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Turbo Dasher

Race Order	Entry #	Driver Name	Car Name	Mass (grams)	Length (inches)	Width (inches)	Height (inches)	Distance Traveled (feet)	Running Time (seconds)
6	38	Terry Scharton	Turbo Dasher	80	12.5	12	6	22.67	19.74

Balloon car designer Terry Scharton writes:

• Design approach taken - explain how it worked.

  Turbines are a conventional method of taking energy from a jet. However, for a balloon, with 0.37 psi of internal pressure, the pressure ratio (14.7 psi /(14.7 + 0.37) psi = 0.975) and associated jet velocity (~200 ft/sec.) are very small, and a turbine is not very efficient.

• Unique or clever features embodied

  Turbo Dasher featured a direct drive, with the turbine incorporated into the front wheel.

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

  The turbine wheel was fabricated from an empty ribbon dispenser with plastic straw segments used for the turbine blades. The car frame is piano wire soldered together. The jet nozzles are plastic syringes use for feeding small animals.

• Reasons behind any significant design choices you had to make

  I had to add a second jet, in parallel with the first, to get the car to move.

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

  I wouldn't use a turbine -- too inefficient. (See notes on my other entry Turbo Creeper.)

• Anything else you'd like to add

  The calculations on the energy available from a balloon may be of interest to someone. As the calculated energy, 44 ft-lb., seems too high, I would appreciate comments, or corrections, anyone might offer. Email them to Terry Scharton.

MB 1/9/99