Hello, recently in science class I had to design a sail which would account for the different forces that my class and I have learnt about. This experiment was to teach us about how designs can affect net force (Net force is the sum of all the forces acting on an object).
Here are the materials I had used for my windracer:
1 Plastic bag
Scissors
Scotch tape
1 Sheet of A4 paper
1 Bag of bamboo skewers (you wont need all of them!)
1 Object with wheels (my teacher supplied this)
Here is the plan for my sail:
Heres how my sail actually turned out:
I had tried to angle the second mast so that the air would run off and push the big sail further. My group considered placing tape around the wheels to get rid of friction, but decided that it get rid of the grip that they had on the ground. We wanted to controll the direction, instead of have it slide around. I wasn’t sure how aerodynamic I could make this design, so I focused on the ‘Bigger sails= More area= More push’ aspect. I likely could have done somthing to the wheels so gain more acceleration from one push.
My group couldn’t create it as we had planned, but the results worked great! We ended up getting second place in the competition.
It traveled well throughout our attempt, I had angled the second mast well and the paper was sturdy enough that wind was consistently pushed into the second sail which was stuck in place, so we had control over the direction. I believe that the wheels were the biggest issue in our wind racer, as I’m sure that most of the friction was caused by them. The net force pushing my wind racer would of been much higher than the resistance.
The variation in the distance my classmates had traveled was relatively similar, with most of them only traveling 2 or 3 meters before stopping. Most of them had used a similar sail design to each other which would of encouraged the wind to pass by either side. The specific sail they used a Bermuda rig sail which is more focused acceleration, in our specific environment it would of discouraged momentum.
If I ever do this again I would use stronger materials to make it less flimsy (it wasn’t as stable as I hoped!), spend the extra time modifying the wheels to get rid of any friction and possibly add a third sail for the extra area. These improvements would be crutial for making a better design, as to my knowledge these were the only areas which I neglected.
The forces acting up on my wind racer during the competeition were push, friction, acceleration and gravity. There was little to no resistance apart from the friction. The net force was unbalanced when racing my project, but it was balanced otherwise. If I had the exact mesurement of how far it went and how quick it was I could calculate the velocity, but I don’t have those numbers.
Feel free to leave any questions or comments below. Have a nice day! : )