Difference between revisions of "Build a Trebuchet"

A trebuchet (pronounced TREB-you-shay) is a medieval English siege engine or catapult that consists of a large arm mounted on a cart or stand. In the counterpoise style of trebuchet<ref name="rf1">https://en.wikipedia.org/wiki/Catapult</ref>, a counterweight pulls down the arm, launching a large stone or other projectile from its resting place in the sling opposite the counterweight toward the target, much like David using his sling against goliath <ref name="rf2">http://www.redstoneprojects.com/trebuchetstore/how_a_trebuchet_catapult_works.html</ref> Trebuchets can be built large or small  but all trebuchets, correctly built, illustrate the principle of leverage.

[[Category: Toy Weaponry]]

[[Category: Wooden Sports Equipment]]

#*Whatever you decide you want to launch with your trebuchet, your counterweight should be from 100 to 133 times the weight of your projectile.<ref name="rf3"> http://www.stormthecastle.com/trebuchet/trebuchet-build5.htm</ref> If you want to launch items of various weights, you can set up your trebuchet with a bucket or bag to hold and adjust the counterweight. (If you use a bucket, its weight forms part of the overall counterweight.)

#*One swing arm, or beam.<ref name="rf2" /> This piece should be 1 1/3 times the length of the base pieces; if the base pieces are 1 foot (30 cm) long, the swing arm should be 16 inches (40 cm) long.<ref name="rf4">http://www.stormthecastle.com/trebuchet/how-to-build-a-trebuchet.htm</ref>

#Cut and sand the support braces. The simplest way to make these is from a piece of plywood at least 1/4 inch (6.25 mm) thick. It should be 1/2 the length of either the uprights or the long base pieces. Draw a line from one corner of the square to the other and cut along this line, making a pair of right triangles.<ref name="rf4" />

#Attach the uprights to the long base pieces. Measure 1/4 of the distance from one end of one of the long base pieces, and mark it. Place an end of one of the uprights against this mark and glue it in place, then reinforce the connection with nails or screws. Repeat for the second base piece and upright, using the first as a guide.<ref name="rf4" />

#*For a large trebuchet, you may instead want to cut lengths of planking to serve as braces instead of using plywood sheeting, and either cut the edges at an angle or use two pieces on each side to make a rectangular brace.<ref name="rf5">http://houseplans.glitven.com/trebuchet-building-plans/</ref>

#*The eye hook for the sling will go on the end furthest from where you drilled the holes. It should be open to serve as a release pin,<ref name="rf2" /> allowing one end of the sling to open and allow the swing arm to hurl the projectile forward. To keep the sling from opening too soon, drive a nail into the end, partially covering the release pin. #*Cut the head off the nail to keep the sling from catching.<ref name="rf4" />

#*For a tabletop trebuchet, you may want to attach a piece of posterboard or cardboard to the bottom of the frame to protect the surface the trebuchet rests on when firing it. <ref name="rf4" />

#Mount the swing arm. Place the arm between the uprights with the long end of the arm toward the short end of the frame and the nail over the hook pointing up. Thread the axle through the hole in one of the uprights, then through one of the holes in the swing arm, and finally through the hole in the other upright. <ref name="rf4" />

#*If your trebuchet releases the projectile too soon, the projectile could fly upward or even backward. If it releases too late, the projectile will slam into the ground in front of the trebuchet. You can control the point at which the sling opens and the projectile releases by bending the release pin nail: bend it more if the projectile flies too high and bend it less if the projectile flies too low.<ref name="rf4" />

*If you find the trebuchet’s sling too awkward to bother with, you can replace the sling and its hook with a scoop-shaped bucket. (The bowl on an ice cream scoop would work well for a smaller-sized catapult.) This turns your trebuchet into a mangonel, also called an onager after the wild donkey whose kicking the catapult’s recoil reminded its creators of.<ref name="rf1" />

*If your trebuchet is small enough, you can launch the projectile by sharply pulling down on the short end of the swing arm instead of using a counterweight. This form of trebuchet, a traction trebuchet,<ref name="rf1" /> is similar to how you throw the pelota (ball) in jai alai using a curved cesta, how you launch a spear using an atl-atl, or even how you cast a fishing lure.

*Some trebuchets feature a trough underneath the swing arm to rest the sling on when loading the projectile into it and help guide the projectile during launch.<ref name="rf6">http://www.trebuchet.com/</ref>