Recommendations

         Some of the things that went very well for us during this challenge were ease of operation and the adjustments for angle of release.  Our trebuchet was really easy to operate and it was very consistent and because of this we were able to just concentrate on our accuracy and getting as big a distance as we could.  Our release was also very well built and we could easily adjust it so we could make it release at just the right angle in whatever situation we are in.
         Some recommendations I would make to future builders would be to make sure that your pouch is the right size.  If it is too big then the ball won't release properly and it will just fail.  Also it is important to make sure your trebuchet is very stable and able to withstand repeated uses consistently.  This will make a solid base for you to start altering the performance accurately.

Post-Competition Reflection

During the accuracy part of the competition I think we did fairly well.  Our closest hurl was 1.3m from the center of the ring.  We had some problems with the angle of release when preparing for the challenge after we adjusted the weight but we were able to get it pretty good again by the time the competition started.  If I had a chance to improve our trebuchet I would make sure that the weight was easier to adjust and the base was properly pegged down so it doesn't shake at all.  If we were to build an entirely new trebuchet I would want to make the drop of the counterweight larger as I feel this would greatly improve our distance.  I would do this by shifting the arm on the axle so the side with the counterweight has a greater length.  In order to make our current trebuchet perform better we would need to adjust the angle of release and peg the whole thing down so it doesn't shake.  A cover on the counterweight to hold the weights in would also be good so that they don't fall out after every toss.

Distance Comp Reflections

During the distance part of the competition we were kind of satisfied with our distances.  We were using a cracked ball for most of the competition and believe this may have had an affect on the distance as we used a new ball for the last toss and it went 5m farther than all the other ones.  Our average distance was 37.34 and our farthest was 43 with the new ball mentioned above.  Some changes we will make for the accuracy part of the competition will be to lower the amount of counterweight and adjust the angle of release accordingly so it is still consistent.

Theoretical Range

The theoretical range that we calculated for our trebuchet is 515m (using the formula- range=2(height of drop)(mass of counterweight/mass of payload).  Our actual distance was nowhere near this and came in at an average of only 37.34m with our farthest hurl coming in at 43m.  Some factors that might have kept our trebuchet from performing as well as theory suggests would wind, friction, air resistance, non-perfect angle of release and having a less than perfectly stable base.  The wind was constantly a factor as it was always gusting from different directions as we were shooting.  The friction where our arm rotates in the axle also would have slowed it down as in theory there would not be any friction.  The air resistance on the ball would have slowed it down dramatically and was not accounted for in the theory.  We also had a less than perfect angle of release and unstable base, both of which would take away power that could have otherwise been transmitted to the ball in a perfect flight arc.

Trebuchet Test Day

       I was very happy with test day, though it had a few minor problems, it went very well.  We started off going for the distance part of the challenge and with minimal angle of release adjustments we were able to get an average of 45m consistently.  The pouch worked great and the trigger worked well by releasing the pouch consistently while being a reasonable and safe distance away.

        After the distance trials we did some alterations and started working on the accuracy part of the challenge.  It went ok, but we had problems with the pouch not releasing the ball at these lower speeds.  We were able to fix it a bit but we still haven't completely solved that problem but we will work on that.  When the ball did release we would land about 1.m away from the target that was 15m away every time.  Overall i think it went great but we still need to work on the accuracy part a bit and we have to try to solve the pouch problems.

Trebuchet Post 1

        Some of the main physics principles that applied to our paper trebuchet would be the weight of the projectile and the velocity that the projectile leaves the pouch at.  The higher the velocity and the lower the weight (to a point) the father it will fly.
        There are also many environmental and performance factors that influence how well our trebuchet will perform.  The environmental  factors were greatly minimized on our this trebuchet compared to how it will be on the next one because this one is inside.  The performance factors though that we mainly worked with would be counter weight, angle of release and length of sling.  We adjusted the weight in order to give the projectile more or less velocity.  We used the angle of release to find our most efficient angle which is 45 degrees.  The length of sling affected how the sling let go of the projectile so that we could launch it better.

Egg Drop Challenge Competition Results

Going into the challenge our container weighted about 215.3 grams and had dimensions of 24x23x13.  After a successful full drop of 5m in 0.976sec our egg was in perfect shape and we managed to earn 92.6 egg points, which though is not the best, I was pretty happy with it being our container was so heavy. (photo credit to nic)

Our egg after a successful drop

I think one of the biggest restrictions while building was the size factor.  In order for our container to fly like we wanted it too we had to have a far larger wingspan than we could get inside of the regulations.  This caused us to have to change how our container worked and how we were going to approach the challenge.  I think the most successful part of our design was using the insulation for the padding.  It worked very well and kept the egg unbroken through some of the harder falls that we endured.  It took away a lot of the force and softened the blow considerably.  In order to safely support 2 eggs instead of one I wouldn't change a lot to the design except maybe putting a bit more padding in between the two eggs to keep them from breaking on each other.  Other than that I think it is big enough and the lift on the wings great enough to keep the eggs from breaking.

Egg Drop Challenge Test Day

During test day things went pretty good though not how we expected them to go at all.  We had originally planned on making a sort of airplane to direct the force more forwards vs. down to keep the egg in tact.  When we did our first test though (from 5m) the container just fell straight down and tilted so the wings were useless and the egg was smashed.  After that we gave up on the forward flight and just weighted the front end of the container so it was balanced and it worked by falling perfectly level so the wings could do their work and slow down the container and the egg survived.  All the tests after that one worked out perfectly and consistently and we never broke an egg again. (the video below shows one of those successful tests)