Trebuchet Parts List and Overview

Transcription

1 Trebuchet 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 the sling 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) 2:21:18 PM]

2 Trebuchet Trebuchet after "firing". Parts: 2:21:18 PM]

3 Trebuchet 2:21:18 PM]

4 Trebuchet Throwing Arm 2:21:18 PM]

5 Trebuchet All material is 3/4" softwood. A - main base (1) - 9 cm x 30 cm B - Base Supports (3) cm x 14 cm C - Uprights (2) - 28 cm x 1.8 cm D - braces (2) cm x 27.5 cm (long side, angle 45 degrees) 2:21:18 PM]

6 Trebuchet Trigger block 1.8 cm x 7.5 cm 1.8 cm slot cut in one end. 2:21:18 PM]

7 Trebuchet Return 2:21:18 PM]

8 Construct the counter weight basket Construct the counter-weight basket: 1: Apply white glue to both basket end pieces. 2:21:42 PM]

9 Construct the counter weight basket (Important: one of the end pieces has a slot cut in it to accommodate the arm. Make sure the longest part of the slot is on the outside of the basket.) 2: Align basket bottom piece with end pieces and nail in place with 1" common nails. 2:21:42 PM]

10 Construct the counter weight basket 3: Apply glue to sides of end pieces and attach side plates with 1/2" #6 flat head screws. 2:21:42 PM]

11 Construct the counter weight basket 2:21:42 PM]

12 Construct the counter weight basket Continue to instructions for assembling base. Return 2:21:42 PM]

13 1 Assemble Trebuchet Base 1 - Use white glue and screws to attach main uprights to one of the small base stands. 2:22:30 PM]

14 1 Start with one screw and then make sure the uprights are at 90 degrees (right angle) to the base stand and they 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 of main base. The piece holding the uprights is placed at the distance indicated. (Distance is important). 2:22:30 PM]

15 1 Fasten with 1 1/4" #6 screws and glue. 3 - Attach diagonal braces with 3/4 " #6 screws and glue. 2:22:30 PM]

16 1 5 - attach trigger plate to end of base. Make sure the slot is up and aligned as pictured. 2:22:30 PM]

17 1 Continue to sling assembly instructions. Return 2:22:30 PM]

18 Create the sling 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. 2:22:56 PM]

19 Create the sling 3: Cut a second piece of tape and tape it over the first, capturing the strings. 2:22:56 PM]

20 Create the sling 4: Pull one nail to release the string. 2:22:56 PM]

21 Create the sling 5: Cut two narrow strips of duct tape, use them to shape the duct tape into a pouch. 2:22:56 PM]

22 Create the sling 2:22:56 PM]

23 Create the sling Proceed to Final Assembly Return 2:22:56 PM]

24 Final Assembly Final Assembly 1: 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 of sling. 2:23:23 PM]

25 Final Assembly 3: Pull throwing arm to loaded position. Tape a loop of wire to the back of the pouch so that it protrudes through 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 safe distance. 2:23:23 PM]

26 Final Assembly Proceed to loading your trebuchet. Return 2:23:23 PM]