Sure,
So this plugin is probably on by default, but if not enable the ‘Modeling Tools Editor Mode’ plugin.
Then in the upper left of your screen, click the ‘Select Mode’ dropdown to go into modeling mode.
Under the ‘Transform’ section you will see “Pivot” tool.
What you are showing in your images with the single rectangular cube is expected behaviour. (With this technique you could have many individual meshes that fit together so long as all of their positions are “zeroed”) What you’re running into is trying to rotate your aileron around the origin/pivot.
So, changing the pivot in-engine should definitely get you where you want to be.
Let us know if you have more troubles with this!