Team etc...

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Team members

Jong Hsien Lim

Tad Goff

Wesley Edwards

Tony Blekicki


Brainstorming

Our group discussed several ideas on how to slow the tennis ball down during its fall. We wanted to be creative and effective, so we decided to abandon some of the more creative plans because we feared they would either be hard to build effectively with the given materials or would violate the rules.

===Ideas Discussed===
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A single gore pattern
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Glider

Hot air Balloon

Parachute

  • Use dowels to keep bottom open
  • Cut bag short
  • Use bag material to design original shape

Modifying the ball

  • Spread ball pieces uniformly for balance
  • Flatten ball for increased surface area

We decided to use bag material to design an original shape. In stead of using the shape of the bag we cut it to make a flat sheet of plastic from which we could cut a parachute from scratch.

Construction

Though we had ideas about how the parachute should look, we felt why reinvent the wheel, so we used a design we found online. The design we eventually used is for a model rocket recovery chute (here)
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The six gore pattern we used
This design uses twelve gores. (a gore segment is "a triangular piece of cloth or metal used in three-dimensional fabrication"[1]) We cut the gores out of the plastic by hanging the bag on the wall and projecting a computer image of the gore pattern on it and tracing it with chalk. We then cut the gores out and taped the pieces together to create the parachute shape. we then patched the gap in the top where the pieces met. Finally we created strings to attach the ball by folding pieces of tape longways so that they would stick to themselves. After a bit of adjusting to make sure the parachute was balanced, we were ready to test.

Testing

To test, we dropped our parachute from the top of a fire escape at Mary Lyon (where we we building at the time.) We did find more adjustments were necessary, and after fixing all the bugs, and finding the optimal way to drop the parachute so it would inflate the fastest, we decided we were finished.

Final drop

Although the chute didn't inflate as well as during our tests, our final drop time from the second floor of Hicks was 4.72 seconds (Second place free fall time).