the knex trebuchet

This instructable will teach you how to construct a large, almost authentic looking knex trebuchet. This trebuchet can launch marbles about 25 feet with a good launch. I had built this about a year ago, and just took it out of the basement. Loaded it with a marble, pulled the launch pin, and to my surprise, almost broke a window. Later, i loaded it up with airsoft pellets, and launched it at my sisters door. The trebuchet stands about 2 feet, 4 inches tall. It is very simple to construct, and takes about 30 min. The movie should show you a short clip of the trebuchet launching.

-WARNING-

I am not liable for anything stupid you may do with this trebuchet....If you injure or kill anybody with it, don't come crying to me. Just be smart

PS: this is my first instructable, so tell me if it is good, and what improvements i could make to it.

PSS: sorry about the low quality pictures, But you should still be able to get information from them.

UPDATE: i just built a duplicate at my friends house using this instructable...I think i miscounted a few pieces, but if you have your knex bucket near you, this shouldn't be a problem. Also, you may need to tinker with the string length, counterweight weight, and other small stuff...It still works fine though!

Step 1 Materials list

Knex stuff:

(all measurements may not be accurate)

Rods:

Blue x 50
Yellow x 24
Orange/red x 6
Grey x 1

connectors:

Yellow x 9
White x 12
Light Grey x 2
Dark Grey x 2
Red x 18
Blue x !0
Purple x 10

PS: Red can be used in place of orange, and the other way around


Other stuff:

Some sort of tape ( I used scotch tape..the clear stuff...because i was sort of in a pinch...works fine!)
two D cell batteries
String
Scissors
a bit of spare cloth

Comments

[hbartlett1]

cooool!
do u know how to make one with a rector set? im trying to do so now but not finished yet

[knex master 81]

oh yeah second comment

[661rhys]

Hi there. does anyone know what i could use for a weight for a trebuchet that stands about 5ft high? i previously use 1.5 kg of lead, but because i have moved house recently the tebuchet had to be dismantled and the lead has gone missing. please reply if you have any suggestions.

[knex master 81]

if you can find big rocks you could use those

[rawknexstuff]

I made a trebuchet for a school project and it was 12ft tall, and we used about 225 lbs worth of rocks and patio blocks (the patio blocks are about 20 lbs. each) and we broke the school record for distance. So maybe scale that down a bit and you should be good.

[GANSTAMAN4]

well u can use the wheels for a counter weight. i used them once and they work rather well. also you could try to use same smaller batteries.

[pindalanderz]

save up your money and buy 1.5 kg of silver. that way you have a good investment worth about 960 USD right now ( about 500 british pounds) that you can use as a weight for your trebuchet.

[-insertnamehere-]

good idea, lol

[girrandminimoose4life]

Me and my friend built one a couple years ago ours wasnt as big as yours but it was close. To get a tennis ball to go a meter we used a brick.

[sam and the beanstalk]

hi

[ElvenChild]

hi

[stopanator]

i made and it it so cool! i cut my old 3 year old shirt dident fit my mom almost threw out but i took it i used a rock for weight

[13remco13]

it looks good! I have a question:is there an alternative for the counterweight and the piece of cloth?

[GANSTAMAN4]

u can use smaller batteries for the weight, but u need cloth for the sling

[Darbysboy1]

flio191 you dope it says that you need 50 blues!!!

[-insertnamehere-]

I have already corrected that

[Darbysboy1]

ok i hadn't realized that

[Darbysboy1]

i had a lot of trouble with your trebuchet because when i would fire it would just swing the cloth cause the marble fell out right behind the thing

[Darbysboy1]

so i decided to mod it to prevent that from happening (but i think i got a "little" carried away because i ended up with a prototype of a catapult) now i guess the problem can't be mine unless i rebuild the trebuchet. ehehehehe :D please tell me should i post it (here's some pics)

[GANSTAMAN4]

isn't it more of a catapault?

[matrix828]

post it!!

[zuulthedestroyer]

make it again and post it!!!!

[da best]

i built it from your pics its good +1

[zuulthedestroyer]

can u post it den?

[-insertnamehere-]

lol! that's awesome! how far does it launch? Yours looks really cool :) If you do post it ( I hope you do) I will definitely build it. It looks like you are using rubber bands for propulsion, am I right?

[Darbysboy1]

i need either more rubber bands, newer ones, or the wide, blue ones like you find in the store. because im using rubber bands that i just find on the ground, theyre not in very good condition. right now it only shoots about 2 1/2 feet.

[snipeyouout]

my prototype trebuchetshoots about 10 feet

[GANSTAMAN4]

wow dude that's so cool

[shmuki]

that looks awesome! put it on so i can build it plz.

[Darbysboy1]

sorry dude, thats a negative. I would post it but two hours after I posted my last comment, I put too many rubber bands on it and it broke. oh sorry, I meant that there were pieces flying everywhere!!!!!!!! I just gave up.

[erikos kostarikos]

i like it very much. i thought about it to make a trebuchet 2, but i dindnt know how. thanks for the ideas

[vandeegraaffsrock!!]

this sucks balls it does not work at all it sucks

[stormz76]

i put 2 d's and 2 c's and a rubberband on the arm doubled it up and it works great. i couldnt get it to work but then i put 1 marble in and it went a good 20 feet

[CHRISTYTWISTY]

hey how many blues u need 4 dis ps looks great dooo

[duker]

I think you should post it.

[Ltcheesecracker]

it is posted nooblet

[duker]

I think it is a great idea!!!!!!!!!!!!!!!!!!!1

[duker]

I think it is a great idea!!!!!!!!!!!!!!!!!!!!!!!!

[Yang46]

can you make a mini version of the catapult you posted?

[smidge147]

check out this beast!!!!
http://www.instructables.com/community/knex-trebuchet/