How does combining trim tabs and anti-servo tabs on a single surface work? It seems that naïvely, a surface with two separate such tabs would have difficulty trimming.
Conceptually my problem is that we know that a downward-deflected elevator is going to try to move back upwards without tabs. An anti-servo tab will exacerbate this tendency. To trim it, then, the net force applied by all the tabs must be significantly downards; so if the trim tab has 1/4th the area of the anti-servo tab, its deflection will probably be 4x higher. If tab deflections are limited to 40°*(a lot!) relative to the surface, we're looking at a < 10°*limit for the anti-servo tab, which is not a whole lot. Does this make sense?
It seems like an alternative is to have the anti-servo tab continue to have a fixed gear ratio to the control surface deflection, but have the trim system modify the zero point (alignment) of the anti-servo tab, rather than being an independent surface. Has this been done? Would it work?
Conceptually my problem is that we know that a downward-deflected elevator is going to try to move back upwards without tabs. An anti-servo tab will exacerbate this tendency. To trim it, then, the net force applied by all the tabs must be significantly downards; so if the trim tab has 1/4th the area of the anti-servo tab, its deflection will probably be 4x higher. If tab deflections are limited to 40°*(a lot!) relative to the surface, we're looking at a < 10°*limit for the anti-servo tab, which is not a whole lot. Does this make sense?
It seems like an alternative is to have the anti-servo tab continue to have a fixed gear ratio to the control surface deflection, but have the trim system modify the zero point (alignment) of the anti-servo tab, rather than being an independent surface. Has this been done? Would it work?
