Quick-Build 

Quick-Build Foam Wing

The following notes detail the methods used to construct the wing panels.  This method gives the straightest, lightest, and certainly fastest and easiest method ever seen for constructing a stunter wing.
1. Vacuum foam cores to remove all dust.
2. Glue 3/8" thick trailing edge to both panels using Titebond or odorless foam compatible CA glue.
3. Lay 2"wide masking tape on panels just in front of trailing edge to act as a barrier, and carve and sand trailing edge to match airfoil contour.  Remove tape.
4. Place 1/16" x 1-1/2" trailing edge sheeting in place on rear of panel.  Tape front edge of trailing edge sheeting to the foam.
IMPORTANT NOTE: If your foam core has a slight "bow" in it, it is of no concern.  Place the panel on a flat surface, center of the bow upwards, and proceed to step #5.  The foam panel will straighten in the process of attaching the trailing and leading edge sheeting.
5. Fold the trailing edge sheeting forward by the tape "hinge," and apply foam compatible CA glue (medium) to trailing edge strip and to foam where sheeting will be in contact.  Return sheeting to the panel and hold in place with both hands, applying pressure against the sheeting so that the trailing edge maintains contact with the flat table top.  You will feel slight heat when the CA glue cures (15 to 20 seconds).  DO NOT USE "KICKER" - it melts foam!  You can glue booth trailing edge sheeting pieces in place in one step, or do one at a time.   One at a time is better, if a bowed core is to straightened.
6. Tape 1/16"x4" leading edge planking to core so that rear of sheeting corresponds to rear of foam "spar" in the core at both root and tip.
7. Fold sheeting back and apply a 1/8" wide band of foam compatible CA glue to the sheeting.  Return sheeting to the foam core and hold in place on a flat surface, as you did in step #5.
8. Once glue has cured, "roll" wing core forward and trim front edge of sheeting pieces so that they will overlap leading edge of foam core about 3/16" or so.
9. After trimming leading edge sheeting, prepare 6 to 8 pieces of 2" wide masking tape about 2 feet long.  Have them hanging where you can reach them quickly.
10. Holding wing panel leading edge upwards, "dribble" foam compatible CA glue into area where sheeting will contact foam.  Use enough so that full glue contact will result when sheeting is pulled into place, but don't worry about covering every bare spot.  A glue pattern similar to where "ribs" would be on a wood wing is fine.
11. Pull leading edge sheeting pieces down to core with one hand (at center of panel) and wrap tape completely around core with other hand, beginning at a trailing edge, around leading edge, and back to trailing edge to hold sheeting in place.   Quickly work towards each end of panel, wrapping the tape every 3-4 inches.   Re-tape as needed to be sure wood is fully in contact with the foam.
NOTE: A very slight moistening with water of the outer surface of the wood will allow it to bend to the leading edge curve more easily.   Allow to cure 15 minutes.
12. Remove all masking tape.  Block sand leading edge sheeting flush with foam.  Attach 1/4" leading edge pieces with Titebond or foam compatible CA foam.
13. Prepare sections of center section planking by edge-gluing pieces to width needed to cover area between leading edge and trailing edge planking.  It is important that the outer edges of center section planking be cut at a slant. or curve, so as to minimize stress points in the wing.  At rear of leading edge planking, the center section planking should be about 8-10 inches wide, measured from root of panel.   At trailing edge planking, it should be about 5 inches wide, leaving approximately a 45 degree angle to edges of center planking.
14. Glue center planking pieces in place using foam compatible CA glue.
15. Carve or sand leading edge to shape.
16. Add "capstrips" using foam compatible CA glue or Titebond.   These may be applied in a geodetic fashion or perpendicular to the trailing edge (similar to a typical balsa wing).  It is not a critical matter which you choose.
17. Block sand wing panels smooth.  True up root ends so that panels will join straight, with no gaps, no dihedral, no "droop," and no unwanted sweep of hinge line.
18. Add bellcrank/pushrod assembly to inboard panel, holding bellcrank pivot wire in place with 5 minute epoxy.
19. Join panels with 5 minute epoxy.  A pin at the leading edge and the trailing edge will keep the panels from twisting relative to one another.  You can use the cradles to hold the panels while you join them, but I prefer to hold the outboard tip against the floor, while I sight down the trailing edge to be sure there is no dihedral or droop.   As the glue cures quickly, this is not a long process.
20. Wrap the center section joint of the wing with 2 inch wide fiberglass tape, applied with epoxy or CA glue.
21. Add tips, tip weight box, and flaps as usual.
22. Drill a 1/8" hole in each foam "open bay" so that it can "breathe" into the hollow section of the wing.  This prevents the covering from "sagging" or "ballooning" as air pressure changes.
23. Vacuum the wings again before covering.  If using iron-on film, follow the manufacturer's instructions.  For a painted finish, cover wings with Starline PolySpan as it does not "sag" and touch foam when wetted with dope.   Dope contacting the foam will dissolve the foam.  This will not cause a major structural problem, but can affect appearance due to foam residue on the "back side" of the covering material.
24. "External" bellcrank pivot mounts of 1/8" ply are added after the wing is installed in the fuselage.  These are 1 inch wide by the width of the fuselage, and are to fit snugly between the fuselage side.  Epoxy them to the wing and fuselage sides, top and bottom of wing, and add a little more epoxy to the bellcrank pivot mount where it protrudes through the plywood.  Cut off excess pivot mount with a Dremel cutting disk.
25. Finish the rest of the model as usual.

Note: Foam compatible CA glue, 2oz bottle, $17.00