Elastic Launched Glider C

chalker
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Re: Elastic Launched Glider C

Postby chalker » May 23rd, 2013, 5:18 pm

We are well aware of the flight log issues, unfortunately no one has come up with a reliable, robust and scaleable solution. In my opinion, the flight log is critical simply because it exists.
I never said you weren't
Not to speak for my brother, but I suspect he was alluding to you post in the helicopters thread (http://www.scioly.org/phpBB3/viewtopic. ... 20#p242092)
Here is my problem with Helicopters and gliders. Not enough time is spent doing scientific data collection. And with kits you don't even have to do 10 flights. That can be faked. Build to compete, no middle step.
I also don't think he was trying to imply you thought he wasn't aware of it.....

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wlsguy
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Re: Elastic Launched Glider C

Postby wlsguy » May 23rd, 2013, 6:19 pm

I agree, counting all 5 flights does not allow enough room for mistakes.
On the other hand having a data and repeatability event where success is based on 40% of your attempts doesn't seem right either.

I think teams should need to be successful more than 50% of the time (to reduce winning by luck)
This will also make flight logs even more important since they are the key to repeatability.

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Re: Elastic Launched Glider C

Postby erikb » May 23rd, 2013, 6:58 pm

The exact time flight would be for bonus points. Not the contest. An elective like the raising of the ping pong ball. A completely separate flight from the scoring ones.

A team that is held back because they don't have the a skilled mentor or ability to get the best wood to make the best glider could push into the top of their event with enough practice.

If a team wishes to not put in the time. That is their choice. They don't have to do the bonus.

Next, the differences in time between Colorado and Dayton is .015%. Because thrust is a constant the change in air density is cancelled by the drag difference. It's not the same as wright stuff where thrust is increased and lift is increased. I spoke to several AMA glider guys about this. They all came up with the same conclusion. Gliders basically have the same glide times with a very slight increase in times, in denser air.

To some, that may not make sense because the gliders act so extreme when lift is changed due to air density. But once trimmed it all equals out.

I would argue much it is more consistent than different surfaces for the gravity vehicle event.

In addition, It has been my understanding that bonuses have traditionally been for that team that wants to go the extra mile to win. So i don't understand the rebuttal about all skill levels.

So the formula for figuring scores would be: two best times added together + bonus points.
Bonus is figured as: 10- abs(exact time - flight time)

Also it would not be that hard to figure the bonus times. A good glider drop is one second per foot.
So a good time in a 20 foot ceiling is 20 seconds.
A good bonus time for would be .40 or 8 seconds to .60 or 12

Finally, i believe that if a team were to work towards the bonus they would find that they would also improve their times as they practice and get to understand their glider.
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Re: Elastic Launched Glider C

Postby erikb » May 23rd, 2013, 7:12 pm

I agree, counting all 5 flights does not allow enough room for mistakes.
On the other hand having a data and repeatability event where success is based on 40% of your attempts doesn't seem right either.

I think teams should need to be successful more than 50% of the time (to reduce winning by luck)
This will also make flight logs even more important since they are the key to repeatability.
I would argue that if you are skilled enough to hand launch with the same result each time you are beyond the need of a flight log.

However, your point is that in an event where it's not the best possible outcome in the best possible conditions but the ability to best deal with the obstacles presented at the time of the event makes the AMA scoring style inadequate.

In this case the best 5 of 6 would be a better yard stick to measure by.
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sr243
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Re: Elastic Launched Glider C

Postby sr243 » May 23rd, 2013, 7:13 pm

The difficulty of a target time is that we have vastly different ability levels and physical locations (specifically ceiling sites) across the country. Many teams might not be capable of reaching a 5 second flight time at regional tournaments. If we set one time (or low range of times) for every venue, many locations would not be able to take advantage of their full capabilities while others might not be able to run the event because they can't find a site big enough for the minimum.
I agree that different location would have different ability levels but I think the times I listed are reasonable for anywhere you could realistically test the glider. If a location does not allow for a 15 seconds at states, then the event should be looked into by coordinators. That is a fault of the competition which probably can be avoided by a statement in the rules (state location should have a minimum of 20ft ceiling, regionals 15ft). If the competition doesn't have the minimum, then the competition doesn't really allow the competitors to show what they built in the first place. I would not want to fly my glider in a room of 12 ft nor does it do justice to the competitors who invested so much time.

In addition, if teams cannot reach the minimum requirement, that is fine. This scoring doesn't even tier 2 them for not making the time. I know many mousetrap vehicles which didn't make the minimum distance to be tier 1. Should we lower the distance for that event since it is difficult for people to go the distance? These teams who aren't capable of the minimum are probably the ones who don't even practice enough to make an actual flight log in the first place. In actuality, I hope such targets will give them a goal to aim for like in mousetrap or gravity vehicle.
many locations would not be able to take advantage of their full capabilities while others might not be able to run the event because they can't find a site big enough for the minimum.
I think locations would be able to take advantage of their full capabilities. The score is the best 2 flights times - (absolute difference between target and closest actual). For example, a 40 ft ceiling might have a glider with a score of 25s + 23s - (target of 13s, actual 15s) = 46s. The team got to show their full potential while also getting close to the target score demonstrating practice and mastery with the glider.

Now let's say a site is the minimum 20 ft. Teams cannot reach the target time. The scoring doesn't not harm any team in particular. It is the 3 best times to show reliability of the glider. The score will be 2nd + 3rd best flights - (15 - best flight). An example is 12s +12s - (15s-13s) = 22s.
The exact time flight would be for bonus points. Not the contest. An elective like the raising of the ping pong ball. A completely separate flight from the scoring ones.

A team that is held back because they don't have the a skilled mentor or ability to get the best wood to make the best glider could push into the top of their event with enough practice.

If a team wishes to not put in the time. That is their choice. They don't have to do the bonus.

Next, the differences in time between Colorado and Dayton is .015%. Because thrust is a constant the change in air density is cancelled by the drag difference. It's not the same as wright stuff where thrust is increased and lift is increased. I spoke to several AMA glider guys about this. They all came up with the same conclusion. Gliders basically have the same glide times with a very slight increase in times, in denser air.

To some, that may not make sense because the gliders act so extreme when lift is changed due to air density. But once trimmed it all equals out.

I would argue much it is more consistent than different surfaces for the gravity vehicle event.

In addition, It has been my understanding that bonuses have traditionally been for that team that wants to go the extra mile to win. So i don't understand the rebuttal about all skill levels.

So the formula for figuring scores would be: two best times added together + bonus points.
Bonus is figured as: 10- abs(exact time - flight time)

Also it would not be that hard to figure the bonus times. A good glider drop is one second per foot.
So a good time in a 20 foot ceiling is 20 seconds.
A good bonus time for would be .40 or 8 seconds to .60 or 12

Finally, i believe that if a team were to work towards the bonus they would find that they would also improve their times as they practice and get to understand their glider.
I agree with most of your points. The main difference between your suggestion and mine is whether to make target flight(s) separate. The only benefit about making it separate is so that teams are clearly aiming for best time vs target time. However, the top teams should be clearly aiming for one or the other. I like having the freedom to choose in case the one of target flight wasn't exactly as I wanted. At least 2 flights should be given in case some accident happens (you don't want one unlucky thing ruin your score). Then the issue is time since 2 additional flights would be at least 2 minutes.
Even then, I still think your idea is good and better than a prediction or just using more flights to try to compensate for the log.

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Re: Elastic Launched Glider C

Postby erikb » May 23rd, 2013, 7:14 pm

Also, if you make the bonus time somewhat random that's a lot of data collection. A big flight log. Comparable to a good teams GV log.
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Re: Elastic Launched Glider C

Postby elg4 » May 23rd, 2013, 7:15 pm

Hey guys, I’ve been reading through this thread and I’m not quite sure why everyone is suggesting all of these potential changes. Like what is the issue with the current rules? I agree that the event is based on luck a little more than it should be. However, I do not believe that the current competition rules are based on who builds the lightest glider, or who gets to trim the longest, or who has to travel the shortest distance to arrive at the competition, or who gets the luckiest with their official flights. If teams want to build a risky ultra-light glider, versus a heavier, safer glider with less potential, then go for it! But they should be willing to accept the risks that go along with that, including potential damage.

As for the kits issue, I wholeheartedly disagree with the claim that kits take like 10 trim flights with “no middle step.” My team used a kit, and must have trimmed during our team practices for AT LEAST 10 hours, launching hundreds of flights. To compare, I saw many teams at nationals with our same kit that was getting less than half of our time. Additionally, the kit we used came with parts for four gliders (we constructed all of them), and only one of them showed potential for 15-20 second flights, proving that kits require this “middle step” and an intense amount of trimming.

Finally, my suggestion to make this event more equal and less based on luck is to leave the current rules as they are, but add a testing (as in examination) portion (similar to maglev). The test could be a “what if” scenario test, including questions like “If your glider begins to stall, what are a few adjustments to make in order to fix this problem?” (answers ranging from add mass to the front of the fuselage to decreasing the up elevator on the horizontal stabilizer). The test could also include some of the aviation vocabulary used on threads and websites so often, such as incidence, pitch vs roll vs yaw, and up elevator. This test could also include questions about aerodynamics equations and concepts, such as Bernoulli's principle.

These are just a few suggestions that I have thought of. I really enjoy competing in this event and I hope it can be just as exciting next year as it was this year. Thanks! :)

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Re: Elastic Launched Glider C

Postby erikb » May 23rd, 2013, 7:21 pm

I agree with most of your points. The main difference between your suggestion and mine is whether to make target flight(s) separate. The only benefit about making it separate is so that teams are clearly aiming for best time vs target time. However, the top teams should be clearly aiming for one or the other. I like having the freedom to choose in case the one of target flight wasn't exactly as I wanted. At least 2 flights should be given in case some accident happens (you don't want one unlucky thing ruin your score). Then the issue is time since 2 additional flights would be at least 2 minutes.
Even then, I still think your idea is good and better than a prediction or just using more flights to try to compensate for the log.
The problem i see with one or the other is how low the bar should be for the bonus flights to be a reasonable bonus.

It has to be low enough that any team that works at gliders can achieve.

A great time is a drop of 1.2 seconds per foot. A good time is .9
At our state there were three teams at or above a good time. The most were about .5 to .7

One good flight will outscore one bonus flight by nearly double. Hardly worth the bonus.
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erikb
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Re: Elastic Launched Glider C

Postby erikb » May 23rd, 2013, 7:29 pm

Hey guys, I’ve been reading through this thread and I’m not quite sure why everyone is suggesting all of these potential changes. Like what is the issue with the current rules? I agree that the event is based on luck a little more than it should be. However, I do not believe that the current competition rules are based on who builds the lightest glider, or who gets to trim the longest, or who has to travel the shortest distance to arrive at the competition, or who gets the luckiest with their official flights. If teams want to build a risky ultra-light glider, versus a heavier, safer glider with less potential, then go for it! But they should be willing to accept the risks that go along with that, including potential damage.

As for the kits issue, I wholeheartedly disagree with the claim that kits take like 10 trim flights with “no middle step.” My team used a kit, and must have trimmed during our team practices for AT LEAST 10 hours, launching hundreds of flights. To compare, I saw many teams at nationals with our same kit that was getting less than half of our time. Additionally, the kit we used came with parts for four gliders (we constructed all of them), and only one of them showed potential for 15-20 second flights, proving that kits require this “middle step” and an intense amount of trimming.

Finally, my suggestion to make this event more equal and less based on luck is to leave the current rules as they are, but add a testing (as in examination) portion (similar to maglev). The test could be a “what if” scenario test, including questions like “If your glider begins to stall, what are a few adjustments to make in order to fix this problem?” (answers ranging from add mass to the front of the fuselage to decreasing the up elevator on the horizontal stabilizer). The test could also include some of the aviation vocabulary used on threads and websites so often, such as incidence, pitch vs roll vs yaw, and up elevator. This test could also include questions about aerodynamics equations and concepts, such as Bernoulli's principle.

These are just a few suggestions that I have thought of. I really enjoy competing in this event and I hope it can be just as exciting next year as it was this year. Thanks! :)
Trust me when i say this. My team would love to not have any changes to the rules.

You have already seen one post on here that it is a bad idea.

The discussion is how to get it more congruent with a scientific event where there is data collection and results. Then those results are used to compete.
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jander14indoor
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Re: Elastic Launched Glider C

Postby jander14indoor » May 23rd, 2013, 7:39 pm

Hmm, popular discussion. Several posts since I started typing this. To late to re edit, so I'll post as is. This really belongs about 5 or 6 posts back up the stream. Looks still relevant though.

As the guy (as i remember, it did come from a multi sided conversation on how to get the importance data collection and analysis across without saying it) who first suggested flight logs I'll take a stab.

Good engineers and scientists use test logs because the recognize the critical nature of data. As mentioned already, the goal of this event is to get students to take and effectively use data. And if you look closely that's true of many of the tech and physics rules. So, we added the logs to the rules. Other events took other approaches. We still haven't really figured it out for bridges/tower/boom, but it is just as important there.

Once that was done the problem came in how to reward/punish behavior without making the ES task too difficult. Frankly we liked how easy it was to score the flying events. High time wins. Easy to measure, easy to rank. No fussy calculations. And we really weren't sure how it would work the first few years. Not sure what was important. And we didn't want to coach through the rules. So, we set a minimum requirement to get the idea across and a reasonably low penalty. Again, easy to score.

As chalker7 stated, it has worked pretty well, good teams have good logs and do well on average. Teams without logs seldom do well anyway. Its kind of self penalizing.

Now, we've done it for what, at least 5+ years now. Is it time to get more rigorous based on that experience? Maybe, lets hear suggestions.

But we should also agree on criteria to judge the suggestions before getting too attached to a proposal. When I'm writing rules I like to start with the goal of the rules before I get too far. Otherwise it's easy to get lost in details of an idea and forget why you started the journey. Its also easy, as already demonstrated, to get into unresolvable arguments without realizing you aren't even talking about the same thing!

Here are some I'd suggest:
Keep it simple to score, complicated calculations are subject to errors that only penalize students in the long run.
Keep it relevant to the task of duration.
Frankly, keep the score impact low until it has been proven.
Make sure it rewards the behavior we want to reinforce. What is that behavior?
Keep scoring open ended. Perfect scores just result in ties at nationals and I hated having to resolve a 8 or so way tie in robots last year, thus the height task!
Probably others. Your ideas?

Jeff Anderson
Livonia, MI


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