|Entry #||Driver Name||Car Name||Mass
|17||35||Dept. ASIS||Little Balloon That Could||48||10.25||2.25||4.25||13.17||13.35|
Balloon car designer Shirlee Kurtz writes:
Overall design and implementation emphasized philosophy of Faster and Cheaper. Final design was three wheeler powered by balloon air with vectorable exhaust.
Balloon to vectorable exhaust system adapter epoxied for hermeticity and structural integrity. Large wheels chosen to mitigate pavement unevenness. However two large front wheels replaced by one small one after two independent tests on two prototypes the night before indicated smaller wheel helped. Body slimmed down to reduce mass. Vectorable exhaust was implemented with integrated polymeric bellows and tubing system (flexible plastic straw).
Structural composite body was implemented with Styrofoam core and long-chain natural polymer prestressed (rubber band clamped) cellulosic (balsa wood) face sheets for structural integrity and durability. Shrink tube end guides around axles let wheels run freely. Large rear wheels were pre-formed, medium-molecular-weight polyethylene disks ( cream cheese-tub lids) bonded to central plastic bearings (toy car wheels) that ran on polished steel shafts pressed into composite body.
Two large front wheels replaced by one small one after testing consultation (use of pill bottle caps) night before indicated smaller wheel helped performance. Low density materials were critical to reduce mass. Used one balloon after finding it difficult to keep two from interfering with each other or wheels.
Work on improved wheel bearings and wheel roundness. Consider use of water as exhaust ejectant. Reduce mass further.
team design approach by Dept ASIS (Acquisition Support Information Section - Shirlee Kurtz, Francine Fisher, Richard Parker, Carole Bradley, family and friends). It was fun! (P.S. I plan to try it with water in the balloon this weekend.)