need help building scale emphanage
07-19-2003, 02:14 AM
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need help building scale emphanage
I’m getting ready to start a Marutaka J2M3 Raiden, and I’m going to have a lot of questions. I’m modifying the kit and one of the big items is the tail feathers. They’re sheet and I want to make them built up with a scale airfoil. Problem is, I’ve always built what the kit designer provided in the past, and I’m not sure how to go about doing it myself. I’d really appreciate you guys sharing your techniques. I’ve posted the view below to give you an idea what’s involved. The wingspan is 50”. Thanks in advance.
John
raiden top
John
raiden top
07-19-2003, 10:39 PM
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need help building scale emphanage
One method is to lay down a 1/16 sheet balsa outline of the stab. glue onto that a 1/4 by 1/8 balsa L.E. 1/4 by 1/4 T.E. in one piece.Cut some 1/16 by 3/8 balsa strips. Cut and glue where you would normally put ribs. Put two thicker ones where the stab saddle is. Turn it over and do the same on the other side. Sand the airfoil into the ribs. Sand it 1/16 lower to allow for the sheeting. Sheet with 1/16 balsa. Makes a very light, very rigid structure. Any question, just holler.
07-22-2003, 02:24 AM
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Empennage
Okay, I've got the picture. I downloaded WinFoil and have the ribs ready to draw out- do you have a suggestion on which airfoil? I've got a NACA 0012 symetrical for the vertical fin and an NACA 2412 for the horizontal stab. I was going to print them out, trace 'em on a balsa sheet, split 'em length-wise (removing 1/16") and glue to the center piece. (not real confident of my ability to sand a proper arfoil as you described) Is this reasonable??
John
John
07-25-2003, 04:32 PM
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need help building scale emphanage
I suggest you use either 0012 or 0009 (whichever is closer to scale) symmetrical airfoil, or inverted flight might be tricky.
Once you have your airfoil shape & size chosen, create a LE block by drawing a vertical line a standard distance (e.g., 1/2") back from the LE. The TE block can be added from the known control surface position, or estimated at 75% chord.
Then draw an offset line on the inside of the airfoil representing your skin thickness (e.g., 1/16"). Then add squares to top and bottom surfaces at 25% chord to represent spar notches- the spars can be sized to be about 1/4 the max thickness of root airfoil and can extend about 2/3 to the tip airfoil.
- George
Once you have your airfoil shape & size chosen, create a LE block by drawing a vertical line a standard distance (e.g., 1/2") back from the LE. The TE block can be added from the known control surface position, or estimated at 75% chord.
Then draw an offset line on the inside of the airfoil representing your skin thickness (e.g., 1/16"). Then add squares to top and bottom surfaces at 25% chord to represent spar notches- the spars can be sized to be about 1/4 the max thickness of root airfoil and can extend about 2/3 to the tip airfoil.
- George
