trebuchet parts list and overview -...

Trebuchet

http://hila.webcentre.ca/projects/trebuchet/trebuchet_parts.htm[1/4/2011 2:21:18 PM]

Trebuchet

Parts List and Overview

The trebuchet pictured above is armed and ready to throw an object.

Pulling the pin out of the trigger allows the counterweight to fall. The long end of the throwing arm swings up rapidly, pulling thesling forward.

The sling, with an object in its pouch, swings around the end of the throwing arm picking up speed.When the throwing arm rotates past vertical, one end of the sling releases from the slot in the end of the arm.

This releases the object from the pouch allowing it to fly forward.

The physics of this ancient device is complicated involving gravitational potential energy, angular momentum,velocity ratio and kinetic energy.

The Simple Explanation: When the counter-weight falls, its gravitational potential energy is changed to kinetic energy in the moving projectile.

A more detailed discussion of Trebuchet Physics: (Word document)

http://www.carthage.edu/dept/physics/other/trebpaper.doc

Trebuchet


Trebuchet after "firing".

Parts:

Trebuchet


Trebuchet


Throwing Arm

Trebuchet


All material is 3/4" softwood.

A - main base (1) - 9 cm x 30 cm

B - Base Supports (3) - 3.8 cm x 14 cm

C - Uprights (2) - 28 cm x 1.8 cm

D - braces (2) - 1.8 cm x 27.5 cm (long side, angle 45 degrees)

Trebuchet


Trigger block

1.8 cm x 7.5 cm

1.8 cm slot cut in one end.

Trebuchet


Return

http://hila.webcentre.ca/projects/trebuchet/index.htm

Construct the counter weight basket

http://hila.webcentre.ca/projects/trebuchet/basket.htm[1/4/2011 2:21:42 PM]

Construct the counter-weight basket:

1: Apply white glue to both basket end pieces.



(Important: one of the end pieces has a slot cut in it to accommodate the arm. Make sure the longest part ofthe slot is on the outside of the basket.)

2: Align basket bottom piece with end pieces and nail in place with 1" common nails.



3: Apply glue to sides of end pieces and attach side plates with 1/2" #6 flat head screws.



Continue to instructions for assembling base.

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1

http://hila.webcentre.ca/projects/trebuchet/base.htm[1/4/2011 2:22:30 PM]

Assemble Trebuchet Base

1 - Use white glue and screws to attach main uprights to one of the small base stands.

1


Start with one screw and then make sure the uprights are at 90 degrees (right angle) to the base stand andthey align with the outer edge.Tighten both screws.

2 - Set the main base on the three base stands as shown. The two end pieces are aligned with the end ofmain base.

The piece holding the uprights is placed at the distance indicated. (Distance is important).

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Fasten with 1 1/4" #6 screws and glue.

3 - Attach diagonal braces with 3/4 " #6 screws and glue.

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5 - attach trigger plate to end of base. Make sure the slot is up and aligned as pictured.

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Continue to sling assembly instructions.

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Create the sling

http://hila.webcentre.ca/projects/trebuchet/sling.htm[1/4/2011 2:22:56 PM]

Create the sling.

1: Tie string around the 4 nails on the sling template.

2: Cut a 10 cm piece of duct tape, center it sticky-side up under the strings.Press the strings into the tape.

Create the sling


3: Cut a second piece of tape and tape it over the first, capturing the strings.

Create the sling


4: Pull one nail to release the string.

Create the sling


5: Cut two narrow strips of duct tape, use them to shape the duct tape into a pouch.

Create the sling


Create the sling


Proceed to Final Assembly

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Final Assembly

http://hila.webcentre.ca/projects/trebuchet/final_assembly.htm[1/4/2011 2:23:23 PM]

Final Assembly1: Use a loop of wire to attach one end of sling to hole in bottom of throwing arm.

2: Shape a loop of wire so that it easily slides in and out of release slot. Attach this wire to other end ofsling.

Final Assembly


3: Pull throwing arm to loaded position. Tape a loop of wire to the back of the pouch so that it protrudesthrough the slot in the trigger mechanism.

4: Use a straightened paper clip as the trigger pin. Attach a string to it so you can pull from a safedistance.

Final Assembly


Proceed to loading your trebuchet.

Return

http://hila.webcentre.ca/projects/trebuchet/using_your_trebuchet.htm


trebuchet parts list and overview -...

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