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Thread: Building technique: Utilizing a Wing-Jig, Scale P-51 "Speed Wing"
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Old 02-28-2015, 01:02 AM
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Iron Dog
 
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Prepare the plywood Washout Cradles:
  1. Line up the two root (straight) Washout Cradle pieces, and the two tip Washout Cradle pieces (angled forward at negative 3-degrees). Each is marked “front” and “back.”
  2. Glue four ¼” diameter balsa circles fairly evenly spaced along the length of each type of the jig pieces, each with a drop of medium CA. (Do not place any in the dead-center of the cradle pieces, as the bolt and wing-nut will pass approximately through the center of the cradle.)
  3. Glue a second circle directly on top of the first.
  4. Put a drop of CA on top of the second circle and carefully, but relatively quickly align the front edges so that the assembly is “square” and the ¼” cradle cut-outs for the jig rods are properly aligned.



Note: This particular CAD-designed, laser-cut, wing short-kit comes with a matched pair of laser-cut secondary jigs (I refer to them as "cradles") that hold both rods at the correct washout angle so when built as suggested on a wing jig, there is no variance from one wing panel to another. (My goal has been to learn from every mistake I have made over the last 20 years of building, and incorporate these lessons into improving my designs towards approaching making everything relatively "idiot-proof.") The cradle at the root is level; but the one at the tip is angled, holding the rods at 3 degrees washout.

These washout cradles are potentially unique to this design. I've not seen any other kits come with them; but, it just makes sense to do it this way, so someone else has probably thought of it, too. So, when building any other wing, without custom washout jigs, one can use a scrap piece of 1/8" (or thicker) plywood as a spacer under the rear jig rod at the tip section of the wing jig. This is a quick and easy way to add a very gradual twist to the wing ribs from root to tip, and build in washout into any wing. One could use a bigger spacer, to increase the washout, as desired.
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