Plywood covering on lower side of Myrsky's port wing is under way
Torstai 12.9.2019 - Member of Tuesday Club
The covering of the lower side of Myrsky’s (MY-14) starboard wing was finished in early autumn and the work on the port wing could be started. The lower side between the wing spars will be covered with plywood. On the trailing edge side of the rear spar the aileron and flap will be assembled. The leading edge in front of the front spar will be covered later.
Pieces from 3 mm thick plywood sheet were cut diagonally to cover an area at the tip of the wing. These sheets are placed on the area between the spars to cover the area between 10 ribs, starting at the wingtip. One more sheet of plywood will be needed before the whole lower side of the wing is covered. The edges of the cut sheets were beveled for a lap joint and the lower side was protected against moisture using lacquer tinted red.
Screws will be used to make sure that the plywood is pressed tightly against the ribs and the supporting battens between the ribs. The holes for the screws were drilled on the plywood sheets. Three screws per batten between the ribs were used. Flathead screws are used and the matching beveling was drilled on the plywood sheets. Before gluing the correct positioning of the plywood sheets was ensured.
Epoxy glue and Erikeeper Plus glue was used when gluing the plywood sheets into place. Erikeeper Plus wood glue was used on the battens between the ribs.
Then the screws were fastened. A screw was placed into each hole, then a cordless screwdriver was used to fasten them through the plywood into the battens between the ribs. The work was finalized using a manual screwdriver so that the screw heads were about one millimeter below the plywood surface. The indentations on the surface will be covered and coated later.
The gluing of the plywood sheet edges on the front and rear spar was not secured with screws but using staples. The staples were “shot” on the plywood through small protecting pieces of plywood so that the surface of the plywood is not damaged. The proper fastening of the staples was secured using a hammer. When the glue has dried the protecting pieces of plywood and staples will be removed.
Finally, a thick strip of plywood was placed on top of the lap joint of the plywood sheets. Clamps were used to secure the strip and a metal weight was placed on top of the strip. Now the lower surface of the port wing had been covered from the wing tip as far as the auxiliary fuel tank / bomb rack. The plywood sheet covering this area is already under work.
Photos: Lassi Karivalo
Translation: Erja Reinikainen.