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Re: Elastic Launched Glider B

Posted: December 14th, 2019, 9:12 pm
by maxvadas
Also I measured my flap deflection wrong; it was actually 3/8"

Max V

Re: Elastic Launched Glider B

Posted: December 15th, 2019, 4:34 am
by bjt4888
maxvadas wrote:
December 14th, 2019, 9:10 pm
Brian,

Thank you so much for the advice! I tried the shin today and it worked great! I got about 24 seconds in my gym so that was a improvement of 7 seconds. Much appreciated.

Max
Max,

Glad the shim to add wing incidence helped. After adding the 1/100”, you might have needed to add a tiny amount of additional ballast clay to the nose. Sorry, forgot to mention this. But maybe you didn’t need this.

Having flown gliders for many years, once you were able to supply all the glider details, and CG location was noted as 1.5”on a 3” chord wing, I knew that this was the place to start. Flappers in the weight range of SO gliders often need the CG slightly forward of 50%.

You and any others reviewing this forum benefitted from your questions and responses. What we did together was analyze the glider as a system to look for any specification that might be slightly outside of the norm. Knowledge of the “norms”, or best practices, can be attained by any student by doing research. I often recommend to students that they can read all of the current and past forum posts as a good place to start this research.

Good job Max, you officially are a participant in a systems approach to problem solving.

Brian T

Gages to check dimensions

Posted: December 18th, 2019, 2:29 pm
by jander14indoor
With my personal computer back in operation, I've finally been able to update my gages to this years rules and post to Thingiverse.
Here's the ELG one:
https://www.thingiverse.com/thing:4055500
As usual, this works for MY printer, check the end result yourself! I will.

Jeff Anderson
Livonia, MI

Re: Elastic Launched Glider B

Posted: January 8th, 2020, 10:00 am
by xiangyu
Hi everyone, I haven't read through this forum so bear with me if I'm asking questions that has already been answered before.

I have decided to help coach my district's middle school ELG team this year. I don't have much experience in specifically the ELG event but have some experience in the high school Wright Stuff.

What are some basic things I should know to better coach the event? I have read the wiki and knows that data collection will be a vital part of improvement. Speaking of that, is anyone willing to give me a ELG log template or tell me what are some vital elements to keep track of?

Any help is greatly appreciated!!!
Xiangyu

Re: Elastic Launched Glider B

Posted: January 8th, 2020, 10:13 am
by jander14indoor
Start with a SIMPLE proven design. Many conventional AMA designs are close enough to this years rules to copy with minor adjustments.
In trimming the planes, CG and decalage are important. To transition properly, most designs have a 0-0 wing tail angle of attack. Must adjust CG for good glide. If the plan GIVES you a CG and it doesn't fly well (primarily the transition at the top of the launch) there, you probably need to adjust the wing/tail angles of attack.
For data, key elements are angle up and angle of bank on launch, rubber size (though it isn't critical other than as it affects the next) how far rubber band is stretch. Of course height reached, glide time, and observations on behavior like dutch roll, stalls, dives, etc.

There are some VERY good tutorials on YouTube for building and trimming gliders. But be careful, DON'T try to start with the most sophisticated designs. Build a good basic design and learn how to trim and launch for a good transition before you try a 'flapper' design for example.

Jeff Anderson
Livonia, MI

measuring height

Posted: January 9th, 2020, 7:50 am
by akshup
First time SciOly.

How do you measure the peak height of your glider in order to record it in the log book?

Thanks in advance

Re: Elastic Launched Glider B

Posted: January 10th, 2020, 2:53 pm
by jander14indoor
Depends on where you fly. And it us usually an estimate, not an exact number.

If you fly in some place with cement block walls, have someone stand to the side and count how many blocks high the glider flies.

Estimate how high as a rough percentage it gets to room height, say 25%, 50%, 75% etc. Then measure room height and calculate.

Most accurate is to use theodolites. Also most complicated. Basically you need to measure the angular height an object reaches from two locations and the angular offset between the OTHER theodolite and the glider. Then some geometry with the known distance between the theodolites will give you fairly accurate altitude. Google it on line. Can do at low cost equipment wise with a couple of protractors and straws. Commonly done by model rocketry types.

Jeff Anderson
Livonia, MI

Re: Elastic Launched Glider B

Posted: January 10th, 2020, 3:22 pm
by akshup
Thanks a lot!
jander14indoor wrote:
January 10th, 2020, 2:53 pm
Depends on where you fly. And it us usually an estimate, not an exact number.

If you fly in some place with cement block walls, have someone stand to the side and count how many blocks high the glider flies.

Estimate how high as a rough percentage it gets to room height, say 25%, 50%, 75% etc. Then measure room height and calculate.

Most accurate is to use theodolites. Also most complicated. Basically you need to measure the angular height an object reaches from two locations and the angular offset between the OTHER theodolite and the glider. Then some geometry with the known distance between the theodolites will give you fairly accurate altitude. Google it on line. Can do at low cost equipment wise with a couple of protractors and straws. Commonly done by model rocketry types.

Jeff Anderson
Livonia, MI

Re: Elastic Launched Glider B

Posted: January 21st, 2020, 1:16 pm
by PayalParikh
For log book, what does 10 or more test flights mean? Does it mean that we need to make atleast 10 different types of gliders to test? Or, total number of test flights, no matter how many different types of gliders we make.

Please explain us. We are new to this event.

Re: Elastic Launched Glider B

Posted: January 21st, 2020, 8:59 pm
by coachchuckaahs
PayalParikh wrote:
January 21st, 2020, 1:16 pm
For log book, what does 10 or more test flights mean? Does it mean that we need to make atleast 10 different types of gliders to test? Or, total number of test flights, no matter how many different types of gliders we make.

Please explain us. We are new to this event.
At least 10 flights logged. They can all be with the same plane, or different planes. The intent is that you log all adjustable parameters, and you can see what changes were beneficial. So ideally you have many more than 10 flights logged, with the same plane, adjusting 1 variable at a time.

Coach Chuck