Hovercraft B/C

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Ashernoel
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Re: Hovercraft B/C

Postby Ashernoel » May 24th, 2017, 5:27 pm

I know the first place team had a very good time score, but didn't do that well on the test; meanwhile, the 6th place team (us) did well on the test but bombed the time score.
This is not true. And not sure how you would know it since we haven't shared the test scores with anyone to my knowledge.
yea in div C it was similar but more extreme. Bomb time but ace test can get 2nd or 3rd.
Not exactly true either, as there was a range of test/time score combinations across 1st through 6th. Again, I don't think we've shared details with anyone, so not sure where you think you are getting this.
We bombed time and did well on test :(
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Re: Hovercraft B/C

Postby chalker » May 24th, 2017, 6:11 pm

I know the first place team had a very good time score, but didn't do that well on the test; meanwhile, the 6th place team (us) did well on the test but bombed the time score.
This is not true. And not sure how you would know it since we haven't shared the test scores with anyone to my knowledge.
yea in div C it was similar but more extreme. Bomb time but ace test can get 2nd or 3rd.
Not exactly true either, as there was a range of test/time score combinations across 1st through 6th. Again, I don't think we've shared details with anyone, so not sure where you think you are getting this.
We bombed time and did well on test :(
Yes, but 4th / 5th places went the other way (great times, not so great tests). Congrats on third place!

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Re: Hovercraft B/C

Postby Zioly » May 24th, 2017, 6:24 pm


This is not true. And not sure how you would know it since we haven't shared the test scores with anyone to my knowledge.



Not exactly true either, as there was a range of test/time score combinations across 1st through 6th. Again, I don't think we've shared details with anyone, so not sure where you think you are getting this.
We bombed time and did well on test :(
Yes, but 4th / 5th places went the other way (great times, not so great tests). Congrats on third place!
Will you share the medalist scores at one point?
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Re: Hovercraft B/C

Postby UltramatrixMan » May 24th, 2017, 8:28 pm


We bombed time and did well on test :(
Yes, but 4th / 5th places went the other way (great times, not so great tests). Congrats on third place!
Will you share the medalist scores at one point?
Yes please do share some raw scores, I am very intrigued. On the topic of rules changes, I hope that the weight portion of the score is reworked because having a set perfect score (2000 grams), that can be and was achieved (I'm assuming although many incorrect assumptions have already been made here lol) by all the top teams, is not very interesting or exciting. I believe that having a lightest hovercraft wins score next year might be better because A. Nobody will ever achieve a perfect score and B. If you just open up heaviest with no limit, the team that can afford the largest motors wins which is not in the spirit of the competition. That;s just my opinion though :)

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Re: Hovercraft B/C

Postby Ashernoel » May 24th, 2017, 8:31 pm


Yes, but 4th / 5th places went the other way (great times, not so great tests). Congrats on third place!
Will you share the medalist scores at one point?
Yes please do share some raw scores, I am very intrigued. On the topic of rules changes, I hope that the weight portion of the score is reworked because having a set perfect score (2000 grams), that can be and was achieved (I'm assuming although many incorrect assumptions have already been made here lol) by all the top teams, is not very interesting or exciting. I believe that having a lightest hovercraft wins score next year might be better because A. Nobody will ever achieve a perfect score and B. If you just open up heaviest with no limit, the team that can afford the largest motors wins which is not in the spirit of the competition. That;s just my opinion though :)
the mass score is kinda like grade inflation for the teams that prepare the most. Even if they mess up their time score, they should do at least ok because they put in the effort to get a working heavy hovercraft within the rules. I know thermos has similar grade inflation with the plots and stuff, so maybe its just a way to help the top teams out if they have a terrible day and to lower the level of bombing that can really occur.

Also I feel awkward saying our time score points because it was so bad xD but I think we got 50 on test and 24.98 on mass.... maybe something close to 50 on test definitely close who knows
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Re: Hovercraft B/C

Postby UltramatrixMan » May 24th, 2017, 8:39 pm


Will you share the medalist scores at one point?
Yes please do share some raw scores, I am very intrigued. On the topic of rules changes, I hope that the weight portion of the score is reworked because having a set perfect score (2000 grams), that can be and was achieved (I'm assuming although many incorrect assumptions have already been made here lol) by all the top teams, is not very interesting or exciting. I believe that having a lightest hovercraft wins score next year might be better because A. Nobody will ever achieve a perfect score and B. If you just open up heaviest with no limit, the team that can afford the largest motors wins which is not in the spirit of the competition. That;s just my opinion though :)
the mass score is kinda like grade inflation for the teams that prepare the most. Even if they mess up their time score, they should do at least ok because they put in the effort to get a working heavy hovercraft within the rules. I know thermos has similar grade inflation with the plots and stuff, so maybe its just a way to help the top teams out if they have a terrible day and to lower the level of bombing that can really occur.

Also I feel awkward saying our time score points because it was so bad xD but I think we got 50 on test and 24.98 on mass.... maybe something close to 50 on test definitely close who knows
I mean I agree.... but pretty much anybody can just buy a stronger fan and lift the two kilos? *Hint hint* it's been posted in this forum a ways back. Next year I don't think it will come anywhere close to a challenge and definitely not a design challenge to hit two kilos. Getting a very light hovercraft will require some ingenuity and careful building, though.

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Re: Hovercraft B/C

Postby Crtomir » May 25th, 2017, 7:13 am

First off, it does seem like there was a good balance between device score (time and mass) and the test score in determining the overall standings. That, I think, was the intention of the rules. That meant that a team that didn't necessarily have the best device could still be competitive, if they studied harder.

Secondly, if it was so easy to build a hovercraft with close to maximum mass (2kg), why couldn't all the teams do that? The answer is that it is difficult to keep a heavier mass floating on an air cushion and still be able to consistently hit target times. Yes, some teams could just go purchase big huge fans with lots of thrust. Our team did that, but we never needed to use it because the students came up with a better skirt design that was more efficient. So we never adopted the big powerful fan. The smaller fan was sufficient. I feel the skirt was the key to doing well in this event, not having the biggest baddest fan. That's kind of the whole point of a hovercraft versus a helicopter, right? I mean, getting good contained airflow efficiently seems to be a bigger factor than just having the most powerful fan.

That being said, and having run this event at a couple of invitationals in Ohio, it was fun and interesting to see all the different designs the kids came up with from all the different teams. Unlike Towers or Wright Stuff, where pretty much all the best teams settled onto the same design, in Hovercraft, there was no one design that everyone adopted. That make Hovercraft a very exciting event this year.

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Re: Hovercraft B/C

Postby UltramatrixMan » May 25th, 2017, 7:48 am

First off, it does seem like there was a good balance between device score (time and mass) and the test score in determining the overall standings. That, I think, was the intention of the rules. That meant that a team that didn't necessarily have the best device could still be competitive, if they studied harder.

Secondly, if it was so easy to build a hovercraft with close to maximum mass (2kg), why couldn't all the teams do that? The answer is that it is difficult to keep a heavier mass floating on an air cushion and still be able to consistently hit target times. Yes, some teams could just go purchase big huge fans with lots of thrust. Our team did that, but we never needed to use it because the students came up with a better skirt design that was more efficient. So we never adopted the big powerful fan. The smaller fan was sufficient. I feel the skirt was the key to doing well in this event, not having the biggest baddest fan. That's kind of the whole point of a hovercraft versus a helicopter, right? I mean, getting good contained airflow efficiently seems to be a bigger factor than just having the most powerful fan.

That being said, and having run this event at a couple of invitationals in Ohio, it was fun and interesting to see all the different designs the kids came up with from all the different teams. Unlike Towers or Wright Stuff, where pretty much all the best teams settled onto the same design, in Hovercraft, there was no one design that everyone adopted. That make Hovercraft a very exciting event this year.
Is it more difficult to hit target times with a heavier mass vs with a smaller mass? I think that is one of the big questions here. I believe that heavier masses do not make it easier nor harder to hit target times. Opinions?

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Re: Hovercraft B/C

Postby LittyWap » May 25th, 2017, 9:39 am

the skirt was the key to doing well in this event, not having the biggest baddest fan. That's kind of the whole point of a hovercraft versus a helicopter, right? I mean, getting good contained airflow efficiently seems to be a bigger factor than just having the most powerful fan.
Is it more difficult to hit target times with a heavier mass vs with a smaller mass? I think that is one of the big questions here. I believe that heavier masses do not make it easier nor harder to hit target times. Opinions?
Absolutely Crtomir! Skirt design is the most important design aspect of your craft. For us, we kept on ramping up our motors, and the craft's lift improved very little. We stopped working on the vehicle for about 3 weeks to assemble the binder, and having done that, we followed the historic progression of skirt designs, and adopted a variation of the "Momentum Curtain" design. Having done this, our craft lifted 3/8ths of an inch! Of course, once we greatly improved the mass, ours lifted 2/10ths of an inch. Skirt designs are huge! And for that reason, I always showed the proctors my shield in a way that prevented other students from seeing our design.

UltamtrixMan (Hey! a fellow Ben10 fan!), I had both a <100g craft (1st prototype, proof of concept) and a 2000g craft, and for the most part, mass doesn't affect consistency (standard deviation). For both of our crafts, the second/third/fourth runs would be 0.1, 0.2, and 0.3 seconds (respectively) off mark (different from the 0.05 I claimed prior, a change in skirt design and build has reduced consistency, in favor of the ability to sufficiently lift 2000g in order to pass lift test for the hardass proctors), which seems to indicate a lack of a relationship between beefyness of craft and consistency.
Last edited by LittyWap on May 25th, 2017, 2:05 pm, edited 1 time in total.
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Re: Hovercraft B/C

Postby Crtomir » May 25th, 2017, 10:31 am


Is it more difficult to hit target times with a heavier mass vs with a smaller mass? I think that is one of the big questions here. I believe that heavier masses do not make it easier nor harder to hit target times. Opinions?
Good point. If the hovercraft is truly floating on a cushion of air, there shouldn't be a big difference in time accuracy between different masses.

So there were three (mostly) independent factors contributing to the final standings: mass, time, and test. Just because a team had a good mass score did not guarantee a good time score and vice versa. On the other hand, teams that were able to get a good mass score, probably put in the necessary amount of work and practice to get a good time score too.
Last edited by Crtomir on May 26th, 2017, 4:01 am, edited 1 time in total.


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