How To Install Leading Edges On Biplane Wings

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For several years, a team from my local Experimental Aircraft Association (EAA) chapter has been building the wings for an EAA biplane my father began in the late 60s.  Currently, we are installing the aluminum leading edges on the wings.  As with all aspects of this project, it is quite a process.
Starting with a 4’x8′ 2024T3 .020 aluminum sheet, we cut, formed, trimmed, crimped edges, and drilled holes.  All the while, strapping and unstrapping multiple times, aluminum forms on the wing to ensure it fits every step.

A Twelve-Step Process

  • Step 1.  Cut off an 8′ x 16″ piece of aluminum to size from the full sheet.
  • Step 2.  Form the aluminum lengthwise around the wing’s leading edge, careful not to fold or crease it.  A smooth curved surface is critical for optimum lift.  This is done using a form/mold, then strapping premade forms into place and leaving for a few days.
  • Step 3.  Remove the forms and trim the long edges of the piece to fit precisely around the leading edge.  A long, really long straight edge, a precision measuring gage, sharpie, and sharp tin snips are needed for this.
  • Step 4.  Crimp the long edges.  This step uses a special tool that turns the edge slightly down so it fits firmly against the wooden spar once in place.
  • Step 5.  Reinstall the forms and mark the aluminum, top and bottom, where the holes will be drilled for screws.
  • Step 6. Remove the forms and mark matching holes on the spar.

The Halfway Point – Whew!

  • Step 7.  Drill pilot holes in the spars.
  • Step 8.  Drill holes in the aluminum

    leading edges
    Drilling screw holes in the lower right aluminum leading edge
  • Step 9. “Dimple” the holes in the aluminum so the screws recess.  This also required the use of a specialized tool.
  • Step 10.  Mix the adhesive, then, careful not to cover the holes in the spars, spread the adhesive on the spars and the leading edge of the ribs, on both the bottom and top.  This will require turning the wing over.
  • Step 11.  Carefully position the aluminum on the top and, beginning at the center, working out, screw the aluminum into place.
  • Step 12.  Turn the wing over and bend the aluminum into place reinstalling the forms from the center out, ensuring the holes on the aluminum and spar line up,
  • Step 13.  Starting from the center screw the bottom of the leading edge onto the spar.
leading edges
The left lower wing hangs with its leading edge installed

This was a five-hour process on one wing with four people working.  At the time of this writing, the leading edges have been installed on the two lower wings.  There remain the two upper wings as well as the upper center section to complete this stage of the building.

For a look at the progress we have made go to this link:  nancyhancock-cullen.com to see all updates.

When will be be done?  I don’t know, but I do know we are closer every week.  If you are in the area and want to see the project, we work every Tuesday afternoon from 1-4.  Email me at: Nhcullen@cfaith.com

 

 

I am a former air traffic controller, pilot, Aircoupe owner, married 42 years to a great guy. We live in a 125+ year old historic Victorian, enjoy cats, vintage anything, precious friends. My passion is Giving Lost Stories A Voice – Giving Found Materials Fresh Form and Purpose!

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