The wings are built up as a simple ladder frame with drag and anti-drag wires.
These wing covers are presewn at the factory into "envelopes," which the builder slides over the completed wing frames. The ribs, which are pre-bent to the right shape, are slid into presewn pockets on the top and bottom of the wing to give it a semi-symmetric airfoil shape.
The ailerons and flaps are similarly constructed of a ladder frame and covered with presewn envelopes, though no additional ribs are required. The frames are tapered from one end to the other, as are the envelopes, which makes the covers get tighter the further they are slid on. The last couple of inches are real hard to pull on. A little silicone lube helps; be careful not to use too much or paint won't stick!
