Strengthen quadcopters

[Franco malgarini]

strengthen quadcopters

Until you get to human flight,
with this device that increases the speed of the air flow:

Carl HALL -- Propeller Cowling -- Pop. Science, April 1933 -- USP #1961214

[wings]

strengthen quadcopters

Until you get to human flight,
with this device that increases the speed of the air flow:

Carl HALL -- Propeller Cowling -- Pop. Science, April 1933 -- USP #1961214

The effect of the non rotating parts is to recover the rotational energy of the fluid.
This is particularly important for the water, small advantages for the air.

Maritime Propulsion | VOITH’s New Propulsion System: The Voith Linear Jet (VLJ)
see
http://history.nasa.gov/SP-4219/Chapter14.html