Here’s a NASA paper on the propeller arrangement: https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20160010105.pdf https://ntrs.nasa.gov/archive/nasa/casi

Here’s a NASA paper on the propeller arrangement: https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20160010105.pdf https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/201600... Apparently the small propellers’ primary function is “to act as a high-lift device [1]” rather than to generate thrust. They allow the wings to have a higher aspect ratio (i.e., be ‘long and skinny’) for reduced drag. Without them, such a wing would give undesirable low-speed handling characteristics and a higher stall speed. Also, their speed can be varied independently and quickly by computer to compensate for turbulence and wind gusts. Looks like quite an interesting design that plays to the strengths of electric motors. [1]: https://en.wikipedia.org/wiki/High-lift_device https://en.wikipedia.org/wiki/High-lift_device