Turbo-prop trainer aircraft are designed to offer a cost
effective alternative to military jet training aircraft. As
a design objective of such aircraft, the Military Specifications
of handling qualities applicable to jet trainer
aircraft should be satisfied. However, in line with the
philosophy of low purchase and maintenance costs, the added
complexity of a hydraulic power boost system for the control
surfaces cannot be accepted.
The objective of this work was to optimise the roll control
system so as to achieve an optimum of ergonomic design
combined with the performance goals of the military specifications, using purely aerodynamic means of
Relevant British and American civilian and military specifications
and simulator studies have been reviewed to select
the detailed design objectives of the study. The American
Mil. Specs. were selected as a baseline, with modifications
derived from the results of simulator experiments.
A Baseline Aircraft was selected on which to apply the
optimisation. The highest performance turbo-prop trainer of
the time was selected.
A mathematical model of the roll response was derived for
the extrapolation of flight test data and to allow an
evaluation and optimisation of the critical aileron
parameters. A description of the model and comparison to
flight test results is given in the text.
Literature was searched to examine the availability of
information for the aerodynamicist to conduct such an
optimisation. The results were disappointing, showing that
very little work had been conducted on aileron design since
the late 1940's and that the work of that time was not
entirely relevant to today's requirements. Because the
literature search was not conclusive, further flight tests
had to be conducted on the Baseline Aircraft to investigate
different forms of aerodynamic balance. The performance of
the ailerons and some of the problems encountered in their
usage are reported in this thesis and forms a data bank from
which to conduct the optimisation.
Finally, a selection process is conducted to size the
aileron to satisfy the performance goals and to select the
best aerodynamic balance to achieve the ergonomic goals.
The achieved performance is summarised and compared with the
original design goals. It is concluded that the optimised
aileron is capable of achieving the design goals over the
major portion of the design envelope.
The design optimisation process is not limited to turbo-prop
aircraft but can be applied to any high performance aircraft
with reversible controls.
A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy of Loughborough University.