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The Red Streak

Race Order	Entry #	Driver Name	Car Name	Mass (grams)	Length (inches)	Width (inches)	Height (inches)	Distance Traveled (feet)	Running Time (seconds)
22	6	Paul MacNeal	The Red Streak	77	12	10	8	12.25	6.09

Balloon car designer Paul MacNeal writes:

• Design approach taken - explain how it worked.

  I chose to utilize the balloons as a thrust jets out the back end of the car. My idea was to have one balloon speed up the car immediately with the other balloon letting out air at a slower rate to prolong the motion of the vehicle.

• Unique or clever features embodied

  My best feature was the wheels and axle system. The wheels were constructed from thin cardstock. The circles were cutout and then shaped and glued into shallow cones. Two cones were glued edge-to-edge to complete the wheel. The axles were simply straws. I chose to have the wheels fixed to the straws with the axle freely rotating on precision drilled foam board.

  One of my thrust nozzles incorporated an expansion chamber formed by making a conical exit as opposed to a straight cylinder. Not enough testing was performed to verify the value added by this feature.

• Materials of construction (mention unique parts you used or fabricated)

  Axles were plastic straws.
  Wheels were cardboard.
  Body of car was corrugated cardboard, styrofoam cups, and foam board.

• Reasons behind any significant design choices you had to make

  At first, the car body was solid pieces of cardboard. I was able to reduce the weight by 40% by applying the Exacto knife. This dramatically improved the performance.

• Lessons learned (what you'd do differently next time)

  Making everything lighter is a necessity.

MB 1/9/99