Claytons+Trebuchet


 * CLAYTON'S TREBUCHET PAGE**

A trebuchet is a medieval weapon driven by a counterweight that was used to sling projectiles. The purpose of the trebuchet was to hurl heavy loads, projectiles towards their enemy armies and to breech castle walls during battle. The basic set up a trebuchet includes a frame, an arm, a counterweight, and a sling from which the projectile is released.

1. LEVERS 4.GRAVITATIONAL POTENTIAL ENERGY 7. FRICTION 2.SLINGS 5. KINETIC ENERGY 3. PROJECTILE MOTION 6. NEWTONS LAWS
 * __APPLICABLE PHYSICS PRINCIPLES WITH A TREBUCHET__**

The **lever** concept involves having the force applied at one end and a load at the other with a pivot point in between The closer to pivot point, or fulcrum to the heavier end, where the counterweight is, the farther the projectile can be thrown. Imagine a large weight dropped on one end of a see saw and on the other end is a small object. The large mass will provide quick acceleration to the smaller object. The longer the arm of the trebuchet, the greater the velocity of the projectile. The counterweight is located on the shorter arm with respect to the fulcrum position. As the counterweight is dropped with the short arm, the longer arm travels a greater distance in the same time and therefore the acceleration of the longer arm is higher.

A sling is two strings and a cloth cup to hold the projectile in. As the longer arm swings up quickly it pulls the sling forward in an arc until the sling slips off of the pin on the arm's end. This is known as the **RELEASE ANGLE**. The one end of the sling is still attached to the trebuchet arm. Newtons law that states an object in motion tends to stay in motion is relevant here. The sling stops, but the projectile continues on towards the target. Once the **PROJECTILE** is released the only force acting upon the projectile is **GRAVITY**. The projectile will travel in a parabolic path towards its target. When the projectile is first released it will move against the gravity, but eventually it will fall to the earth due to this same gravity.



When a trebuchet is at the ready to be fired, or loaded stage, the counterweight is raised into a high position. The counterweight has high **GRAVITATIONAL POTENTIAL ENERGY**. This stored energy is released when the trebuchet is fired. The gravitational potential energy of the counterweight is transferred to the projectile, which now is **KINETIC** energy, or energy of motion. A swinging counterweight was used instead of a fixed counterweight. A swinging one is more energy efficient, that is more energy is transferred to the kinetic energy of the arm and projectile.




 * __PROCEDURE USED TO BUILD TREBUCHET__**

1. Researched on internet to find trebuchet plans and designs. 2. Decided on a plan to build that fit into the constraints. 3. Studied plan and wrote a list of materials that would be required. 4. Trip to lumber yard to purchase necessary supplies. 5. Measured and cut pieces to required lengths for trebuchet. 6. Constructed the side braces first. Cut, glued and screwed them together. 7. Constructed the side frames next. Cut, glued and screwed them together. 8. Joined the side frames to the side braces with glued and screws. 9. Constructed the arm of the trebuchet. 10. Drilled hole for 1/4 steel rod in arm, and constructed pivot point for arm. 11. Constructed the counterweight hangers and joined this to arm. 12. Had mom sew string to the denim pouch for the sling. 13. Attached sling to arm and was finished.

1-8ft long 2x4 (spruce) 3-2x2's (spruce) 1-5 pound weight 1-8 ft piece of nylon rope 1-1/4 inch small piece of plywood duct tape numerous #8 1 1/2 inch screws finishing nails 8- 1/4 inch fender washers 8-1/4 inch hex nuts 2-1/4 inch couplings 1-2 inch finishing nail (with head removed) small piece of denim material glue eye screws
 * __LIST OF MATERIALS USED__**.


 * __TREBUCHET PHOTOS__**



Test trials for the trebuchet were conducted in the garage of the Saskatoon Fire Department # 1 Hall. It has a long bay and high roofs to allow the adequate movement of the projecile. The initial tests were conducted without any projectile to make sure the trebuchet firing mechanics were working. Once the trebuchet passed the test, the sling was loaded with the projectile and the results recorded. A small light ball was used as the initial projectile during testing.
 * __PROCEDURE USED TO TEST TREBUCHET__**


 * __TEST TRIAL RESULTS__**


 * TRIAL # || Mass (kg) || L-Arm length (m) || Distance (m) || P=d/mL ||
 * 1 || 4.4 || 1.18 || 1.5 || 0.289 ||
 * 2 || 4.4 || 1.18 || 1.7 || 0.327 ||
 * 3 || 4.4 || 1.18 || 3.0 || 0.327 ||
 * 4 || 4.4 || 1.18 || 3.0 || 0.577 ||
 * 5 || 4.4 || 1.18 || 4.5 || 0.866 ||
 * 6 || 4.4 || 1.18 || 8.0 || 1.54 ||
 * 7 || 4.4 || 1.18 || 9.0 || 1.73 ||
 * 8 || 4.4 || 1.18 || 12.5 || 2.40 ||
 * 9 || 4.4 || 1.18 || 14.6 || 2.81 ||

Trial zero the string became entangled in the release mechanism. There was no release of the projectile. Remeasured the string and it was longer than the throwing arm, The string was cut and released without fail on the next trial. Trial one: The projectile was released, the trebuchet seemed to move as it was released. Seemed that the counterweight was "too heavy" for the trebuchet. Removed one of the weights. Final counterweight was about 2.25 kg. Trial two. Sling seemed to slip as it was pulled through the shoot. Re-examined all knots and release point. Trial three and four. The distance was good, but decided to adjust the release angle of the sling. Thought it was releasing too late and not allowing the projectile to reach maximum height. Trail 5. Better but adjusted release pin one more time. Trial 6. Almost double the previous distance. Adjusted the release pin one more time for next trial. Trial 7. Decided to try a hanging counterweight system. Made the changes and began trials. Trail 8. Best result. Seemed to release at the correct time and good distance.Adjusted release angle just a small bit. Trial 9. Best result.
 * __ANALYSIS OF CHANGES TO IMPROVE EFFICIENCY__**

1. www.stormthecastle.com/trebuchet 2. www.io.com/-beckerdo/other 3,library.thinkquest.org 4.www.medieval-castle.siege.weapon.com
 * __SOURCES__**