Elastic Launched Glider C

[sr243]

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.

Yeah, I think around .4-.6 of the ceiling height is fine so like 8-12 s in a 20 ft gym. That way most top teams would have to calculate and practice to get that time while the middle teams would have to get at least get a good launch. Otherwise 5-10 seconds for regionals, 10-15 for states, and 15+ for nats seems fine to me. I think the bonus shouldn't be enough to make or break a team but push a team that practice a lot and mastered their glider over a team with a slightly better glider without much practice besides enough to get a good time. I think 10 seconds/points is enough. Since most good scores for 2 flights are around 30-60 seconds, 10 seconds is actually quite significant, enough to bump a team up a few spots. I don't think that just getting target time once should outweigh getting 2 very good flights.

So 2 bonus flights of up to 10 points for getting close of the target time sounds fine. Calculation would be easy, 10 - (percent error x 10). Another idea is just to incorporate the target times in the flights themselves so competitors have to choose whether to get closer to the target time or improve on their best time (makes the teams think about their options).

[_HenryHscioly_]

why was there no minimum weight this year?
Past flying events all had minimum mass required, right?
Doesn't that help, in that teams won't have to worry about spending money on buying the best balsa?

[wlsguy]

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.

The extensive use of kits was one of the things I noticed at Nationals.
The Freedom Flight kit was the most popular and the data analysis suggests they do not provide any advantage.
This is probably due to the time required to trim them properly.
Of the 24 teams using them the rankings were everywhere between top 5 and next to last with an equal dispersion throughout.

Analysis of the individual flights also showed some interesting points.
As the number of scored flights increased, the likelyhood of the rankings changing also increased.
This indicates many teams have good repeatable gliders when 2/5 flights are counted but this quickly drops when 4/5 flights are counted.

Since the goal is to have repeatable flights while maintaining maximum performance would it be better to award the win to the team who can make 4- 15 second flights in a row or the team who can make 2- 20 second flights combined with 2- 3 second flights. I would suggest the team with the lower performing but more consistant glider should win. What are everyones else's thoughts?

On the subject of ceiling heights; have teams been seeing this event run in short (less than 20') ceilings? I feel this is rare but have no data to support the opinion.

[chalker7]

why was there no minimum weight this year?
Past flying events all had minimum mass required, right?
Doesn't that help, in that teams won't have to worry about spending money on buying the best balsa?

Because there isn't really a benefit to getting as light as possible in this event. If you go too light, the glider isn't strong enough to be capable of being launched. You can easily reach the minimum effective weight with hobby shop balsa and go well below it by using foam.
In general, we prefer to have the rules be as open as possible and not ban things if there isn't a good reason. Having a minimum mass (in this event) is just a red herring teams would have to deal with and another thing supervisors would have to check.

[erikb]

why was there no minimum weight this year?
Past flying events all had minimum mass required, right?
Doesn't that help, in that teams won't have to worry about spending money on buying the best balsa?

A sheet of 4.5# balsa that makes two 30cm wing span gliders is around $3.50 and easy to come by.
A sheet of under #4 balsa is around $7 and nearly impossible to find.

Yes, between the two the difference is a good glider vs. a great glider in the AMA world. But i would also point out that if you have the skills to work with any balsa that is under #4 you should be allowed to use it. It has little structural integrity and is extremely fragile. Especially if you are going to launch it.

If you look at WIF7 all that carbon tow reinforcement is because the wing would explode on launch without it. This year the kids at poudre got to the point where they understood and could work with 4.2# wood but, there were many heart breaks. 8 hours of sanding wasted because the edge of the sanding block or a fingernail gouged the wing. The first launch the wings exploding or a crash that ends the glider.

My only concern is without a minimum weight their might be too much parent/coach involvement. It's the rarity of the wood not the cost that makes me wonder if a kid was the one that built the wing. You don't get a lot of practice with a very rare wood. But, after thinking about it. There are just a handful of people in america that can work with balsa that light and make a competitive glider. And i think i would be unlikely they would build for a team.

[jander14indoor]

OK, had a chance to digest everyone's posts since last night.

Seems to be two, related, suggestions on how to increase the importance of data collection by integrating a prediction component, similar to other tech events. But, I'm having trouble following the details of the suggestions. Can I request that erikb or sr243 (anyone else is welcome of course) write a proposed paragraph for the rules and then show some examples of how it would work? Maybe how it addresses the criteria I proposed?

Warning, expect nitpicking. PLEASE don't take it personal, I guarantee anything that gets in the rule books will be nitpicked by students and its better to do so beforehand than after the fact. I found it very helpful when I was working on the Robot Arm height task last year, the forum found many holes in my original proposal, some made it into the rules.

Thanks,

Jeff Anderson
Livonia, MI

[erikb]

OK, had a chance to digest everyone's posts since last night.

Seems to be two, related, suggestions on how to increase the importance of data collection by integrating a prediction component, similar to other tech events. But, I'm having trouble following the details of the suggestions. Can I request that erikb or sr243 (anyone else is welcome of course) write a proposed paragraph for the rules and then show some examples of how it would work? Maybe how it addresses the criteria I proposed?

Warning, expect nitpicking. PLEASE don't take it personal, I guarantee anything that gets in the rule books will be nitpicked by students and its better to do so beforehand than after the fact. I found it very helpful when I was working on the Robot Arm height task last year, the forum found many holes in my original proposal, some made it into the rules.

Thanks,

Jeff Anderson
Livonia, MI

Give me a day. I will double check my assumptions with people who actually understand gliders.

Then i will get a proposal together.

[plaid suit guy2]

erikb spoke with me, and i proposed turn radius as something to check because altitude and humidity had little to no effect on this when we made the move to dayton.

[chalker7]

erikb spoke with me, and i proposed turn radius as something to check because altitude and humidity had little to no effect on this when we made the move to dayton.

One critical component of the rules writing process is that we have to ensure every part of the rules are easily enforceable by event supervisors around the country, who are often not experienced. What method would you suggest for them to accurately and quickly check the turning radius of a glider?

[wlsguy]

erikb spoke with me, and i proposed turn radius as something to check because altitude and humidity had little to no effect on this when we made the move to dayton.

The value of multiple data parameters is why more than 3 are required.
Currently suggested are "orbit diameter, cross section of elastic launch loop, height at transition to glide pattern, launch angle, etc"
Once a team is confident they can fly in all gym sizes / spaces, some of these become more constant .

I prefer keeping the primary 3 required for success (height, elastic size, time) and allowing teams to figure out what they find useful.