Gravity Vehicle C

[_HenryHscioly_]

ahh...my orchestra teacher has a large bolt cutter.......


Truth s I dunno where to find technology department at my school...i just know we have a tech program..and probably other stuff.. -fail-
i'll ask the robot arm coach at my school(bio chem teacher ) and if no luck, orch. teacher hehe

[olympiaddict]

yeah, you should probably figure that out, it'll only be to your own benefit, and they can help you out lots. They probably have lots of really helpful tools too- check it out.

[mrsteven]

Ya!
I pretty much work exclusively at school in our robotics lab, i dont really have tools at my house, and they have some pretty cool ones at my disposal. After I get my robot built, of course (hehehehe)

[iwonder]

Or there's always a hack saw...

If you don't mind, why such long axles?

[_HenryHscioly_]

Maybe using a siting device? I saw a school use a very wide u-shaped wooden thing. It had a long piece of wood(20cmx5cm), and then on the front and back two pieces of wood(5cmx5cm) perpendicular with holes, and they kinda looked through those holes and did some aligning..
I went to a hardware store and asked for bearings, and they gave me some bearings, $15 for two. is there a way to measure/estimate how good they are...? when I spin the axle+2wheels(rollerblade wheels; 76mm diameter; 100grams each) it'll spin for ~5seconds

[iwonder]

The bearings sound like they'll be fine for this event, but they're not anything spectacular... Sounds like solid reasoning with the longer axles, I was just curious

[joeyjoejoe]

I (oops, I mean my son) just got this event dumped in his lap. We worked all weekend on building a car/ramp. Not a lot of time for the drawing board but it was similar to a middle school event (elastic launch vehicle) he had done so we had a lot of the necessary equipment. I knew from the onset that we needed to lower the launch height. We designed the car with as little friction as possible with what we had laying around since there isn't a lot of time to wait on internet orders this close to the event. We had read on this site that others had made the 10m max distance using heights in the .3-.4 meter range. We took some test runs last night and at .3 meters our car would only make it to the 7.5m mark. To make it the full 10m, we had to raise our ramp (an adjustable brachistocrone-ish beast) to app .45m. We are currently working on eliminating as much friction as possible but have a question (finally!) about the ramp:
Since our car starts at very near vertical (maybe 15 degrees off), aren't we be missing out on the extra potential energy we would get by having the entire car (instead of just the rear) at the launch height by instead launching the car from very near (but not exactly) horizontal?

[Flavorflav]

Whatever you lose in energy you'll more than make up for in time, which is what actually matters in the score. If the car starts nearer to horizontal it will accelerate more slowly, and it will take you a while just to get off the ramp. The solution to the energy problem is simply weight up the back, right over the rear axle.

[EastStroudsburg13]

I (oops, I mean my son) just got this event dumped in his lap. We worked all weekend on building a car/ramp. Not a lot of time for the drawing board but it was similar to a middle school event (elastic launch vehicle) he had done so we had a lot of the necessary equipment. I knew from the onset that we needed to lower the launch height. We designed the car with as little friction as possible with what we had laying around since there isn't a lot of time to wait on internet orders this close to the event. We had read on this site that others had made the 10m max distance using heights in the .3-.4 meter range. We took some test runs last night and at .3 meters our car would only make it to the 7.5m mark. To make it the full 10m, we had to raise our ramp (an adjustable brachistocrone-ish beast) to app .45m. We are currently working on eliminating as much friction as possible but have a question (finally!) about the ramp:
Since our car starts at very near vertical (maybe 15 degrees off), aren't we be missing out on the extra potential energy we would get by having the entire car (instead of just the rear) at the launch height by instead launching the car from very near (but not exactly) horizontal?

Also, try to make sure that your son is doing the majority of the work. You can help with putting things together and making suggestions, but most of the brain work should be done by him Some teams don't like it very much if they find out that parents do most of the building events.

That said, a .45 meter height is not the end of the world. In fact, I think heights of up to .6 are still pretty good, and if you get the vehicle to be very accurate, then you can even go close to .9 and still excel. As long as it's not super super tall and the car is reasonably accurate then you'll be okay!

[lmatkovic3]

If your ramp height is anywhere close to a meter, you'll have a lot of trouble doing well in the event.