Reflection on Test day #4

Part 1

In the accuracy part of the challenge project we got off to a super bumy start. The first shot of ours went backwards, along with our second. This left us with one more shot to try and record an accuracy mark, and it came threw when we needed it to with an accuracy marking of 1.60 meters. We were absolutely thrilled with this because this was the best that we had ever gotten it to shoot to 15 meters. Even though this placed us last in our class for rankings, I was just glad that we were relatively close. If we had the chance to modify our current trebuchet design I would want to make our trigger system apparatus alot stronger, because it seemed as though that gave us some troubles. If we were able to start with a brand new modely I would for sure go with a non-fixed weight, just because that seemed to be alot easier to play around with ( viewing from other groups) rather than having to adjust the sling length, arm length and all of that stuff etc. It would also be of interest to me to make a smaller base and therefore add more height onto the trebuchet, for the fact that the taller it is the longer the distance it will shoot. The only thing that I really would've wanted to tweak with on our current model, would've been the pouch. You pretty much need a perfect pouch if you're wanting to get a somewhat consistent shot.

Part 2

From the start of the Trebuchet Challenge I didn't know how keen I would be on doing something like this. The papermodel is where I got extremely frustrated, but I'm glad that we were made to do a mini one, because I think if we just jumped straight into the big design there would be a million questions and alot of anger. In the end I really did enjoy doing such a hands on project. Some of the things that went well for Karissa and I driung the project were:

- the durability of the big model

- our cooperation with eachother

- some different materials that we used rather than the same old thing

 

There's so many things that you could recommend to future classes. But the three main things that I would suggest, would be to have as small as a base as you can so you can have achieve a maximum height. We built ours this way and so did all of my class mates and it seemed to be to our benefit. The second big thing would to have a non-fixed counterweight. It's much more easier to play around with the weight, and then once you feel as though you have your spots you can simply mark down the amounts you used. It's a bit harder using a fixed weight ( what we did) because it was complicating on what we were going to mark in order for us to know our key spots. Lastly I would recommend a very strong and consistent trigger system. You may think that you want to try a complex system, but in reality the easiest ones work just as good!

Reflection on Test day #3

Part 3

To calculate the theoretical range you use the following formula: 2*h* (M/m)
H- stands for the heights that the bucket falls in meters
M- the weight you use (counterweight)
m- the weight of the tennis ball

2*(0.98 m)*(22.6796 kg/ 0.0624 kg) = 712.37 meters
After we got all of our weights and measurements we came up with a theoretical range of 712.
37 meters for our trebuchet. This is obviously a drastic comparison to our average distance that we were shooting of 23.44 meters. There are multiple reasons why I think our trebuchet didn't perform as well as it could've. On our launch day we defintely had murphy there with us! The biggest reason in my mind why it maybe didn't shoot as far would be the angle of release. The nail seemed to be loose and kept wiggling on us, therefore when we went to hammer it in it got slightly changed which can make a big difference. Our arm was another big problem for us. The arm randomly broke off for us after our 3rd throw which meant that in order for us to have an arm we had to shorten it which affected the distance. It was much easier having a fixed weight in the sense that you weren't constantly changing things, but it did make it a bit harder to shoot farther since we couldnt add any weight. I think if we would've added even 25 pounds we wouldve got an extra 10 meters out of it. We saw this in our mini model with the washers, that the more weight you have the farther it seems to go. Another thing that worked in our favour sometimes and other times not was the pouch. I think that if we would've spent more time on that part of the project we wouldn't have had the problem of the ball staying in the pouch or rolling out. Lastly, an even longer length for our pouch strings would've been beneficial, because gravity would've had more time to play its' role of force on it.

Ready to let the trigger system release

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Part 4 

On the day of our trebuchet challenge we began with a 10 minute time frame where we were able to set everything up and make any minor adjustments. After the 10 minutes was up we got 20 minutes to launch 5 times to try and achieve an average of 25 for full marks. Our launches were marked at the following distances:

Launch 1- 20.2 meters

Launch 2- 25.8 meters

Launch 3- 43.6 meters

Launch 4- 0.00 meters

Launch 5- 27.6 meters

After we completed the launches this gave us an average of 23.44 meters. We were happy with all of the distances that our trebuchet shot, other than the 0 meters. The ball not shooting at all made it that much harder for us to try and get a 25 meter average. Overall I was pleased with how it ended up working for us.

The things that we had planned, and did change for the accuracy part of our trebuchet was the arm length, sling length and the angle of release. We shortened both the length of the arm and sling so that there was less time for gravity to effect the ball. The change of the angle of release was almost 60 degrees rather than 45 so that it would shoot higher up rather than farther across. In the end most of our adjustments paid off.

Trebuchet

March 29th was test day for our trebuchet's. We got off to a bit of a shaky start with a few launches going backwards, but after some tweeking we exceeded to shoot on average a distance of 40 meters. This was a big relief for us knowing that we don't have to change anything for our distance. We ran out of time to work with the accuracy part, but plan to do so over the weekend. It's clear since we have a fixed weight that we're going to have to do some major adjusting with our pouch, string length and arm length. We are looking forward to test day and hope to achieve both the accuracy and distance.

Karissa and I with our baby on test day