I'm trying to figure out how to handle the control surface tip geometry for surfaces with a slightly swept hinge line (<15°).
It seems like there are two options:
1) Cut off the surface tip perpendicular to the spar.
2) Cut off the surface tip with a conical surface formed by revolving an approximately longitudinal control line around the hinge line.
(Does that make sense? I can illustrate if needed.)
(1) is simpler, and it avoids odd geometry. The problem with (1) is that, for control surfaces that have deflection during cruise flight (elevators, elevons) they present a cut-off surface at an angle to the free stream, presumedly adding drag. Using the cone from (2), you can have the cut-off be approximately in the free stream direction.
What do existing designs do? I'm leaning towards (2) since my cruise control surface deflection can be up to 2.5°, which is actually a pretty high amount of base area presented to the wind; but I'd love some inspiration on how the somewhat strange geometry that comes from this approach is handled.
It seems like there are two options:
1) Cut off the surface tip perpendicular to the spar.
2) Cut off the surface tip with a conical surface formed by revolving an approximately longitudinal control line around the hinge line.
(Does that make sense? I can illustrate if needed.)
(1) is simpler, and it avoids odd geometry. The problem with (1) is that, for control surfaces that have deflection during cruise flight (elevators, elevons) they present a cut-off surface at an angle to the free stream, presumedly adding drag. Using the cone from (2), you can have the cut-off be approximately in the free stream direction.
What do existing designs do? I'm leaning towards (2) since my cruise control surface deflection can be up to 2.5°, which is actually a pretty high amount of base area presented to the wind; but I'd love some inspiration on how the somewhat strange geometry that comes from this approach is handled.
