Expert opinion

Plywood in the aircraft construction

Aircraft plywood has special flexibility, high strength and low density. Having a small specific weight, aircraft plywood has impeccable durability. Birch veneer serves as the basis of aircraft plywood. The veneer is connected in three or more layers. Aircraft plywood is available in thickness from 3 to 16 mm. There are also very thin ones, on the order of one millimeter.

Aircraft plywood gets strength comparable to low-alloy steel due to its special production technology. The directions of the fibers are perpendicular to each other. Each layer is mounted with a structural grid and intersects with the next layer, clearly at right angles.

The first layer of plywood is its middle. Next, the layers are glued on top and bottom. Therefore, each sheet of aircraft plywood always consists of an odd number of veneer layers.

One of the types of marking of aircraft plywood is the presence of surface processing, namely:

- One-sided sanding of a sheet of aircraft plywood is marked with the abbreviation S1

- The abbreviation S2 denotes, respectively, the presence of sanding of two sides of the plywood surface

- The absence of sanding is marked as NS

As a rule, aircraft plywood is made of birch veneer, which is glued with bakelite composition-with the addition of special plastic.

Depending on the type of bakelite base, aircraft plywood is divided into the first and second grade (marking A and B).

Cutting as well as processing of aircraft plywood is quite complicated. This is simplified by the small size of the plywood sheets. Therefore, large-sized sheets of aircraft plywood are not encountered. As standard, the maximum size of a sheet of aircraft plywood is 1525mmx1525mm. Minimum size is 800mmx1525mm.