Elastic Launched Glider C

jander14indoor
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Re: Elastic Launched Glider C

Post by jander14indoor » May 26th, 2013, 7:48 pm

OK, reminder, the goal of this event is NOT longest flight time but teaching students to take and utilize data. The glider is just a fun non-linear system to use in the exercise, and the time is only one possible measure of how well they've learned to use the data they've gathered and analyzed.

That said, I kind of like the scoring and bonus erikb described. It rewards teams that are more consistent. It rewards a team that uses the data they've gathered on their glider to hit a target time. Requiring more data collection and analysis. That's a good thing given what the authors of this event are trying to get students to learn.

I say kind of only because I want to run some 'what if' scenarios about how that bonus works. Play with the factors, etc.

Couple of questions. Do the students pick which flight is the bonus flight? Do they pick before or after a flight? Only seems to work if before a flight. If a team flys the first four flights and is satisfied, do they get two tries at the bonus? How would that be handled? What kind of strategies might you see the students using to maximize their score?

Thanks,

Jeff Anderson
Livonia, MI

erikb
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Re: Elastic Launched Glider C

Post by erikb » May 27th, 2013, 2:31 am

The bonus would be an elective flight taken within the given flight time and would replace one official flight.

So a team can take 6 official flights and the top 4 are scored or 5 official flights and a bonus where the top 4 flights are scored plus bonus.

The exact time bonus is a single flight attempt. The team may "trim" or practice the exact time flight as part of their block of time. But, only one official attempt may be made.

The competing team would have to announce trim, official or bonus.
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retired1
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Re: Elastic Launched Glider C

Post by retired1 » May 27th, 2013, 5:19 pm

I still do not like the idea of a bonus. Say that you have 5 nearly equal teams and the worst one has a "blind dumb luck bonus flight" and moves to the top of the heap. The skill in this event is building a good glider, flying it well, being skillful enough to miss the overhead obstructions to me is the true measure of this event. A team could have a hundred very similar flights in their gym and not be able to handle the strange effects of the event gym. I will bet more than a cup of coffee that many regionals, some state events and possibly even the nationals will not have the air conditioning off for the entire event. I would guess that flight times would change as the temperature and humidity rise in central Florida next year over the duration of the event.
If the bonus is so important, why not allow a series of trim flights followed by a single bonus flight. With the logic that has been shown so far, the best team is guaranteed to win. If the bonus is large, I would have out teams take a nice safe flight.

musicalcoconut
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Re: Elastic Launched Glider C

Post by musicalcoconut » May 27th, 2013, 5:36 pm

I don't like the idea of a bonus either. I agree with retired1 that there is simply too much luck involved. A team cannot accidentally get a long flight, but they can match a specified time exactly by sheer luck. I understand why people want to make sure teams analyze and use data, but I think the way the event is run currently requires enough data analysis. Teams have to test and make changes to determine exactly which design and launching style produces the best results. To me, adding the bonus time just doesn't seem necessary.
2014 Graduate of Mounds View High School
National Medalist in Elastic Launched Glider (2013) and Dynamic Planet (2014)

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Re: Elastic Launched Glider C

Post by calgoddard » May 27th, 2013, 7:54 pm

A "prediction" bonus based on the difference between an "exact time" and an actual flight time is not a good idea for the reasons eloquently stated above by several other users of this blog.

The user of this blog that outlined a specific prediction bonus formula gives examples for exact time ranges of 8 to 12 seconds for a 20 foot ceiling and 12 to 18 seconds for a 30 foot ceiling.

Such a prediction bonus would have the effect of penalizing teams with superior gliders and rewarding teams with average gliders, i.e. gliders not capable of flights with a 1 foot per second descent rate or better.

Changes to the rules for ELG should not be made which have the effect of a handicap.

The definition of a handicap is "a race or contest in which disadvantages are imposed on contestants of superior ability."

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Re: Elastic Launched Glider C

Post by erikb » May 28th, 2013, 6:07 am

calgoddard wrote:Such a prediction bonus would have the effect of penalizing teams with superior gliders and rewarding teams with average gliders, i.e. gliders not capable of flights with a 1 foot per second descent rate or better.
There is a lot i don't know about gliders, that's why i ask people who do, about a most things. However, I know this statement does not reflect reality in anyway.

The one thing i do know, is what kids with drop rates of 1.2+ can do with their gliders and in no way would a their gliders be at a disadvantage.

Next, I find it far less likely that a team would get a lucky win in such a controlled test. All teams could practice the exact same range of times, over and over, just like in GV. And like GV all teams would have the same opportunity to adjust for the environment. However, unlike GV the variables could be predetermined though math and physics since the science of air density in known. Compared to GV where surface conditions are are complete mystery box.

Next, if the heating and cooling is left on during the event it does boil down to who is the luckiest team no matter what criteria is set. There is no way a team can have just the right glider trimmed and ready to go, for when the air is full blast, barely moving or somewhere in between. Every flight will be different with no consistency no matter what the team does. So this argument that the bonus would be somehow different makes no sense.

Finally, even at a ceiling of 20' a good teams score would be 80 points with a bonus of 10. A really strong team would be in the 96 point range without bonus. So it's not a game changing bonus. It's a reward for hard work that moves a team up or down the ladder to reflect their actual skill not the luck of draw on balsa wood.
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retired1
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Re: Elastic Launched Glider C

Post by retired1 » May 28th, 2013, 7:03 am

erikb wrote:Proposed bonus for gliders

If this bonus is accepted then I will try and talk someone into publishing a paper that will describe all the math needed to predict times taking into account the differences in air density. It appears that it is something that with the right guidance a team can do.
As a retired USAF pilot, I would be very interested in having a copy of that paper.

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Re: Elastic Launched Glider C

Post by erikb » May 28th, 2013, 7:57 am

retired1 wrote:
erikb wrote:Proposed bonus for gliders

If this bonus is accepted then I will try and talk someone into publishing a paper that will describe all the math needed to predict times taking into account the differences in air density. It appears that it is something that with the right guidance a team can do.
As a retired USAF pilot, I would be very interested in having a copy of that paper.
If i can talk someone into writing it, then it will be published for everyone to see.

A direct quote from one the people i asked about this:
"if I were writing the rules I would publish the formulas to be used by all teams for their analysis that is within their knowledge level. 'Use these formulas for your predictions and demonstrate by test data.' Then compare at the finals by demonstration."

Since, this is above what i understand about gliders, (or physics or in general) i went to people who know a lot more about it, then i do. I wanted to make sure it was a fair and reasonable bonus before i put it out there as an option.

Yes, it is all dependent on still air. Just like the scoring is. No matter what anyone does, if the air is not still, then each flight is random, without exception. Yes, heavier gliders will get a slight advantage but they still have to go through random points of air density and movement greatly effecting lift and making each run completely independent of the others. There would be no way to adjust for that. There would be no way of knowing in advance what the best trimming would be for random air.
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wlsguy
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Re: Elastic Launched Glider C

Post by wlsguy » May 28th, 2013, 8:20 am

The bonus you are describing, while possible, seems overly complex. I hate to make the event supervisors think too much.

The current method of adding flight times is easy to understand, rewards the teams who practice, and can be scored with a calculator.
My proposal to reduce the effects of luck and increase use of data is to score 3 of the 5 flights (assuming 2 of the flights may have issues due to room factors, air currents, etc). This requires the students to be more than 50% consistant and doesn't cause the people running the event to be concerned if the flight is "regular" or "bonus".

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Re: Elastic Launched Glider C

Post by erikb » May 28th, 2013, 9:47 am

wlsguy wrote:The bonus you are describing, while possible, seems overly complex. I hate to make the event supervisors think too much.

The current method of adding flight times is easy to understand, rewards the teams who practice, and can be scored with a calculator.
My proposal to reduce the effects of luck and increase use of data is to score 3 of the 5 flights (assuming 2 of the flights may have issues due to room factors, air currents, etc). This requires the students to be more than 50% consistant and doesn't cause the people running the event to be concerned if the flight is "regular" or "bonus".
Keep in mind i am not demanding the bonus be added. Just working out in my own mind and in a public forum, how to make flight logs relevant and not something made up 5 minutes before the contest.

So i am just answering the question: what is a fair and accurate way to measure the data collected on the flight logs? Nothing more then trying to find the best solution for the problem at hand.

However, I do agree that more than 2 flights should be scored.
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