trebuchet 1

In term 4, we will be working on producing trebuchet. However, as I am going on exchange, I will be getting a modified assignment for this task. Mr Ward showed us 3 different ways to build the joint. 

1. Butt joint: This is the joint that will not modify very well compare to other methods. PDF glue was spread on the sides of the two sticks and nailed from the horizontal line. This method is not recommended as it assures only small amount of modification

2. rebate joint: There is more space that glues together therefore assure more strong joint. It  was nailed from the side. 

3. reinforced joint: The triangle will be glued and nailed on the side and it will manifest the join very well. This is the recommended method when making trebuchet. 

T3-7

I have constructed a new vehicle because the first one that I made was very slow. The time was around 3.9 seconds. However, the new one was 3.1 seconds which isn't really fast. Mr Ward showed us the draw last week and I was versing with Alina from the first round. I have given up from making a faster car, Alina's car is the fastest vehicle, that's got a new 'world record' (class record). Instead, I earned lots of time I guess. Anyway, I believe I can still make my car go faster by using energizer batteries and putting a elastic band around the wheels. The problem with my vehicle I assume, was that the front part is too light. Because when I roll my car, the front wheel doesn't touch the ground. So even if it's attached to the fishing line, the front will be lifted up, and it can't run to it's fastest speed. 

t3-6: progress on monday the 12th

Kimi wasn't at the lesson because she had math competition and asked me to take a photo of her vehicle. In the lesson, Mr Ward showed us how to sold. Though I learnt it when I was in year 8 and this year, I still couldn't do it. I learnt it again from other girl and now I can do the solding, but still not very confident with it. I have put the switch on the vehicle, not under the body because I don't think it will make much of different. I have cut the wires, and I failed so many times, and I had to get new battery case(?) and the switch. But I then the new switch did not have the wire attached to it, so I had to sold the wires.

Below is the comparison shot of Kimi and my vehicle. The sizes are similar. (we tried to make it same, but really, it can happen) Most of other circumstances are same for our vehicles except the material used for the body and the gear used. I'm assuming that Kimi's car will go faster as she used the lighter material, 

t3-5: different gear used

Mr Ward told us that we should use bigger gear to make our car go faster. I already knew that by observing his past prototypes. However, he did not told us which small ones we should use, he told us to figure out. Kimi have lost her small gear so we have decided to share our gears. So I will use the small one while she do the trial with big one. Then after that, we would swap the gear and see when our vehicles go faster. The reason we are doing this was to see if the big gear would work better on one and not on the other one. I mean small gear could work better on mine and not on Kimi. But still, I predict that small gear is faster than the big gear. Because when I have had a look at Mr Ward and fast girls' cars, no one used big one, but only the small or middle one. I may try on the middle-sized gear too after. The smallest gear have 8 teeth and big one, I think have about 12 teeth. Below is the photo of the gear we used for our vehicles.

The left is photo of my vehicle with small gear and right is Kim's with big gear. We both put the big one on for the wheel. because it was definite that big one is faster than small gear. 

T3-4

Kimi and I have stuck the wheels on to the body. Mr Ward showed our class how to best glue the wheels by sticking a pop stick first, and sand them down, then glue the actual thing on the side of the popstick. This will help glue the wheels parallel, and enhance adhesion so the wheels wouldn't shake very much.

This is the photo of Kimi's car. She put the double-sided to lessen the shaking. 

There are the bottom view of our cars. I did not use the method that Mr Ward showed us on the day because I used MDF board. 

T3-3

This is the second post I put up in this term. Kimi and I has been working together from the start of this project. we have decided to use MDF board and cider..., some new other material that is very light. Because we don't know which will go faster than the other, I will use the MDF board as the body for my car and the other one for Kimi's car. My prediction is that the car with that new material will go faster than mine with MDF board as it will weight lighter. We have decided to use the smallest gear. We were going to experiment them all but we have found out that Mr Ward was using the smallest gear, then we assumed that the smallest gear is the fastest. So with our first cars, our aim is to work out which materials make car go faster than the other. If say, the MDF board one goes faster than the cinder one, Kimi will make the other one with small pieces of cinder attached to the bottom and the top of a pop stick. While she makes a new one, I guess I will change other circumstances of the first cinder one. Like changing the position of the gear or the type of gear, and all the other sorts of stuff that will make the car go faster. When Kimi finishes making her new one, then we will compete that one and the MDF board car that won the last round, compete. Then depending on the results, we may develop our cars from there.

T3-2

I have done some research few days ago, and I have found out that we can make the car go faster by wearing the elastic band on the wheels. (only the back wheels maybe. And Kimi asked about this idea to Mr Ward and he had confirmed with the idea that the elastic band would increase the friction between the wheel and the track so the speed will as well increase. Here are some other keys to make a car go faster:

• Lighter car goes faster/ use the lightest material. 
• Increase the friction between the rear wheels and track
• More mass over the back wheel, the less the rear wheels spin.
• Wheel goes faster without rubber.
• Use double sided tape to stick bearing under the chassis
• Lubrication / oil and grease
• Friction free for all the part touching
• Balance the wheels – sand down the wheels.