| 摘要 |
<p>Internal ribs for supporting a fabric in aerofoil form are made of semi-rigid synthetic foam material having a closed cell structure. Pref. the ribs are partly reinforced with a batten of poplar and have a curved and perforated profile which is known as a 'Clark' structure, for controlled twist depending upon which face of the aerofoil is upwind. Suitable for shaping sails of 'Dacron' (RTM), bonded to the edges of the ribs by suitable adhesives, mounted with the fold of the sail slipped over a mast, and controlled by an external wishbone pattern boom, e.g. for sailing surfboards, sand yachts, etc.</p> |
