Wing construction is fairly standard, except the spar is a kind of ladder structure. The main advantage of this is that all the ribs can be slotted in dry.

The disadvantage (for a builder like me) is that while a traditional spruce top an bottom spar holds the wind firm in two directions this ladder spar can allow the tip to move backwards and forwards while gluing and I let mine move backwards by ¼” leaving my spar a bit bent. - I spotted this and was able to pin it straight while sheeting the front portion of the wing so no permanent damage done!