Multi-function trailing edge devices and associated methods

A system, comprising:

• a first portion of an external fluid flow body having a first flow surface and a second flow surface facing opposite from the first flow surface;
• a second portion of the external fluid flow body, at least part of the second portion being positioned aft of the first portion, the second portion being pivotable relative to the first portion about a pivot axis that is positioned at the second flow surface or between the first and second flow surfaces so as to move relative to the first portion between a neutral position with the second portion generally aligned with the first portion, a plurality of first positions with the second portion deflected in a first direction relative to the neutral position, and a plurality of second positions with the second portion deflected in a second direction opposite the first direction relative to the neutral position;
• a flexible surface positioned proximate to the first and second portions, the flexible surface having a first shape when the second portion is in the neutral position, a second shape when the second portion is in at least one of the first positions, and a third shape when the second portion is in at least one of the second positions, a gap being positioned between the flexible surface and the second portion when the second portion is in at least one of the second positions;
• a guide structure coupled between the first and second portions;
• and
• an actuator operatively coupled between the first and second portions to move the second portion relative to the first portion.