Deployable aerodynamic devices with reduced actuator loads, and related systems and methods

An external flow system, comprising:

• an external flow body;
• a deployable device carried by and movable relative to the external flow body, the deployable device including a first component pivotably coupled to the lifting body at a first location, and a second component translatably coupled to the lifting body at a second location, the first and second components being pivotably connected to each other at a third location;
• and
• an actuator device operatively coupled between the external flow body and the deployable device, the actuator device being positioned to move the deployable device along a motion path between a stowed position and a deployed position, the motion path having a first portion over which the load delivered by the actuator device increases as the deployed device moves toward the deployed position, and a second portion over which the load delivered by the actuator device decreases as the deployed device moves toward the deployed position, the first portion being between the stowed position and the second portion, wherein the first component includes a first panel, the second component includes a second panel, and the actuator device includes at least one actuator coupled between the lifting body and the first panel at the first location to rotate the first panel relative to the lifting body, causing the second panel to translate along a guide path and rotate relative to the lifting body.