Future Aviation Events

retired1
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Re: Future Aviation Events

Post by retired1 »

Look at the glue joint on the wings. I suspect that you will find tiny slivers of the fuselage there. A remote possibility is it is the wing grain pulling out. If you look at the fuselage, you might find the slivers there. This is because gel does not penetrate into the balsa deep enough and you are only gluing the outer ring of the balsa grain and it is failing. I have seen this on towers. I would make a new fuselage and rotate it 90 degrees from the way you made the two. An alternative is to go to a thinner CA glue. Ambroid or Duco airplane glue might work better, but take a full day to cure.
Which model are you building?
If that does not work, add a bead of glue on both sides of the fuselage at the wing joint. You might try adding a doubler of say 1/16 balsa at that joint. I do not care for this idea as it adds weight, but will strengthen the joint.
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Re: Future Aviation Events

Post by twototwenty »

Also, make sure that it is the glue joint...that it isn't the wings hitting the launch handle. I know this seems unlikely, but it has happened to me once or twice when I was launching with poor technique.
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Re: Future Aviation Events

Post by _HenryHscioly_ »

how does duco and ambroid glues work?
is this similar?

http://www.walmart.com/ip/Henkel-NB-Mul ... escription
The walmart near me has a lot of these, and they are only $1 each.
It is translucent and the glue becomes gel-like really soon after i squeeze out.

Would wood glue work? It seems kinda thin and not viscous.
I tried to laminate 3 long pieces with wood glue this summer, and it ended up really bent...

I have been making random planforms and parts based on what scrap balsa I have.

Maybe I should get thinner rubber and/or use longer piece.. Not sure how thick, I think i used .125", 6" loop
Is .125" okay..? Because that's the rubber I have most of. Dug through my fridge and found a foot or two of thinner rubber.
When I launched, I was only halfway to stretching my arms all the way. xD

And there were no dents on the wings, so shouldnt have been hitting the handle.
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Re: Future Aviation Events

Post by twototwenty »

Yeah, I'm sure you would've known if the wings were hittng the launch handle.

Honestly, wood glue is going to be far too thick and heavy for this event...CA glue is really the way to go. The thinnest CA glue is less viscous than water, and the balsa should really soak it right up. I actually have been using extra thick Ca glue, which is a little thicker than water, and I haven't had any problems with it yet, although I haven't tried particularly vigorous launches yet.
retired1
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Re: Future Aviation Events

Post by retired1 »

Ambroid and some Duco glues are acetate (or similar) dissolved in a solvent. Typically acetone. They offer the advantage of easily being thinned as desired and then a tiny amount used. Most of the glue weight evaporates so is lighter than CA. It takes quite a while to set which allows you a bit of time to reposition stuff if needed. It can be dissolved with acetone easier than CA and will re-glue by softening with a touch of acetone and more glue added if needed. CA joints that were taken apart with acetone should be scraped or sanded to remove the old glue to get a good glue job. It is the difference of evaporation and internal setting.

Everybody has their likes and dislikes and some are very adamant on it. Techniques will be a bit different for each. Go to the new area "glue" for more discussion. The secret is in using just the right amount.

My tower students went to CA because of time.

When you laminate wood, it must be clamped--regardless of the type glue used or it will warp.

Based on what I have read, rubber will be 6-7" loop and a bit bigger than 1/8". Some people are using 1/4". That is probably a bit much for low ceilings and light gliders.

I have never kept rubber in the fridge. I use a cool dark place. Light is the killer.
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Re: Future Aviation Events

Post by illusionist »

What are the launchers generally made out of, and is a Y shape preferred, or simply a stick with a rubberband on top? With the stick, I'd imagine that the glider would bump into the top of the stick where the rubberband is attached.
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Re: Future Aviation Events

Post by retired1 »

Everything that I have read uses a wood stick. I think that most contest competition (not SO) use a stick with a hole drilled and filed near the top. One picture that I saw had the plane during launch just beyond the stick and it appeared to be 2-4 inches above the stick. I do not think that you will have any problem using a standard "hook" size and location on the fuselage. It evidently forces it up as well as there is some lift happening.
I remember cheap kiddie gliders from a long time ago and they did not hit the launch stick.
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Re: Future Aviation Events

Post by twototwenty »

illusionist wrote:What are the launchers generally made out of, and is a Y shape preferred, or simply a stick with a rubberband on top? With the stick, I'd imagine that the glider would bump into the top of the stick where the rubberband is attached.
My launcher is very crude; just an old helicopter elastic on a screw screwed into the top of a dowel, and I haven't had any issues with it. Now, it may take a little effort to get your launch technique to a place where your glider doesn't hit your launcher, but that is probably easier than building a y-shaped launcher. As for how to launch successfully, I have tried to assembly a decent walkthrough on the wiki, and would love to hear feedback about how clear it is.
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Re: Future Aviation Events

Post by corsair2014 »

is it possible to have more than one wing?

for example, i was thinking of a canard glider

one wing 15 cm (in the front), and a seperate wing that is 30 cm. is this legal, or do they add a cumulative total of wing span?
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Re: Future Aviation Events

Post by wlsguy »

corsair2014 wrote:is it possible to have more than one wing?

for example, i was thinking of a canard glider

one wing 15 cm (in the front), and a seperate wing that is 30 cm. is this legal, or do they add a cumulative total of wing span?
The rules are not yet released so you will need to wait a week or two before you know for sure (unless one of the people with an advance copy of the rules wants to chime in).
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