Research

• I researched a lot of CO2 dragster cars online. There are a lot of opinions out there on what works best. Some people insist that light, smaller cars have an advantage. Others insist weight doesn't even matter when you reduce friction and focus more on aerodynamics. • Key points to consider: weight of car, length of car, wheel base length

between axles, aerodynamics, reducing friction in axles, skill level required to build.

Design Drawings:I came up with 10 different concepts to be used for a car-some were more practical than others.

I narrowed it down to two car designs that I liked-Both cars had a similar teardrop shape with one having the rear axles hidden under the body while the other having the rear axle exposed.

I wanted a car that was aerodynamic while still keeping weight downSome of these designs were far-fetched: they emphasized one concept of building a car while not accounting for other

aspects.

Prototype

• I narrowed it down to two car designs that I liked-Both cars had a similar teardrop shape with one having the rear axles hidden under the body while the other having the rear axle exposed.

Refine

• I decided to pursue the one with the rear axle exposed of practicality reasons. • I didn't believe that having the rear axle exposed would make it any

less aerodynamic than hiding the wheels and axle underneath the car.• The rear axle hidden would be much harder to cut the hole for the

axle and making the probability of the axle not being exactly straight very high. There would also be a lot more room for error while cutting the hole for the wheels. The Rear axle exposed on both sides would be easier to cut on the saw, thus making less room for error.

Build

• I built the car out of a solid block with a band saw, hole saw, dremel tool, and various sanding papers. • The car has a wheelbase of 19cm with a overall height and width of

6.4 cm by 26cm by 4cm wide.

Test

• Wheel spin results: • Trial 1: FR 1.5s FL 1.5s RR 1.9s RL 1.9s• Trial 2: FR 1.9s FL 1.9s RR 2.5s RL 2.5s• Trial 3:FR 1.4s FL 1.4s RR 3.1s RL3.1s• Inclined Slope Results:• Trial 1: 1cm left• Trial 2: 1cm left• Trial 3: .5cm left

Refine• I changed the structure of the front end of the car when I was

building it. I decided to cut in the front wheel holes so that the wheels would be flush with the body. My thinking was it would be more aerodynamic and shortening the axle space might reduce the overall friction of the axle. I extruded the wheel wells in about 9 mm.