Assessment of a Slotted, Natural-Laminar-Flow Airfoil for Advanced Air Mobility Applications

The advanced air mobility (AAM) sector is using novel aircraft configurations and distributed electric propulsion to revolutionize aviation. These concepts require rotors that are efficient in vertical and forward flight. A concept that shows potential for this application is the slotted, natural-laminar-flow (SNLF) airfoil due to its high lift and low drag characteristics. This work explores the impacts of using an SNLF airfoil on an AAM rotor. Comparisons are made with blade element momentum theory (BEMT) method and computational fluid dynamics (CFD) to study the impact on the performance of an isolated rotor in hover. It is found that the rotational speed of the SNLF rotor can be reduced by 8% while still maintaining the necessary thrust for trim. A rotor broadband noise prediction shows that the slower SNLF rotor is 1-2dB quieter in terms of overall sound pressure level. Comparison of both rotors in forward flight indicates that the SNLF rotor consistently has a 1-2% higher propeller efficiency.