Sailplane carry-through structures made with composite materials

The carry-through structure, which joins and transmits toads between aircraft wings and fuselage, is a box-and-beam configuration made from composite materials In the RP series of all composite sailplanes, Increases in the size and weight of these aircraft increased the complexity of their carry-through structures, RP-1 has an interference-fit, box-and-beam configuration that was repeated in RP-2, but it failed during static testing because of peeling of the box capstrips at about 95% of design load, Because of this failure, the RP-2 carry through was redesigned with clearance between the box and beam and with pins transferring the bending loads: this redesign was adopted and modified for RP-3, The RP-1, RP-2, and RP-3 carry throughs and associated flight-worthiness tests are presented here and their implications for aircraft design with composite materials are discussed.