says "Catapult template.pdf", and you can download it just fine.

[TheKnotTier]

https://www.instructables.com/id/simple-toilet-paper-roll-penny-gun-powerful/

[a_person]

for astetic reasons one of the instructables logos is backwards on the throwing arm

[lunius]

I noticed that too... It bugged me throughout the building process...

Kiteman, I'm going to put a mod on my catapult and perhaps make an 'ible for it, but I will point out that it is merely a mod, and that your genius is the cause for this amazing work of art :D

[Houdinipeter]

Being on instructables for a few years now, I have looked at this project so many times. But never got around to making one for myself.

Today my physics teacher took the suggestion of making these in class. He had the whole class making their own catapult so we could learn more about projectiles.

Thank you so much Kiteman! and thank you instructables!