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Wings designed to minimize induced drag have a smooth distribution of lift from root to tip. Whether elliptical for span constrained wings or more bell shaped to minimize structural weight, ideal shapes do not have peaks and valleys.
However, when you take any shape and stick a prop in front of it, the distribution can change dramatically.
Do wing designers set lift distribution to be smooth before considering effects of the prop or after? Why?
Some wing designs incorporate the prop effect so much, that running the prop actually causes substantial airlift at zero airspeed. The channel wing is a good example, but not the only one.
Other designs are not much more than a bad glider with one or more engines stuck to it afterwards. Considering the effect of the prop on the wing in its design used to be a luxury until not too long ago. Other factors were more demanding and aerodynamics can be very forgiving.
Modern day aviation design does incorporate prop effect in wing design for two main reasons.
Firstly because it is possible and relatively easy to do so, thanks to a still rapidly expanding arsenal in aviation design software becoming available at ever more easily affordable prices.
Secondly, the introduction of electric flying allowing for the installation of very light and compact motors. This allows for the operation of a large number of motors powering an equally large number of props, capable of influencing pretty much all of the wing.
Another side effect of electric flying is the comparatively absurd power to weight ratio, expressed in something known as 'ludicrous mode'. In order to allow for cruising for extended time, an electric motor is needed that has a peak power output vastly greater than its cruising output. This too will have its effect on wing design.
The process may be a bit slower, but similar to the development in computers, eventually the development in aviation will not be determined by commerce or military, but by toys. Toys are ridiculously demanding and offer opportunity for testing concepts unheard of in aviation.
It appears that at least in this case wings are designed without regard to propwash and the subsequent inefficiency is ignored or at least tolerated.
it also changes the lift distribution of the wing from the ideal elliptical distribution to a more rollercoaster value created by the propeller streams. The result is that a well-designed wing and tail get their carefully tailored lift distribution destroyed by propeller/rotor streams...wings thus have lower L/D than their designers believe in their basic lift/drag analysis.
