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Last Update: june 3rd 2019

Basic Structure

Wing

buying 26 ft. Sitka Spruce beams:

wing jig:

The main spar is made of 6 boards sitka spruce, each 13/16" thick. Each board consists of 3 single elements, height 4" + 4" + 1", total height 9". Due to the fact that my Laser will get a non-white paint scheme I decided to use Aerodux 185 for glueing all structural wood parts. It's a mess to work with, compared to Epoxy, but the bonds are absolutley resistant to heat:

cut taper to boards:

stacking 6 boards with Aerodux185, glue joints according to ANC-18:

sanding board steps to smooth taper:

routing pockets into spar:

The webs of the ribs are milled of 1/16" birch plywood. The webs are reinforced with 1/4" x 1/4" surroundings of fir. All ribs assembled in cnc-milled jig. Then glued gussets to corners:

The rear spar is made of 2 layers sitka spruce 7/8". I tapered it with the cnc-mill and I even add the airfoil contour:

I create a jig extension wich hold the rear spar in perfect distance and angle related to the main spar. This eases up rib installation:

installation ribs aft of rear spar, triangle corner blocks fir 1/2"x1/2" used at every joint:

create jig extension for leading edge with cnc-mill similar to rear spar. CNC-milled leading edge with airfoil contour. This time I added grooves for the ribs fwd of main spar. This simplyfies glueing ribs into position:

I was done with the ground-mounted jig and designed a new one, moveable with wheels. The wing is fixed in circular holders wich rotate 360° on the jig cart:

CNC-milled gussets for stringer/rib intersections. Gusset size is decreasing from root to tip. Stringers made of 1/2" x 1/2" sitka spruce, needed to be scarfed according to ANC-18:

Installing trailing edge ribs aft of rear spar. 4 ribs on each side of wing. Left space will be filled with aileron!

achieved a major step: internal wing structure DONE !