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Old Feb 29, 2008, 11:34 AM
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Chatenever's Avatar
USA, CA, Oxnard
Joined Mar 2006
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Chuck Glider or Catapault Launch glider plans?

I'd like to find a plan to scratch build a little glider similar to the ones I used to buy at the dime store when I was a kid... you know, the type that was built from 1/32" sheet balsa and you'd simply chuck it, or launch it from a hand-held catapault (rubber band on the end of a stick). I want to build it out of either Blucor FFF or balsa, with a wing span of 15-25". Hopefully, there are some simple plans out there that will fly better than the Walmart styrofoam gliders, without getting too fancy. I'd like to use it with my 5-year-old grandson, so it needs to be expendable ... no ribs, no covering, no vacuum bagging, just sheet stock and glue.

Got Plans???

(I also posted in the HLG forum and they suggested that this might be a better choice).
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Old Feb 29, 2008, 12:11 PM
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TLyttle's Avatar
Keremeos, BC Canada
Joined Mar 2004
2,639 Posts
If I had a scanner, I could email you a few...

Best catapult glider out there is Lloyd Shales' Sparrow: preshaped wing laser-cut parts, GREAT flyer... Kits are available, but you may have to hunt a bit; worth your time to look.
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Old Feb 29, 2008, 12:16 PM
B for Bruce
BMatthews's Avatar
The 'Wack, BC, Canada
Joined Oct 2002
11,289 Posts
If you want them simple and disposable then stick with a smaller size and made from thinner wood.

1/16 works very nicely up to a wing span of around 16 to MAYBE 18 inches or it may rip the wings off at 18. But at 16 it'll easily be strong enough.

Designs can be as fancy or simple as you want. But you will need generous dihedral and some very basic proportions. Try this....
  • Wing from 1/16 x 3. Span 14 inches. Simple V dihedral with the wing tapering from 3 inch wide at the root to 2.5 at the tip raked back on the leading edge only. Join the two panels with one flat and the other 2.5 inches in the air.
  • Fuselage stick made from 1/4 x 1/2 balsa. Taper from the nose all the way to the tail so it is 1/4 x 1/4 at the tail. Length 12 inches.
  • Stabilizer will be 6 inch span with a straight trailing edge and have a 2 inch chord at the root and taper to 1.5 at the tips. The tail surfaces should be made from 1/32 wood or you can sand the 1/16 down quite aggresively to thin them and lighten them.
  • Fin will be from 1/32 or sanded down 1/16 as well and be 2 inches high, 2 inches chord at the root and 1.5 inches at the tip.
  • Glue the stab onto the bottom of the stick. Note that you get your decalage angles automatically from the taper of the stick. Now glue the fin onto one side of the stick for a nice strong joint.
  • Mount the wing to the fuselage so that the leading edge is 3.5 inches back from the nose. Because of the dihedral joint you'll want to cut a shallow V in the top of the stick so there is a tighter glue joint. THis is one spot where some 5 minute epoxy is good to use so it fills the joints.
  • Use some modelling clay to balance the model at around 1 inch back from the leading edge. Then test glide it and alter the nose weight until it has a nice glide.
  • Throw it like your grin depends on it...

There's some other fine details like using your moist warm breath to warp in some turn into the fin and some washin on the inside wing. Set up the model for a right handed launch so it turns to the left in about a 50 foot diameter circle. For a southpaw launch to the left set up the model for a right hand turn. That way it crosses over on the launch and avoids becoming a lawn dart.

Throwing is fine but a #32 rubber band or two with a little stick makes a great catapult launcher. Link them together to be longer rather than wider. A small finishing nail glued into the belly of the model a little bit in front of the leading edge of the wing so it sticks out about 1/4 inch works well.

From there you can do profile models of old time fighters or jets. Flat wings on these work just fine. Just mount the stabilizer so it has an angle similar to this one described here so you have some positive stability.

I'd avoid going over the 14 to 16 inch span since once you do the forces in the launching require more strength from the wood and then you're into thicker wood that needs to be carved down to airfoil shapes. And then there goes the simplicity.

Another avenue to try for some small backyard fun is little 6 inch gliders made with 1/32 sheet for the wings and tail and 1/8 sticks for the fuselage or if you do them with a full fuselage then 3/32 sheet.

Experiment with regular layouts, biplanes, canards, flying saucers, flying wings and any other shape your imagination can conjure up. The models almost build themselves as this size. No need for any sort of finishing other than some felt pen decorations if you want.
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Old Feb 29, 2008, 04:59 PM
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InTheLift's Avatar
Torrance, California
Joined Jan 2004
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What he ^^^ said. For fun flying, the TLAR method works just fine.

Also nice for catapult flying are the White Wings "paper" gliders. They are pretty small, but perform well once trimmed out...I've lost more than one to OOS flights. They are also fairly durable...nice for little hands.
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Old Feb 29, 2008, 08:31 PM
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USA, CA, Oxnard
Joined Mar 2006
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Quote:
Originally Posted by BMatthews
[*]Fuselage stick made from 1/4 x 1/2 balsa. Taper from the nose all the way to the tail so it is 1/4 x 1/4 at the tail. [*]Glue the stab onto the bottom of the stick. Note that you get your decalage angles automatically from the taper of the stick. Now glue the fin onto one side of the stick for a nice strong joint.
Thanks!!! That's EXACTLY what I was looking for. Only one thing is not clear to me ... When I taper the fuselage stick, do I trim the top or the bottom? If I trim the top, I will have a positive angle of attack on the wing. If I trim the bottom, I will have a negative angle of attack on the stab. Does it matter? Or does it work out exactly the same?
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Old Feb 29, 2008, 09:24 PM
B for Bruce
BMatthews's Avatar
The 'Wack, BC, Canada
Joined Oct 2002
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It's the same either way. The model will adjust itself in the air so both ends are happy. Remember that the fuselage is just a way to hold the other stuff together. The angles of the parts on the fuselage don't mean a thing. It's the angles of the parts to each other that is important. The term we use often for this angle of the wing to the stabilizer is "decalage" or some call it "horizontal dihedral" although the last one is a very bad description. For that matter the "decalage" term is not really right either since the original use of the word was to describe the difference in incidence angles of the two wings of a biplane. But it's come to be the wing to the stabilizer in the model airplane world.

Now you can go forth and dazzle others with your trivia knowledge...

Post back pictures of the first efforts along with the grins of the young (and old ).
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Old Mar 01, 2008, 11:44 PM
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TLyttle's Avatar
Keremeos, BC Canada
Joined Mar 2004
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One minor alteration to an otherwise excellent description, Bruce: make the center section of the wing flat, giving a solid glue joint at the fuselage, add polyhedral to the tips. This avoids the dreaded (in my experience) V-dihedral-fuselage glue joint that frustrates so many beginners; they ALWAYS break there!

I had a beginners' HLG published for the MAAC beginners program. Those who tried it were happy with the simplicity of that joint, and the performance of the model. Lloyd Shales' Sparrow also uses this configuration with (to my experience) great success.

Please try it, Bruce, let me know what you think...
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Old Mar 02, 2008, 12:35 AM
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USA, CA, Oxnard
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Quote:
Originally Posted by TLyttle
make the center section of the wing flat, giving a solid glue joint at the fuselage, add polyhedral to the tips.

Can you suggest an appropriate dimension along the 14" span where to make the polyhedral break? Also, then how much rise to each wing tip?
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Last edited by Chatenever; Mar 02, 2008 at 12:41 AM.
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Old Mar 02, 2008, 01:35 PM
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United States, GA, Warner Robins
Joined Mar 2005
501 Posts
Here is a little CLG design I've been flying for about a year now. Have made 5 of them to date and have managed to litter trees and countryside with them. The climb is truly awesome using a loop of 1/4 for the catapult. They whistle all the way up and glide like crazy. Mine will do over 50 sec in dead air in optimum trim. Just follow the instructions and it should work ok. Contact me if you build it and have trouble.
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Old Mar 02, 2008, 08:55 PM
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Keremeos, BC Canada
Joined Mar 2004
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Chatenever: crack the tips about 4" in, bend up 1 1/2", more if it needs to be more stable. Smear a coat of glue over each side of the cracks.

Love your dog...
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Old Mar 02, 2008, 11:12 PM
B for Bruce
BMatthews's Avatar
The 'Wack, BC, Canada
Joined Oct 2002
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Quote:
Originally Posted by Chatenever
Can you suggest an appropriate dimension along the 14" span where to make the polyhedral break? Also, then how much rise to each wing tip?
I'd say 3 inches in for each tip and the tips should be raised the same amount as for the simple V dihedral. So 1.25 inches per tip.

This is a little less than Terry's suggestion both in the size of the tip and the amount (although the angle will remain about the same). Perhaps try two models. One each way.

Truth be told I was thinking of saying the same thing as you Terry but I flip flopped over the two wing joints rather than one. One joint won out this time....
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Old Mar 03, 2008, 08:24 PM
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Keremeos, BC Canada
Joined Mar 2004
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When we were both much younger, Bruce, I used to have the kids build a vee-dihedral HLG, and the failure rate at that joint was too high to suit me. I designed another using the poly setup, and the failure rate dropped dramatically. It was published in the MAAC magazine, and I got quite a bit of feedback, all of it positive.

Cracking the joints also worked far better than cutting/reglueing, as it leaves most of the fibres intact, and then the overglue just adds to that usually-weak joint.

I do know that the only one of these models to fail completely was the one that was chewed up by the owner's dog...
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Old Mar 03, 2008, 09:19 PM
B for Bruce
BMatthews's Avatar
The 'Wack, BC, Canada
Joined Oct 2002
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There you go.... straight from the horse's mouth.....



.....(ooooo I'm gonna pay for that one I suspect )....
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