BRYAN AIRCRAFT CO.
COVERING THE WINGS
1. Scribe a centerline on the flanges of all ribs. A coating of blue will make the lines easier to see when holes are drilled through the skin later.
2. Straighten all nose ribs.
3. Slip the inboard 12-foot section of formed skin into place making sure that there is sufficient skin to cover the No. 1 rib when it is squared with the spar.
4. Cut one by four boards down the center and put two lengths of these inside the rear spar channel. (One length in outboard 12 feet)
5. Place five 2-foot lengths of 2 x 4s under wing.
6. Place straps around wing skin between ribs 1 & 2., 2 & 3, 3 & 4, etc.
7. Tighten straps and tap leading edge with rubber hammer to drive nose ribs into skin nose contour.
8. Tap rear spar at root or tip with rubber or plastic hammer until No, 1 rear rib is 90 degrees to main spar.
9. Clamp brace from rear spar and rib joint to main spar near splice plate fitting to maintain alignment of all rear ribs.
10. Stretch a string over the shear web and draw a line with a ball point pen to mark the shear web location.
11. Using the same method, scribe spar rivet lines 1/4 of an inch in from the edge of the angles. Stop the front angle line at rib No. 10 as the angle gets too narrow for riveting outboard of this point.
12. Sight leading edge main spar and rear spar for straightness. Check for absence of twist by use of No. 1 and No. 15 top rib templates. There is no twist in the wing so alignment is simply a matter of sighting the tops of the templates and twisting the wing until the tops are parallel.
13. Starting at rib No. 1, drill all spar rivet holes. Previous scribing of lines on the spar or, if an accurate hardened drill guide is available actual predrilling of the spar will make later drilling through the skin more certain of piercing the spar on the proper line.
14. Use a plastic triangle or piece of metal cut at a 90 degree angle to lay out rib rivet lines perpendicular to web reference line.
15. Mark rib rivet locations with a ball point pen. Start 3/8 of an inch from the edge of the spar, space holes 1 1/2 inches and stop 1 1/2 inches from the leading edge. (Exception: No. 1 rib where spacing is 1 inch) Vary spacing of next to last hole when last space would be less than 3/4 inch.
16. Drill rib holes through skin only. (# 41 Drill)
17. Use picks to move rib so that centerline is centered in holes. Drill while holding rib. Place Clecos in drilled holes. When rib cannot be moved, go on to the next one. Such ribs can be moved and drilled after straps are released.
18. Lay out rear rib lines and holes as above except that lines should extend from nose rib line aft to actual center of rear ribs. Mark rearmost rivets 1/2 inch, ahead of rear spar.
19. Release straps from wing. Keep all cloches in place.
20. Drill rear wing ribs, top side.
21. Drill rear spar skin holes.
22. Countersink all holes except those in No. 1 rib and adjacent 4 holes in spar cap
23. Remove skin, clean out shavings, rivet bottom inboard skin extension to main skin and reinstall skin. (after any tight ribs have been moved and drilled)
24. Rivet top of skin to wing (except No. 1 rib and adjacent 4 holes in spar)
25. Turn wing over, reinstall wooden strips and restrap.
26. Check very carefully for straightness and lack of twist.
27. Repeat all steps outlined above for bottom of wing. Exception is method of extending forward rib rivet lines from top line at nose radius back to spar. (since the top of the rib is already fixed, it cannot be moved at this stage) Use Pop rivets in all ribs. Be sure to install flap hinges in proper location on rear spar.
28. Install splice plates to inside edge of skin at outboard end between ribs 15 and 16. No trimming of skin is necessary.
29. Install outboard skin on wing and strap as above.
30. Drill and rivet as with inboard skin. Don't forget to include aileron hinges on top of rear spar.
31. Be doubly careful to check for twists curved rear spars and leading edges and especially check No. 30 rib with the contour templates to insure that the airfoil contour is not lost through deflection of the rear ribs which have little alignment stability near the tip. Perform this last check very carefully just before drilling the bottom of the rear ribs or rear spar.
32. Install wing tip spars using No. 30 top rib template and wing tip template to get the rear spar at the proper angle.
33. Install tip skin splice plates and rivet to outboard skin.
34. Install tip skin and tip, Use tip template to prevent twist.
35. Install tip skin rib next to outboard end of aileron.
36. Trim skin at wing root even with rib flange allowing a little for filing.
37. Install .063 reinforcing plates on top and bottom of skin over No. 1 rib.
38. Install aileron actuating push pull tube,