Elastic Launched Glider C

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twototwenty
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Re: Elastic Launched Glider C

Post by twototwenty » November 27th, 2012, 10:55 am

Also don't forget to include what the ceiling height was, or what the maximum height of the flight was if you did it outside; otherwise, a time by itself is pretty useless.

science8
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Re: Elastic Launched Glider C

Post by science8 » November 27th, 2012, 12:49 pm

haha im sorry.
It was 10 seconds and i believe it was 25ft ceiling.

ibetyoudonthave
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Re: Elastic Launched Glider C

Post by ibetyoudonthave » November 27th, 2012, 2:54 pm

This event looks really fun! But I have noooo idea how to build this or test it!!!!!!!!!! CAN SOMEONE PLEASE HELP ME OUT!!!!!!!!!!

Orange714
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Re: Elastic Launched Glider C

Post by Orange714 » November 27th, 2012, 6:07 pm

I'm a little confused. I've read that plans generally suggest that the CG is around 60%-70% away from the LE (Like in a glider with a 5 cm chord, 70% would be 3.5 cm from the LE) However before going for a hard launch, you're supposed to hand glide it. I've added clay to the nose of my model, so it'll do a nice glide. Since I've added clay to the nose the CG has moved forward from the point it was. If I remove clay from the nose I can get the CG to be around where it was, but it no longer glides....Help???

Also is there some wash-in or wash-out that can be added to the glider so that when I go for the first hard launch it won't dive bomb into the ground?

Thanks so much :DD
On a side-note how are you guys doing time-wise with your gliders? And like someone said include units/ceiling height/etc ^.^

Balsa Man
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Re: Elastic Launched Glider C

Post by Balsa Man » November 28th, 2012, 7:33 am

ibetyoudonthave wrote:This event looks really fun! But I have noooo idea how to build this or test it!!!!!!!!!! CAN SOMEONE PLEASE HELP ME OUT!!!!!!!!!!
Uh, you can help yourself out....
Seriously, with all due respect, what do you think might be buried in all the pages of this thread?? Information on how to do this event.
If you go to the first page, and read through, and think about what you read, and follow the numerous great links, I assure you, you will have a very good understanding of how to approach it, and what to do. You may well have, and develop from that study, some specific questions. As you will see, lots of folk have had such questions, and have gotten good answers.
Len Joeris
Fort Collins, CO

science8
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Re: Elastic Launched Glider C

Post by science8 » November 28th, 2012, 11:30 am

Quick question. Would it be worth covering my wooden wings with the carbon tape?

wlsguy
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Re: Elastic Launched Glider C

Post by wlsguy » November 28th, 2012, 11:48 am

science8 wrote:Quick question. Would it be worth covering my wooden wings with the carbon tape?
Why? Are your wings breaking?
If they are breaking because of wing stresses, it may be beneficial to add cabon tape but only in the area required.
If not, the covering will only add weight.

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Re: Elastic Launched Glider C

Post by jander14indoor » November 28th, 2012, 12:48 pm

science8 wrote:Quick question. Would it be worth covering my wooden wings with the carbon tape?
As already mentioned, it depends. Though I can' think of many reasons covering the full wing would be worth the weight hit.

In addition to breaking issues already mentioned, there's another reason to add carbon selectively. That's to stiffen the wing. As you start to get the weights real low (2-3 gm) you may have trouble with the wings flexing too much on launch to control the trim. That's why you see small amounts of carbon fiber along the wings on some of the plans on the AMA site. The carbon is run down the top and bottom of the wing along the approx centerline to act as spars and stiffen the wing more than prevent breakage.

Another comment on reinforcement. The leading edges tend to get dinged as they are very thin. A common trick is to attach a small strip of srpuce or bass (say 1/16 or 1/32 square) to the leading edge before sanding to shape. Then most is sanded away. This leaves a thin strip of harder wood where the balsa would tend to ding most often. You could do the same with a carbon fiber too.

But be careful, a little goes a long way and weight is always your enemy.

Jeff Anderson
Livonia, MI

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Re: Elastic Launched Glider C

Post by illusionist » November 28th, 2012, 2:22 pm

What are approximate fuselage dimensions that have worked well? I'm currently using 3/8 x 1/8 as listed in the simple simon plans, but it's extremely heavy. If I use a thinner piece, I would need to create an external hook for the rubber. What are the best ways to go about doing so? Would something like what was used in wright stuff planes or helicopters be enough for the forces of launch?
2012-2013 Building Event Captain
Rule 7d. "Event Supervisors are allowed to break any competitors' devices" -bearasauras

314chocolate
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Re: Elastic Launched Glider C

Post by 314chocolate » November 28th, 2012, 3:54 pm

Just a thought, is there any reason to scale up a model? If you truely keep everything the same, wouldn't the fight time be the same, but you would just have a bigger glider? It might be an obvious answer, but even if it is, could someone please point it out to me?

Thanks for the info about the carbon fiber!

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