Picture of Golf Ball Trebuchet

This is a trebuchet we made for our Concept Physics class. Our trebuchet threw a golf ball a distance of over 29 yards! We were the only all girls group in our class and we built the best trebuchet. We did a little bit of research and set out to construct our own and here is what we created!

Step 1: Materials

7 - 4 ft long 2x4"s
2 - 2 ft long 2x4"s
4 - 3 ft long 2x4"s with the ends cut at 45 degree angles
4 - swivel chair wheels
1 - 2 1/2' re-bar
an eye hook
4 ft of string
a sack
1 laundry detergent basket

The instructions for making this trebuchet were vague and often incorrect. The three-foot long 2x4s are too long and don't fit within the frame on the bottom. The supporting beams in the photo also dont look three foot long. Two and a half-feet or two feet would be more appropriate for the supports. The order for doing things is also really inconvenient. It makes a lot more sense to drill the holes and to add the nail/eye-hook to each end of the arm before attaching the arm to the other two four-foot long 2x4s with the rebar. Also, attach the supporting pieces of wood to the four-foot long 2x4s before attaching them to the base. The string lengths specified are also too short (and also much shorter than the picture shows). Finally, there are no instructions for how to create the sling. We basically made something up and our trebuchet didn't shoot.

meelon181 year ago

Do you have any pictures showing the sack/sling set-up?

Lorddrake3 years ago
In step 2 you state that ..

"The wheels not only help with transportation but also allow more force behind the throw of the trebuchet."

what is the basis for the assumption that the wheels add to the force?

the only way I see that being possible is if you are rolling the trebuchet downhill at the time of launch, and even then the added momentum would be negligible unless it is an insanely steep hill.

It let's it have a little more momentum
ben_k Lorddrake3 years ago
Wheels on the trebuchet let the weight at the end of the arm fall along a straighter path than the arc it would fall along without wheels, which pulls the trebuchet forward at the end of the swing, making it more efficient.
Lorddrake ben_k3 years ago
thanks for the explanation and the visual.
Lazabeam3 years ago
Seriously nice job I'm a freshman in high school I have seen many but yours was the most professional and clean cut
I recently made a trebuchet for a robotics course to chuck a 30lb pumpkin. Using a 150lb trashcan my team only got the pumpkin 12 meters. Of course we made ours out of PVC held together with pneumatic-tubing!
(Oops, it didn't upload)
Robotic's trebuchet.jpg
Your design is the reason for lack of range.
Instead of the smack against the stop bar, you should use a sling on a rail. The sling will give you the extra force and speed. Your system will shortly destroy itself because of the violent stop at the end of the shot. Properly built a trebuchet is a powerful and quiet weapon.

As for Kitman's responses... I don't think he was being overly rude, just frank. He's right, we should not be giving our children a rosy ride. Bullying isn't necessary, but the real world is rough. Your employer or the scientific community will not give you a pass because of your age or handicap. Accuracy counts. There is a lot of jealousy and frankness out there. Also people want their mention if you use their data. Don't ever forget to include your sources.
I think you guys did a great job! Question though... What did you use for a sack, and how large was it? Another thing: How far along the arm did you drill the hole for the rebar?
cheesapuffa5 years ago
This is really cool, I may try it myself
shabaki5 years ago
heh now to buy  some grenades/road flares/beehives/watrer ballons with time release sodium capsules