The class of aircraft known as gyroplanes (or autogyros) helped to pave the way for the development of the helicopter. However, they have found no application in contemporary commercial or military aviation. It is in recreational or sport flying that the gyroplane has proved popular. Most if not all designs are however homebuilts, and as a consequence little analysis of any significance has been conducted on the flight mechanics of these aircraft. This Paper presents an analysis of the longitudinal stability of gyroplanes. Simple consideration of the basic forces and moments that might influence stability, in the context of elementary rotor behaviour, is used to assess the fundamental nature of gyroplane longitudinal stability. This is quantified by the application of a sophisticated generic rotorcraft mathematical model to the gyroplane problem. It is concluded that the basic configuration can be longitudinally stable with appropriate design, and that the rotorspeed degree of freedom must also be included when modelling the aircraft.

A novel automatic grid generation method for complex CFD applications has been developed, driven by the need of the industrial CFD practitioner to reduce the turnaround time from an initial CAD geometry to obtaining a flow simulation. The method uses a subdivision strategy, allowing hanging nodes in a Cartesian unstructured mesh environment and is combined with a non-overlapping, semi-structured surface grid. Unusually, the surface grid is the end rather than the starting point of the present approach. This reversal of gridding strategy allows usability to be enhanced, in that the grid generation is reduced to one automatic step. The capabilities of the method are demonstrated by reference to selected inviscid and viscous flow solutions using the Fluent code Rampant v4.0 as a flow solver.

Steady, inviscid, incompressible, two dimensional flows containing vortex patches bounded by vortex sheets are used to model finite separated regions on certain closed bodies as an approach to modelling separation bubbles. First of all the problem of a vortex patch on a circle is considered. Calculations were done for symmetric flows covering a wide range of values of the separation position, the strength of the vortex sheet and the circulation at infinity and for non-symmetric flows at various angles of incidence. Smooth separation was detected in some cases. This model is used as an intermediate step for the calculation of the flow around an ellipse and a Joukowski aerofoil with the use of the Joukowski transformation.

During recent years a new vortex model of the unsteady aerodynamics of a hovering rotor or a rotor in axial flight, named Temura, has been developed in the Technion. This model has succeeded in describing various phenomena of rotor dynamics. In the present paper Temura is used in order to develop a model which describes the blades’ responses to harmonic variations of their pitch angles. This model includes unsteady influences of trailing and shed vortices, together with unsteady geometric effects which represent a special capability of Temura. The model is general and can be applied to any number of blades and arbitrary differences between the pitch angle variations of different blades. The application of the model to analyse cases of collective harmonic pitch variations and differential harmonic pitch variations is presented. Numerical results of the new model are compared with experimental results from the literature and good agreement is shown.