Gravity Vehicle C

[iwonder]

Now there's an interesting ramp... I'd say hot glue, ugly, but effective.

[mrsteven]

Depending on the thickness of the plexiglass, im always a fan of boltint things down. Use washers to evenly distribute the pressure. You might want to counter drill the side with the head so theres less of a profile

[catfoot]

Would anybody be willing to share the general range that they're getting for the optimal height for the vehicle to travel 10 meters? Complications are making it rather difficult to run our own tests and I'd appreciate a general idea of how high I should be building the ramp.

[bearasauras]

30-45cm for 10 meter is what I've heard. You can also do some theoretical calculations and you should get ~32cm as the ideal height assuming no friction.

[catfoot]

45 cm? That seems quite low! (I'm guessing this is because most vehicles use bearings, while my partner and I went low budget and just used metal sleeves). Is it thus safe to assume that, even with higher friction between the axles and the bearings (or sleeves, in our case) that the height would be no greater than 100cm?

[Jdogg]

45 cm? That seems quite low! (I'm guessing this is because most vehicles use bearings, while my partner and I went low budget and just used metal sleeves). Is it thus safe to assume that, even with higher friction between the axles and the bearings (or sleeves, in our case) that the height would be no greater than 100cm?

I would say so...

[Lalaloopsy]

Hey there, I just had an invitational yesterday, scored third with a score of 400.95 behind Stevenson and New Trier. Distance: 8m Time: 7.03 seconds Distance Away: 140mm Height: 38.0 cm. We had tested our vehicle and it had veered left in every single test, so for our first run we shifted the ramp way right. Vehicle ended way right, so we shifted the ramp over the same amount that that was right of the dot. Vehicle still was pretty far right oddly enough. The event supervisor, the coach from New Trier, the best team in Illinois, said that in order to be competitive you had to have a time under 4 seconds. That comment kind of made me confused since obviously we were competitive, yet didn't have a time under 4 seconds. I was kind of shocked at everyone's ramp designs. It seemed as if our ramp was the only one which was in the range of 30-45 cm tall. New Trier was in the 60-70 cm range but their car was like 80 cm long; I'm not entirely sure why they made their car so long though). I didn't see Stevenson's ramp design. Almost all of the other ramp designs were about 1 meter tall, which was peculiar. Possibly all of the other teams just didn't make a new ramp yet.

Just wondering, what other kinds of scores are people receiving?

[iwonder]

We too had an invite yesterday, distance 8m... Funny

Our A team(me) didn't get to do any testing on the new vehicle before contest and scored a 728, just about 500mm away, 62.5cm starting distance and a time of 3.3sec. Our B team got a 350 or so, I don't remember the details exactly, but they were about 200mm from the point and in the low 4's for a time, not sure of the height, but it was a little lower than ours.

With the new height factor I wouldn't worry so much about a raw time score, I'd focus on a time vs height score and say that when your vehicle is in the 60cm range(like ours was, and presumably that proctors team was) you should be able to score in the 3 second range for time.

[XJcwolfyX]

How could you have such a low vehicle but such a fast time? That doesn't seem possible.

[iwonder]

Good bearings, true shafts(straight), low rotational inertia, and a high mass(for the momentum).