All of the above sailplanes and some with numbers in between (assigned by various builders) have flaps that are connected by a carry through assembly of welded steel parts and riveted aluminum drivers that engage the inboard flap ribs when the wings are assembled on the fuselage.

Variations in builder's assembly in this area indicate that each HP sailplane should be inspected to insure that drivers do go a minimum of 1/2" into their respective flap ribs.

Installations that do not meet this minimum engagement dimension can be corrected by replacing either or both parts No.18-417 with thicker plates. We can furnish material of proper thickness if you send us sketches of your present plates. Mark each one left or right and the thickness needed to extend the driver to a position 1/2" into the flap root rib. New rivets will be included. If there are rib-skin rivet heads in the way, new spacers should be notched to clear them when the drivers go into the ribs.

Security of the metal flap ribs is essential to safe flight so frequent inspection for their integrity should be made. Be sure that an AN 470-3-3 rivet is installed in each corner trailing edge of all flap sections. Use only Dexter Hysol EA 9410 adhesive and prescribed cleaning methods for cleaning metal when making repairs where bonding is necessary.