Generally, the propeller wash from a front-mounted propeller tends to increase the lift relative to a center or rear propeller in certain flight conditions. Here are the reasons why:
1. Slipstream Effect: The propeller generates a slipstream of accelerated air behind it. As the propeller rotates, it pushes air backwards, creating a high-speed airflow. This slipstream can interact with the wing and increase its effective angle of attack. As the angle of attack increases, the lift generated by the wing also increases.
2. Increased Boundary Layer Energy: The propeller wash can energize the boundary layer over the wing. The boundary layer is the layer of air that flows over the wing's surface. When the propeller wash interacts with the boundary layer, it helps to keep it attached to the wing for a longer duration, reducing the chances of flow separation. This results in improved lift generation and reduced drag.
3. Propeller-Induced Downwash: The rotation of the propeller also creates a downwash, which is a downward flow of air. This downwash can have a beneficial effect on the lift distribution across the wing. It can help to increase the pressure on the upper surface of the wing and decrease the pressure on the lower surface, resulting in an overall increase in lift.
However, it's important to note that the effects of propeller wash can vary depending on the specific design of the aircraft and its operating conditions. In certain cases, the propeller wash from a center or rear propeller may also contribute to lift generation, depending on the placement and design of the propellers.
