“how does a conventional aircraft’s tailplane actually work ?”
The horizontal stabliziers (the little “wings”) help the airplane resist pitch, which is an up and down rotation about a side to side axis.
The rudder is a movable panel at the rear of the tail, and it lets the pilot adjust the yaw of the airplane relative to the airstream. Note that this isn’t really used to steer, which is done instead by banking the aircraft to one side and pulling the nose up somewhat.
The elevators are movable panels at the rear edges of the horizontal stabilizers, and are moved to adjust the angle of attack (how much the nose is pointed up or down relative to the airstream).
More or less.
Do the "trim tabs" help the pilot fine-tune this function?
Interesting answers !
Point is, in conventionally-configured aircraft (like -51 platform) the “horizontal stabilizer” (to give its correct name ) “flies down” ! That is it applies force in 180’ opposition to the aerodynamic forces from the main plain, (i.e. wing) ! Suddenly remove this force and the aircraft “pitches over “ i.e. noses “down” from the pilot’s viewpoint.
IOW, some conclusions/suppositions I’ve read, here and elswhere, claiming the “tail failure caused the pitch up” are, IMO, pretty much false to known fact. Loss of the trim tab might - indeed probably - increased stick pitch forces but not - IMNSHO - to the point of causing a LOC. (I know I’d configure the aircraft W/B and consummable loads consumption CG changes to create/maintain a neutral or aft limit CG in order to minimize “trim drag”.)
Want a real world description of what a “tail loss stall” is ? Read Bob Cardenas’ description of his first stall in the first Northrup flying wing ! It had no tail ! >PS