Rerivet aileron ribs 2 and manufacture doubler

The aileron ribs2 were derivetted (right hand unit also derivetted from skin), with no hole-damage. However the front 2 or three holes of these ribs had previously had to be elongated due to a mismatch (partly but not entirely due to a hole centering error when originally enlarging the holes on hinge bracket 2). This elongation has previously treated with JB-Weld, but this was felt not to provide a satisfactory surface for a rivet tail to (in part) pull against. A decision was taken to manufacture a doubler plate from 0.81mm 6061-T6 to cover all 8 holes. This doubler plate would guarantee a solid surface for the rivet tail to pull against.

The mass of each doubler is 11 grams. Some thought was given to whether this would alter the dynamic/flutter characteristics of the aileron, but this possibility has been discounted due to several observations:

The mass of the aileron balance tube is 382g, subject to a tolerance of +/-47g based on typical wall thickness tolerances. This number is well in excess of the weight of this doubler, and has an even larger moment arm. The product moment of inertia due to the mass of the doubler is also thought insignificant owing to the magnitude of other uncontrolled variables.

No account is/needs to be taken of primer/paint mass.

The aileron centre of mass is actually 15mm aft of the hinge line, contrary to the expected forward position. TAF have confirmed that the ailerons do not need to be so closely balanced owing to the low flight speeds.