6 mm × 24-inch Carbon Fiber Tube
2.00 3.50 .24 .50 1.00 4.00 1 -inch lite ply⁄8 6.00 EVX-48 Wing Fixture
The dimensions of the fixture used to construct the wings (above left) are shown in this drawing. The assembled wing fixture (above right) is ready to aid in quick and accurate wing construction. Next, the ribs were slid on the
rods (below left), and foam spacers (below center) used to space the ribs. Both the leading edge and trailing edge pieces (below right) were then glued in place.
2-inch × 6-inch × 22-inch Foam Block
22.00
Building the wings
As noted above, I built the wings on a sim- ple fixture I made from a foam block, two lite plywood side supports, and two 6 mm carbon fiber tubes. While the wings can be built without the fixture, it is well worth the time and effort to make it. Just be sure that any tubes or rods you use on the fixture are per- fectly straight as the wing will follow their shape. I have to say, I don’t think I can build a wing any straighter than those on the EVX. I also made a rib spacer out of 6mm Depron® foam. This really helped maintain the rib spacing while adding the leading and trailing edges.
The wing construction is reasonably straightforward with leading and trailing edge sheeting and top and bottom spars. The
leading edge includes a spar for centering the ribs and the trailing edge sheeting is capped with a 1⁄4 × 3⁄8-inch balsa strip. Start the wing construction by gluing 1⁄8-
inch square sticks to both sides of the 1⁄8 × 3⁄8-inch leading edge spar, forming a “T”. If you are using the wing fixture, slide the ribs onto the tubes and secure the tubes onto the fixture side supports with rubber bands. Please note that ribs 3 and 4 have a notch for the aileron servo mount. Make sure that the notches are correctly positioned for a right and a left wing.
Space the ribs with the rib spacer and in- sert the leading edge spar into the leading edge spar slot in the ribs. Square the ribs to the fixture rods and glue the end ribs to the leading edge spar. Glue the bottom trailing
edge sheeting to the end ribs and check the alignment. If everything is aligned, glue the remaining ribs to the leading edge spar and the bottom trailing edge sheeting. Glue the top spar and top trailing edge sheeting in place. Remove the wing from the fixture side supports, flip it over and place the rods back on the fixture supports. Glue the bottom spar in place. You can now remove the wing from the fixture.
Gently sand the leading edge spar to match the curve of the ribs. To prevent sand- ing the ribs and changing the airfoil shape, protect the ribs with a piece of masking tape. I use 1½ inch wide blue painters tape for this. The wing leading edge sheeting can now be glued in place.
With the leading edge sheeting in place,
The left wing is seen here (at left) with sheeting and caps strips fitted. The wing tip is yet to be added. The ailerons (above) use the same construction as the tail feathers.
FLYING MODELS 23
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