Solar & astrophysics test engineer Hank Hancock saw a comment on our Mini-Trebuchet post about how to improve the throw distance, and put up his hand to try it out. We sent him a kit, he’ll be building and documenting the before-and-after effects of adding wheels to the design.
His first update is on putting the stock kit together.
Recieved the kit last week and finally was able to get started today, with the help on my daughter, Melissa, and her boyfriend, Sam. Photo shows the kit as it comes out of the box. Since we had the three of us, I had the teenagers remove the pieces while I got started on removing the tabs left over. A simple sanding with an emery board (regular sandpaper will do) made quick work of it.
Once the pieces were loose, the Sam & Melissa began gluing parts together. The entire process probably took all of about one hour.
Even though we followed the directions for making the basket, it did not seem to work as well as I wanted. To help the basket hold the projectile, we added some staples to give it a more “bowl” shape. I think I might find myself a small piece of cloth or leather to make the basket out of, instead of the netting that is provided in the kit.
Looking good, Hank, we can’t wait to see more!
In the Maker Shed
Mini-Trebuchet kit in the Maker Shed
12 thoughts on “Test engineer’s Mini-Trebuchet build”
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Small is nice, but larger is better.
Here at the World Egg Throwing Championships one of our 5 diciplines is the Egg Trebuchet game.
Starting at 30 metres, contenstents, fully protected, are required to hurl an egg to a waiting catcher. At these shorter distances the use of the lob technique is required. As the distance increases the more direct throw is employed, thus the egg is received at a greater speed.
3 attempts at each distance. no points is missed, 1 point if touched and broken, 3 points if caught unbroken. See video and instructions at http://www.eggthrowing.com
Next World Championships is on June 27th.
Once you’ve got the basics working, it might be worth examining why it was called a trebuchet, a “wobbler”. Is there an instability factor which can accelerate the throw rather than boosting the friction losses? The entire operation looks rather more like an atlatl spear thrower to me, where amongst other things the cup bearing stores some of the acceleration energy. Anyone from Franklin Pierce or Vermont here who can advise? They both have teams.
Wheels help when the counterweight is fixed (no hinge).
Won’t help much–if at all–with a hanging counterweight trebuchet. Once the counterweight mass and arm length are fixed, the main variables used in tuning are pin length, pin angle and sling length.
Pardon me–the above should read “Once the counterweight mass and arm length are *eatablished*. . . .”
Dang it! Oughtta say “established”.
Stupid cold fingers. . . .
Just to expand on the wheels question:
The trebuchet shown is a first-order lever. By mounting the central fulcrum on wheels on a horizontal runway, you can change it into a hybrid second-order, with the advantage that more energy goes into the lever arm because the weight can drop vertically, rather than swing in an arc about the fulcrum.