Murlin Trebuchets Case Studies

Finbarr Saunders
May 13, 2014

Summary:

The Murlin Trebuchet works by a string, attached to a counterweight, is wrapped around the prongs that are attached to the fulcrum. When the weight drops it pulls the prongs and on the last prong is a sling with a projectile.  On part of the sling releases at a certain angle while its rotating around the fulcrum throwing the projectile into the air.  I would like to work on this because its a difficult challenge that will take a lot of effort into the building and designing to make it the most efficient machine possible with the most mechanical advantage.  It's unique because the unlike a normal trebuchet this one drops a counterweight straight down and not using a normal force and resistance arms. These arms are going to be changing within the process of launching the projectile.

Case Study #1

Rating - (7/10)

http://www.instructables.com/id/The-Marshmallow-Trebuchet/#step0

Positives:

1. It has the history of this trebuchet.
2. There are available pictures used in the website.
3. It has ways to improve your design.
4. It has the materials used.

Negatives:

1. No dimensions.
2. Different projectile than what we are using in class and different weight used.

Case Study #2

Rating - (6/10)

http://prezi.com/lpxzueiilmh2/murlin-trebuchet/

Positives:

1. Includes dimensions and sizes to help configure to our preference as a group.
2. Labeled blueprints to help with how to build the trebuchet.
3. Includes useful info withour having to research many sites, the background information

Negatives:

1. Too lengthy and gets annoying for reading it for a long time.

Faster Blog

In the Faster Lab my group of Zach, Morris and I had to use wooden pegs as a faster.  Our design was going for  hovering house or a beach house that's being held up by pegs.  It was a very difficult because it took a while to get all the holes to line up with the right size holes.  While in the process of building the sculpture the group hit a setback when a piece of the wood snapped in two places which then we realized we had to use smaller pegs unless the wood would snap again. So we had to re-drill every hole to fit the newly sized pegs.  Then we had to re-line up the holes and made sure they were the right size in one class period.  The final thing was not the way we had planned it to look like because it had multiple useless holes where we messed up.  It was very difficult to portray a house like that with the limited amount of materials.

Compound Machines

 

After the simple machines were complete we were give the new task of combining the simple machines into one compound machine.  instead of trying for a mechanical advantage of 6 the goal was to obtain the largest mechanical advangtage possible.

We decided to use the pulley, the wheel and axil, and the lever. We were not allowed to use the incline plane. This was the opposite of when we were building the simple machines because we are not going for the AMA of 6. After many tries we were able to come up with a simple idea on how to get a high AMA. We were able to get an AMA of 39 witch mean we got a B+. I wasn’t too worried about the other groups because I really was only competing agents myself to get the best grade I could. But at the same time the way other groups combined their machines intimidated me to do better. Some of the other groups were recording massive amounts of mechanical advantages that completely surpassed our groups' final result.  We had a problem with finding the right place for the pulley to combine with the lever. We fixed this by combining them in different places and testing them to see which placement had the best AMA for is machine. Are methods were not the best but they worked out in the end. We could have spent more time on it rather than talking to other groups and getting distracted.

I learned that you can combine small machines to create one machine that could perform almost 50 times better than just one machine. It was very difficult to decide how we were going to place each machine and combined them for the best AMA. I was surprised to see how easy it was to move the hole machine to lift the wait. WE could take this project and combined it to are trebuchet to make it move quicker and have more accuracy.

Simple Machines

 

 

Wooden Crank, Finbarr, Zach and Ian

 

This project was to challenge us by building 4 simple machines. We built simple machines to a specified mechanical advantage of 6 for the lever, wheel and axil/crank and an inclined plane and a mechanical advantage of 2 for the pulley. This was a challenging project and pushed are mines to the limit.  It was challenging because we had to make marks labeling where to apply force and make it so it could reach the appropriate mechanical advantage.

For the wheel and axle we were tied for 3^rdwith 70% efficiency. For the inclined plane we tied for 3^rd with 36.5% efficiency. With the lever we came in 1^st with 73% efficiency. Lastly for the pulley we came in 4^th with 73% efficiency. It was very difficult to pick a winner due to the disqualification of some of the teams on their machines.

On the wheel and axle we calculated wrong and did not get to the mechanical advantage of 6. Because of this we were rushing to get a new wheel on for the wheel and axle and were slightly off. The same thing happened to are inclined plane that is why we got such low efficacy. We could have fixed these problems by taking more time on the calculations and not on the building itself.

Reducing 6 Simple Machines to 4

1. Screw
2. Pulley
3. Wheel and axle
4. Wedge
5. Lever
6. Inclined Plane

Reducing to 4:
The lever can be mixed into the same category as the inclined plane because a lever is just an inclined plane that as change its slope.  A screw is an inclined planed wrapped around a pole that will holds materials together or lifts something.

Notecard Design Cycle Challenge

In this challenge my group members and I worked with only a notecard and 4 inches of tape.  Using the notecard, we divided it into 8 columns measuring one inch tall and rolled up by hand.  Before the availability of using 45 lb plates there were only books.  Our group totaled at 63 books for a total of 188 lbs.  We didn't stop there we took the time we had a made a total of 6 more tests. One with 12 columns, one with 16 columns, two with 8 columns again and two with 5.  the 12 and 16 columns didn't work as well as the 8 and 5 columns tests.  With the last two tries with the 8 columns we didnt seem to break the record of 188. So we moved to 5 columns and reached a total of 250 lbs.  We were triumphant until another group achieved the goal of 308 lbs.  We pushed for another try.  Staying late one day we kept stacking book after book.
Then, it collapsed.  Calculating each section of books and then the
45 lb plates 293 lbs.  15 lbs short but it was an accomplishment.  The columns were crushed and thats how they failed.  If we were allowed more materials then the goal of 500 lbs would be reachable.

Westwood on the Cutting Edge

The project is using the Emotiv with the 3-D Printer.  This would allow people to set up and create images or sculptures in their mind and have it be made using the 3-D Printer.  This will need the classes of computor science and electricity and electronics to be able to understand how these pieces go together.  Putting these inventions together requires percise wire work and the ability to use creative thinking.







Brainstorming by Finbarr Saunders and Zach Ruiz
1) Use Emotiv and x-ray machine to take x-rays with your mind.
2) Use 3-D Printer to make a life size sculture of someone.
3) Use Emotiv and RaspberryPi to make a computor in your mind.
4) Use Emotiv to instant message someone
5) Use Arduino One to customize personal websites fast and easily