An autogyro or Autogiro is a unique type of rotary-wing aircraft that was successfully flown in the 1920s, many years before the first helicopter came to service. As far as the rotorcraft technology is concerned, the technical issues addressed by autogyros were eventually rectified and paved the way for the success of helicopter development. When helicopter became more popular and accepted in the civil aviation industry in the 1940s, autogyros were nearly forgotten and the popularity slowly diminished. The re-emergence of autogyros in the last two decades in hobby and sports flight activities, however, coincides with bad safety records due to stability issues.At the time of this writing, there are no specific flying qualities standards to be em- ployed as guidelines to design a light autogyro with good stability attributes. The only requirements available are addressed in the BCAR Section T airworthiness standard for light autogyros which only prescribes some basic dynamic stability requirements for the vehicle. For existing conventional light autogyros which mostly of ‘home-built’ type, complying with the airworthiness standards would be an issue as most of them were built beforehand. From these concerns, this Thesis aims to improve the flying qualities performance of existing light autogyros through automatic flight control methods, as one of the ways to practically achieve the required performance. Consequently, specific flying qualities requirements for light autogyros must first be proposed as preliminary guidelines for design and flying qualities improvement. A generic mathematical model of light autogyros named ARDiS is developed based on the ‘multiblade’ simulation ap- proach which is computationally cost-effective. This model was successfully validated against real autogyro flight data and later implemented in the control enhancement of the vehicle.The control enhancement was developed using classical approaches with limitation in size and simplicity of the vehicle as a light aircraft. Proper actuation control hard- ware was separately modelled and deployed into the autogyro to demonstrate a higher dynamics in the control mechanism so that a more realistic attitude behaviour of the vehicle is presented. This control enhancement was successfully evaluated with both, linear and nonlinear simulations according to the proposed autogyro flying qualities attributes. All presented results signify a higher possibility of improving the flying qualities of currently used and future built light autogyros through control enhance- ment.
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Improved autogyro flying qualities using automatic control methods