Engine Airframe Integration Sensitivities for a STOL Commercial Aircraft Concept with Over-the-Wing Mounted UHBR-Turbofans

A transport aircraft concept featuring over-the-wing-mounted nacelles (OWN)positioned aft of the wing’s trailing edge is investigated with numerical methods. The objective of the study is to compare two different approaches for integrating the nacelle to the airframe from an aerodynamic point of view. On one hand, a pylon mounted OWN configuration is chosen for installing the propulsion system. On the other hand,a closer coupling between wing and nacelle by embedding the OWN into the wing is examined. Both configurations will be analysed at a representative reference position and discussed in terms of similarities and differences. Afterwards, a positioning study with a free flying nacelle is conducted to explore the aerodynamic sensitivities of wing and nacelle for this engine airframe integration position. The results show that a favourable position with the potential for drag reduction can be found