See the following photos of the LH aileron of a Beechcraft King Air B200:
As seen in the above photos, the Beechcraft King Air B200 has what I would describe as a bulged trailing edge strip on both ailerons. These strips are roughly centered in the span of the aileron, and in the case of the LH aileron are located outboard of the trim tab.
In figure 57-50-00-06, the Beechcraft B200 IPC lists these as -320 and -325, calling them the LH and RH trailing edge strips:
The King Air 200 has the same trailing edge strips, which are listed as -70 in fig 57-70-10 of its IPC with the same part number as on the B200.
I do believe the King Air 300 series also has these strips, though I am not certain. I don't believe the King Air 90 has these, but again, I could be wrong.
I have asked many King Air pilots and maintenance crew if they knew what the purpose was, with no definite answer. The best answer I have recieved was a tentative suggestion that they might be for something like dampening control buffet.
Does anyone know the purpose for these bulged aileron trailing edge strips? Does anyone know of any documentation for their purpose? Do similar control surface design feature appear on other aircraft?