A dissertation submitted to the Faculty of Engineering and the Built Environment, University of
the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of
Science in Engineering.
Johannesburg, July-2015The objective of this research was twofold. The first objective was for the design and testing of
a compact force measurement device, capable of fitting inside the wind tunnel model and
measuring aileron hinge moments. Using the hinge moment balance, the second objective was
to test the effect of varying the trailing edge thickness of the aileron. A plain type aileron, with
a 20.6% chord and 40% span, was attached to a NACA 0012 wing. Four aileron test pieces
with trailing edge thicknesses from 0.39%c to 1.22%c were used. A external balance capable of
measuring the wing rolling and yawing moments was used in conjunction with the hinge
moment balance. Validation of the results and performance of the hinge moment balance was
done by comparisons to the data obtained from previous research and investigations using flow
visualization. The results indicated that the system performed in a manner that was expected
and predictable. The data from the hinge moment balance had an uncertainty of 4.2% which
was deemed satisfactory for the purposes of this research. For the majority of the test cases the
effects of the varied trailing edge thickness was found to be negligible. Small differences were
noted at high angles of attack, above 15°, and high aileron deflections, above 20°. As these
conditions were seen to be outside the typical flight envelope of general aviation aircraft, these
small differences were seen as inconsequential. It was concluded that the use of an aileron with
a thicker trailing edge would not have a negative effect on the performance of the aileron while
allowing for less restrictions on the manufacture of the aileron itself