Perforated wing and its construction in three zones
A valved net-wing seen from below and a wing built in zones A, B, C of different materials
The upper drawing shows the valved wing from below, remaining perforated when it rises and closing solid when it falls. The lower drawing divides a wing into three lettered zones, A, B and C, and the note specifies the material of each: fir laths bound with sinew, feathered fustian, and starched taffeta, with paper allowed for a trial. The mesh of the net is to be made 1/8 wide.
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Valved wing seen from below
The upper figure shows the wing so that it stays perforated when raised and becomes wholly closed when it descends, viewed from below looking up. The drawing makes the opening-and-closing valve action legible from the underside.
Wing in three material zones A, B, C
The wing is divided into three zones with the mesh of the net made 1/8 wide. A is a fir lath bound with sinew and lightened with lime-wood; B is fustian with feathers glued on so the air does not readily escape; C is starched taffeta, with thin paper allowed for a trial.