Impact of the aileron gap sealing on the aileron effectiveness

Purpose The purpose of the presented aileron modification analysis is the improvement of the flight handling by eliminating adverse phenomena in the aileron area, such as aileron shaking movements, without the risk of deterioration of flow characteristics during manoeuvres. It was also crucial to reduce aileron forces acting on the control stick. Design/methodology/approach Numerical CFD analysis of the aileron system with modifications of sealing in the aileron gap area were performed. The effect of the caulking strip at the upper surface of the aileron gap was determined, as well as caulking at the entrance to the aileron gap on the bottom surface. A solution has also been proposed, consisting of completely closing the aileron gap by using a diaphragm. The three-dimensional flow analysis was carried out, allowing localization of the flow disturbances in the aileron gap at cruising speed. The result of the analysis are the aerodynamic and the hinge moment coefficients determining forces on the control stick, depending on the type of seals. Findings It has been shown that the use of subsequent sealing means has a direct impact on the hinge moment value. The results of the CFD analysis showed that the more closed aileron gap is, the higher aileron forces are generated on the control stick. Completely closing the flow in the aileron gap changes the character of the force generated on the control stick. Practical implications Through CFD analyses of the aileron gap sealing in the PZL-130 Orlik aircraft, the impact of successive aileron gap sealing on the aileron efficiency was determined. It has been shown that simple change of the aileron gap size by the slat sealing can significantly affect the value of the forces generated on the control stick. Originality/value The research using CFD methods allowed to verify the impact of the particular type of aileron gap sealing on the hinge moment value and thus to determine proper sealing configuration for the PZL-130 Orlik aircraft at low computational cost.