Anurag+and+Jordan+Trebuchet

= The Lovemaker Trebuchet Wiki=

=Introduction:=

The world's biggest trebuchet, Warwick Castle Trebuchet (London, England), stands 18 meters tall, weighs 22 tonnes, and can throw projectiles like huge flaming rocks up to a height of 30 meters and a distance of 300 meters. Our humble trebuchet may not be able to throw flaming projectiles and compete with Warwick Castle, but standing at almost 1 meter tall and almost just as long, the intimidation factor still lingers. If you want to build a bigg'un follow these instructions. = = =Materials/Tools:=
 * 1 2x2x8 piece of wood
 * 1 2x1x8 piece of wood
 * 1 2x4x8 piece of wood
 * 2 metal hooks
 * Table saw
 * Nails/screws
 * Washers
 * Screw driver
 * Measuring tape
 * Pencil
 * String
 * Cloth
 * Stapler/staples



=Procedure:=
 * Make 2X4 38'' Base 2X2 and 2 38" Side Supports (the perpendicular ones) out of wood
 * Construct 2 more 39'' side supports (the angled ones) out of wood
 * Drill holes at the top of the perpendicular supports to insert metal rod that will hold the throwing arm
 * Drill/screw in support pieces into the base at various measured points
 * Contruct wooden box that will hold the counter weight on the throwing arm (make sure that the box is small enought that it is able to fit inbetween the gap of the the two perpendicular supports)
 * Make 50" throwing arm (cut out a 50" long piece of wood preferably out of the same wood that the angled supports were made out of)
 * Attach wooden counterweight box to throwing arm (drill holes and insert long screw/bolt)
 * Drill another hole in the throwing arm and insert the long bolt between the two perpendicular supports through the throwing arm
 * Trimmed throwing arm a five inches because it was too long
 * Once the throwing arm is attached to the perpendicular supports via the metal bolt along with the counterweight box, drill another hole on the opposite end of the throwing arm (about 3-5 inches in)
 * Insert one end of the string through the hole and tie a sturdy knot around the throwing arm (tie the knot around the side that will be facing the base, or downwards, while in the launching position)
 * Drill another small hole on the face of the throwing arm (the small flat edge that faces outwards)
 * Insert a small eye hook into the small hole (make sure the hook faces away from the base (upwards when in launch posistion)
 * Take a sizeable piece of cloth that will be able to hold your projectile (a chrismtas ornament in this case) and also make sure that it will be able to fit through the gap between the two perpendicular supports holding the throwing arm
 * Make two holes on opposite ends of the cloth (opposite each other on the longer ends)
 * Insert the other end of the string that was tied to the arm of the trebuchet into one of the holes of the cloth and make a knot so that the string is now attached to the trebuchet arm and is holding the cloth on the other end
 * Now take another piece of string and tie one end to the other hole of the cloth
 * Make a loop with the other end of the string so that it can easily be put onto the hook
 * Test the sling by putting the arm in launching position and pretending to launch the sling- make sure that while in the launch position both the strings (extending to the arm- hook and the knot in the hole just below the hook) are tight and there is no slack.
 * If there the string slacks of at all, you will have to tighten it (re-adjust the knots/loop around the hook)
 * Now the trebuchet is ready for testing, just put some weights in the counterweight box and you're set!



=Data Table:=


 * Trial || Mass (kg) || Arm Length (m) || Dist. (m) || P=d/ml ||
 * 1 || 7.8 || 1.5 || 7 || 0.6 ||
 * 2 || 7.8 || 1.5 || 8.5 || 0.73 ||
 * 3 || 7.8 || 1.5 || 10 || 0.85 ||
 * 4 || 7.8 || 1.5 || 11 || 0.94 ||
 * 5 || 7.8 || 1.5 || 8.9 || 0.76 ||
 * 6 || 7.8 || 1.5 || 10 || 0.85 ||
 * 7 || 7.8 || 1.5 || 9.5 || 0.81 ||
 * 8 || 7.8 || 1.5 || 8.5 || 0.73 ||

=Application to Physics:=

The trebuchet covers many of the concepts studied in physics involving motion of some sort. This machine embodies projectile motion more than anything because that is its' primary use. But projectile motion also comes with other types/concepts such as kinematics and of course Newton's Laws.

=

 * Newton's Laws (mostly 2nd):** F=ma can be used to show a projectile being thrown by a trebuchet. This formula partly explains why our ornament ball didn't travel as far as we'd hoped it would. Because the mass was so light, and the force was so great, the acceleration was great...too great. This led the ball to reach its terminal velocity really quickly, which ended up slowing the ball down due to air resistance, and of course gravity.=====


 * Kinematics:** Kinematics is just the study of motion (not including the cause of motion) in general which can also be used to describe a projectile's motion (velocity, time, distance, acceleration etc.).


 * Projectile Motion:** This is common sense in its relation to a trebuchet. By varying certain elements/features on a trebuchet (angle of arm during launch, mass of counterweight, lenght of arm, overall size etc.) you can estimate/control the distance, hang time and overall motion of a projectile. The motion of trebuchet projectiles is no different from the motion of any other projectile, they all travel in variations of parabolic paths. However, the throwing/launching system may not always fully determin a projectile's motion. This is because of factors such as air resistance, gravity and mass of projectile. Since the projectile in this case was an ornament ball, the mass (5g) was extremely light which was influenced quite a bit by friction between the air and its surface (enough to hit terminal velocity quickly when thrown with lots of force). The 45 degree angle allowed the vertical and horizontal velocities to be equal during the moment of release, however once air resistance, gravity and the sheer force that the arm threw at, the ball's horizontal velocity didn't stay constant but rather decreased drastically (because of air friction) along with its vertical velocity being acted upon by gravity at the same time. However, it's overall motion was always the same, a parabolic shape.



=Testing:= During our testing phase we were faced with just one problem- the releasing of the ball. The sling would either relase it to early or to late and therefore throw the ball unconsistantly. Also we noticed that even when the ball was released properly, the ball hit terminal velocity quicker than we thought it would, which also means that we understimated the amount of force that an arm of a large trebuchet can create. =Tweaking the Sling:=

The problem with our sling, as mentioned above, was that it either launched the ball to early or to late on a consistant basis. To fix this we stapled the sling in two places so it formed a pouch. This allowed the ball to be launched consistantly because the ball could only come out of the pouch at a certain angle once in the air, although the release was still a little bit late.

= = =Conclusion:=

In the end, our trebuchet did throw a decent distance of 8-11 meters on a consistant basis after we finished tweaking the sling; however it did not live up to the hype that its' monstrous size demanded. The size, and more so the weight, cancelled out any distance the ornament ball was launched. The sheer power and acceleration at the point of release allowed the ornament ball to hit terminal velocity much quicker than we would have liked. The 45 degree angle of the arm prior to every launch ensured that the ball would travel the most distance possible, but due to the air resistance and the great amount of force given to the ornament ball during the release, it was impossible to increase the distance without decreasing the force the throwing arm threw the ball at. In hindsight, it would have been much more efficient to construct the same trebuchet but a scaled down version of it. The distance the scaled down version would have throw thrown would have more or less matched the original trebuchet's distance but with greater benefits (less mass and arm length). However, we'd like to have another competition with tennis balls only.



The Wikipage was created by Anurag Dalai and the Trebuchet was built by Jordan Li