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Old Mar 29, 2012, 01:17 AM
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free flight plane...HELP needed

Hey guys,
I'm about to make my first free flight balsa model from scratch....I wanted to start with an easy one...so i decided to make the Pilatus Porter - rubber-powered free-flight plane from this website:http://www.rc-airplane-advisor.com/f...ane-plans.html
But while i was checking there build guide...http://www.rc-airplane-advisor.com/p...-sequence.html
In the wing part...they said.."Start building the wing first. Glue the ribs with CA glue to the underside of the sheet balsa wing half, one rib at a time. Notice that the ribs cause the wing to curve into a nice airfoil shape."But how can a balsa wood reshape itself....please help or do they use some blasa paper or what.....P...Please help me
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Old Mar 29, 2012, 02:55 AM
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Balsa is a fairly soft wood. It bends easily, particularly when in thin sheets. You can clearly see that in the second picture in that build guide.

Steve
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Old Mar 29, 2012, 03:56 AM
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You might want to use something slower than CA so you can make adjustments before glue sets. Of course, for the wing sheet to the ribs you will have to figure out how to hold things in place while the glue dries! Pins and/or weights. Elmer's white glue, Titebond, Ambroid, Duco, etc. The first two clean up with water and you'd have to stick your nose in it to smell.

That's a nice looking design. You may enjoy looking at the following sites where they have some similar designs:
http://www.parmodels.com/Plans/Free%20Flight.htm
http://www.houseoffrog.co.uk/index.htm
I especially like the Dart Kitten in the junior series scale, though as a low wing design it might be harder to fly.
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Old Mar 29, 2012, 08:31 AM
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Thanks alot guys....
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Old Mar 29, 2012, 09:37 AM
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Just out of curiosity....can i use foam instead of blasa..
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Old Mar 30, 2012, 12:44 AM
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Of course, at least for small models, though you might need something stronger at the nose block and motor peg. But of course it depends on the material. Needs to be somewhat thicker than a balsa sheet would be. If the Porter is 12 to 16 inch wingspan I'm guessing you'd want 1 to 1.5mm (.040" to 1/16"). I used to fly some foam ff gliders when I was a kid. Later, they made foam Sleek Streaks. I have seen some beautiful scale models done with formed foam sheets. (And maybe some carving.) One was a pistachio (8 inch span) P-47 that would fly close to a minute outdoors. I wonder how George kept finding it in the grass?

If your foam seems kind of soft, consider a thin balsa strip at the leading edge, or perhaps a really thin bamboo strip.
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Old Mar 30, 2012, 11:57 AM
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Originally Posted by zoheb_rox View Post
Just out of curiosity....can i use foam instead of blasa..
Balsa has the advantage that it is more stiff along the grain than it is across the grain. This is why cutting the parts to align the grain of the wood is so important for many parts of your model. For example a common beginner mistake is to cut out the fin with the grain running horizontal instead of vertical on the part. The resulting fin is very fragile and prone to breaking very easily. But the same part cut from the same thin wood with the grain running vertically is far more strong and will withstand a lot of mishaps.

Working with foam that has no grain is a whole other kettle of fish. You'll find that the foam for this little all sheet Pilatus needs to be thicker to achieve the same strength. But with it being thicker the wings won't be able to curve like balsa does so well across the grain and it'll be far less able to achieve a smoothly cambered shape. And "optimum" sheet foam design would start with a different approach.
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Old Apr 01, 2012, 02:01 AM
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There are tricks to get foam to curve, though of course a balsa wing will be thinner, and may perform better as a result. Lots of info in foamie sections here.
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Old Apr 01, 2012, 02:58 AM
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Foam is certainly possible. I make most of my small models from foam these days, but I've either designed them that way or they need some modification to work well as foam. E.g. with Depron and a few other foams it's relatively easy to get a decent cambered airfoil without the need even for ribs but there are definite techniques that need to be learned...in my case mainly by trial and (lots of) error.

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Old Jun 28, 2012, 07:56 PM
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Originally Posted by zoheb_rox View Post
Hey guys,
I'm about to make my first free flight balsa model from scratch....I wanted to start with an easy one...so i decided to make the Pilatus Porter - rubber-powered free-flight plane from this website:http://www.rc-airplane-advisor.com/f...ane-plans.html
But while i was checking there build guide...http://www.rc-airplane-advisor.com/p...-sequence.html
In the wing part...they said.."Start building the wing first. Glue the ribs with CA glue to the underside of the sheet balsa wing half, one rib at a time. Notice that the ribs cause the wing to curve into a nice airfoil shape."But how can a balsa wood reshape itself....please help or do they use some blasa paper or
what.....P...Please help me
Pretty easy!
Once you cut your balsa wings, (grain wise) just use a damp cloth or paper towel and run it along the top of your wing panel, until you're able to curve the wood without cracking it, and not getting it to wet either, Then glue your ribs under the wing with Ca glue, using ca kicker and you're done. If you don't have CA kicker you could pin the ribs from the top of the wing, until it cures.
A good idea is to mark the underneath of the wing at the rib's position, before gluing.
I m building the same model, in Depron, with an HH Champ R/C brick.
Also curved my foam wings in the oven!
Good luck!!! And happy building! Believe me, building is the best part of this hobby, I have been doing it for as long as I can remember! Gotta Love Balsa!

Doug
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