For this assignment, my team was tasked with designing a bajaj to slide down the cable as fast as possible with the criteria that two ping pong balls be accessible to the outside, yet also secured so as to not fall out upon impact. Due to our final design’s appearance, We named our Bajaj “The Dolphine Helicopter”. Our fairly simplistic first design was created on the first day, while our more complex/showy design was created later as the second prototype.

The first design consisted of two cups taped together in an hourglass shape with their bottoms cut out. The hourglass shape was used to best keep the ping pong balls in. As much weight as we had time for was added to the bottom of the bajaj. Additionally, we created a sort of buffer around the bajaj to better prepare it for impact.

 

Ultimately, the bajaj connection system is what slowed it down the most. Like most of the other designs, we originally had connected it via a paper clip, and the friction between the paper clip and the cable lead to a slow, scooting motion down the cable. When this was switched out for a metallic bag clip, it sped up much quicker.

The second design kept the same spirit as the first, however it consisted of an almost total redo of the first. Instead of cups as the frame, we used a self-made cardboard box. The pointed foam blocks were attached to the nose to add an element of saftey as well as an aerodynamic shape. The ping pong balls were kept inside the “passenger compartment” of the cardboard base. To help it fly straighter (and make it look sexier) we added a tail as well as a fin. The attachment mechanism was redesigned using a PVC connector that was cut down the middle and attached via two strings. This mechanism was supposed to increase surface area so as to better distribute the weight of the device which would prevent cable sagging the poking of the original mechanism on the cable. We also hoped the PVC would be a slicker material than the paper clip.

Our second bajaj did not work as well as expected, however, and about the same as the original at 3-4 seconds per trial. We think the added surface area in the connection might have increased friction. Also the fin and general rotation of the device added drag. We concluded that while a simpler shape and connection mechanism might have given us an edge, it would have cost us something more valuable: style.

This project was definitely exciting. We learned that a simplistic shape combined with a friction-minimizing connector and lots of weight was probably the most efficient method of success.