A propeller has a high propulsive efficiency, yet inherently leaves the air it propels swirling. The efficiency of a propeller can be enhanced by placing it in the tip vortex of a wing. Such a tip-mounted propeller configuration lets the vortex created by the wing and the vortex created by the propeller counteract each other, enhancing the propulsive efficiency of the system. Even though the benefits of such a configuration are clear, the concept is not commercially viable. Among other benefits, electric engines are scalable, light and can be placed in advantageous positions. This allows the engine to be placed at the tip of a wing. The batteries for electric propulsion are heavy, so synergistic effects are needed to improve the efficiency to such an extent that electric propulsion will be commercially viable. Another benefit can be defined by tip-mounted propulsion. As the propeller is mounted at the tip of the wing, the moment arm is large. This could result in a large directional control moment. On the other hand, if one engine is inoperative, the resulting moment is so large that it cannot be compensated by a rudder deflection. Therefore, if a one-engine inoperative situation arises, to still produce thrust both propellers have to be interlinked resulting in a heavy system, or both engines should be switched off. If tip-mounted propellers are used to enhance directional stability and control, the vertical tailplane size can be reduced, resulting in a reduction of mass, drag and hence overall power consumption. In this thesis the contribution of tip-mounted propellers to static stability, dynamic stability, and control is researched, for both positive and negative input power. Negative input power denotes that the propellers are recuperating energy fromthe airflow, and is a state that is applicable when one engine is inoperable. The forces on a tip-mounted pusher propeller are obtained by linking a lifting line wing model and a combined blade-element momentum vortex propeller model. The lifting line model is used to calculate wing-induced velocities on the pusher propeller disk. These induced velocities are used as input for the propeller model, and a resulting thrust and power is obtained. These are corrected for an angle of attack on the propeller disk by empirical relations. The thrust, normal force and power are saved to a 7D dataset. A non-linear flight mechanics model of the Piper Seneca III uses the dataset as lookup table and implements the tip-mounted propeller as forces at the tip locations. Thrust variations in the 7D dataset are parametrically visualised, showing the expected trends. Resulting forces are compared with a rudder deflection, to estimate a potential rudder size reduction. When the aircraft is flying slow, tip-mounted propellers can match the maximum moment produced by the conventional rudder. When flying fast, around half the reference yawing moment can be produced by tip-mounted propellers. The static stability contribution of tip-mounted propellers is visualised parametrically for propeller diameter, advance ratio, blade pitch and a toe-in angle. Negative toe-in angles, hence toe-out angles, prove to greatly enhance the directional static stability. High thrust values greatly enhance longitudinal static stability as the reference aircraft’s wing tips are positioned above the centre of gravity. In the same parametric fashion as the static stability evaluation, the contribution of tip-mounted propellers to dynamic stability is evaluated. The damping factor and natural frequency are obtained for first order motions Dutch roll and the Phugoid by fitting an exponential curve to the time-response of the flight mechanicsmodel. This method succeeds in capturing the motion characteristics, and indicates clear trends: the frequency of the Dutch roll increases with toe-out angles and thrust, and the frequency increases with thrust. The Phugoid’s natural frequency increases with thrust, and damping factor decreases with thrust. An attempt is done to use the curve-fitting method for the second order motion Short period as well, yet proves too inaccurate. A typical tip-mounted propeller design is evaluated to summarise the effects of using tip-mounted propellers for directional stability and control. For this non-optimised design, the static stability is enhanced by 37%. The dynamic stability has increased significantly as well. Maximum blade pitch deflection and maximum rudder deflection result in similar time-history sideslip responses when the aircraft is flying slow, when flying fast the tip-mounted propeller design’s sideslip response is around half the reference rudder deflection response. This conclusion also applies to a one engine inoperative simulation. In this thesis, a significant first step is made toward enhancing directional stability and control with tip-mounted propellers by defining the contribution of tip-mounted propellers in a parametric fashion. The results are directly applicable to an aircraft that has been designed with tip-mounted propellers, yet does not rely on tip-mounted propellers for directional stability and control. A typical design is evaluated in cruise, recuperative and one-engine inoperative cases, proving that from a stability and control point of view the vertical tailplane can be reduced in size. Before tip-mounted propellers can be used for directional stability and control behaviour analysis in the stalled regime, more research has to be conducted. This is left as recommendation.