Gravity Vehicle C

[rayner]

"the dowel must be approximately perpendicular to the floor, extend to within 1.0 cm of the floor and extend at least 20.0 cm above the floor."

Does that mean the dowel itself has to be like 19-20 cm"? That's much larger than dowels have had to be for other vehicle events and seems excessive as a measuring point.

[xiangyu]

"the dowel must be approximately perpendicular to the floor, extend to within 1.0 cm of the floor and extend at least 20.0 cm above the floor."

Does that mean the dowel itself has to be like 19-20 cm"? That's much larger than dowels have had to be for other vehicle events and seems excessive as a measuring point.

Yes. The reason why for the dowel is because in some places the event supervisor uses a photogate system to time your vehicle so your dowel needs to be that height so it triggers the photogate system set in place.

[Things2do]

Hello everyone!

Another question: In order to create the threaded rod braking system, I presume the threaded rod would take the place of the axle in the vehicle. In that case, is it still possible to fit the ball bearings onto the threaded rod? And would all of this work with latex-layered CD wheels?

Thanks!

Yugo

Yes, the threaded rod would replace the axle. You should be able to find threaded rods with the diameter fitting to the bearing, which should work. As for CD's, typically people have adaptors to hook them to the axle. I don't use it so I'm not too familiar with it but I know some people 3d print their own adaptors or buy it somewhere online (Not sure where but others feel free to chime in).

Xiangyu

To add to this, I have brass tubing that slides very snugly onto the threaded rod, allowing you to have a smooth surface for your bearings/wheels/whatever to attach to. You need to make sure that you have enough room for your wingnut to travel if you do this, and make sure that you have your wingnut on before you put the tubing on. As for adapters, I use the ones from Doc Fizzix. Of course, you've gotta have a axle that fits it, but I think he has the size on his listings..

[Fridaychimp]

For those who are flying or traveling long distances to tournaments, how are y'all managing to keep the ramp portable? Is there a method of construction that allows for easy breakdown and reconstruction?

[sciolyperson1]

For those who are flying or traveling long distances to tournaments, how are y'all managing to keep the ramp portable? Is there a method of construction that allows for easy breakdown and reconstruction?

I've heard of teams constructing an extra thin ramp and shorter ramp in order to be able to fit it into the luggage, as well as teams just disassembling it and reassembling it at their hotel. I'd go with the first option.

You could always pay for an oversized baggage though if you don't want to reconstruct a launcher just for that one invy that you're flying to.

[Fridaychimp]

You could always pay for an oversized baggage though if you don't want to reconstruct a launcher just for that one invy that you're flying to.

My goal is to avoid a $200 oversize baggage fee. I United!

[knightmoves]

You could always pay for an oversized baggage though if you don't want to reconstruct a launcher just for that one invy that you're flying to.

My goal is to avoid a $200 oversize baggage fee. I United!

You could build a short ramp that would fit within United's 62 linear inch rule (1 foot wide, 2 feet long, 2 feet high; cut a foam piece to sit on top of the ramp and make a cardboard box to fit. Shipping a ramp packed flat, and screwing it together the night before the competition in the hotel wouldn't be completely impossible. You might want to pack a new ramp kit, screw & glue it the night before, then junk the ramp and fly home without it.

[Crimesolver]

does anyone have any ideas of reducing skidding once the car stops? The has been recently skidding at the very end of my runs, and I would like to know how to solve this problem other than moving the ramp around.

[knightmoves]

does anyone have any ideas of reducing skidding once the car stops? The has been recently skidding at the very end of my runs, and I would like to know how to solve this problem other than moving the ramp around.

Possible ways to reduce skidding:

1. Travel slower (start lower down your ramp). You give up time points.
2. Increase the friction. Try wider, softer wheels.
3. Brake slowly. Have something that slows the axle more gently rather than just locking the wheels.You would be allowed, for example, to have a moving wing nut trigger a spring-loaded brake pad

[MadCow2357]

does anyone have any ideas of reducing skidding once the car stops? The has been recently skidding at the very end of my runs, and I would like to know how to solve this problem other than moving the ramp around.

Is your test surface clean? You probably already do this, but if not it's a good idea to start swiffering the track before runs. Trying to brake efficiently without skidding is very hard when your wheels are on a dusty surface. Pretty sure these effects will be magnified this year as well because of how heavy the vehicles are this year.