Loop score

[SPP SciO]

What's the highest loop score you've seen this season, either in competition or even just prototyping?

My students showed me a video where the conclusion was, the max loop height was going to be 2.7 times smaller than the initial drop height (for a circular loop, not a clothoid). The clothoid loop they were using (Paper roller coaster kit) was ~18cm, they were hoping to try for more with a better track/ball combo, but we aren't even sure if it's worth the height tradeoff.

I'm wondering if loops are undervalued in the scoring, and if the national winners will even have loops. https://docs.google.com/presentation/d/ ... ide=id.p33 The number 50cm was thrown out here as a hypothetical, but I'd be shocked if teams were able to achieve 30+. A 25cm loop is worth 150 points, while a 40cm gap is 160 points, and it seems WAY easier to get the gap than the loop.

[knightmoves]

My students showed me a video where the conclusion was, the max loop height was going to be 2.7 times smaller than the initial drop height (for a circular loop, not a clothoid). The clothoid loop they were using (Paper roller coaster kit) was ~18cm, they were hoping to try for more with a better track/ball combo, but we aren't even sure if it's worth the height tradeoff.

They have misread the video by a factor of 2.

The theoretical limit is a drop height of 2.7 times the loop radius, not the loop diameter.

[knightmoves]

(A comment on the question you mention in passing, of clothoid vs circular loops. I'd have to sit and work out the math to see whether a clothoid loop could theoretically go higher than a circular one, but it feels like it probably can, by a little bit. But the challenge you'll face with a clothoid is that the crossing point of the two tracks (which is where the rules measure the loop height from) isn't at the bottom of the loop. So I'd guess you give up more on height than you gain. )

[Banana2020]

National Winners will DEFINITELY have a loop, the theoretical maximum gap this year is only 65ish cm, that results in a additional score of 260 which is still a great score, however looking at many competitions histograms and from personal experience, teams are into the 600 and even 700 point range even on a 40s time limit, so the loop is ultimately still the way to go... Also the theoretical maximum loop for these dimensions should be in the higher 40cm range...

*edit - ignore anything I said about maximum gap, I wasn't thinking while typing that..., forgot about the jump back

[jasonso123]

I don't see the video link. Can someone please repost the video link mentioned above?

[SPP SciO]

I don't see the video link. Can someone please repost the video link mentioned above?

https://www.youtube.com/watch?v=lsodERSgzrE Here's one, I don't think this is the one my students saw because it's claiming 2.5 vs 2.7, but it's still the radius. So, theoretically, 40+ cm loops are possible. I'm still curious to know what's the max height middle schoolers can achieve in reality. My students have abandoned loops and are trying to max out their gap score instead.

[knightmoves]

I don't see the video link. Can someone please repost the video link mentioned above?

https://www.youtube.com/watch?v=lsodERSgzrE Here's one, I don't think this is the one my students saw because it's claiming 2.5 vs 2.7, but it's still the radius. So, theoretically, 40+ cm loops are possible. I'm still curious to know what's the max height middle schoolers can achieve in reality. My students have abandoned loops and are trying to max out their gap score instead.

2.5 doesn't account for the rotation of the ball. What we have in this event is a ball rolling (probably without slipping) down a track, which means that it has both kinetic energy of its center of mass (0.5 m v^2) and also rotational kinetic energy (0.5 I w^2).