8. Engine and aircraft integration

8.1 Aerodynamic interference

Propeller performance is often determined when the propeller is isolated (mounted on a shaft of infinite length, no cowling, no nacelle, no engine or wing air intake in its vicinity). When the propeller is installed on the aircraft, aerodynamic interactions occur (with the wing, the engine nacelle, the propeller spinner, etc.) which, in most cases, modify performance (up to ± 10% of propeller efficiency). Powerful numerical tools, still under development, are needed to correctly anticipate the consequences of these phenomena.

In addition, the propeller wake can sometimes have undesired effects on aircraft behavior...