Blade flutter has always been the downfall of the design. That is one reason carbon fiber’s rigidity may prove sufficient in this application.
No one has done much serious work with the Coanda effect recently. The back story is that Henry likely was the first jet jockey back in about 1928, when he crashed his prototype engine in a biplane.
He used a radial piston engine to drive a turbo-compressor supplying air to a cylindrical combustion chamber. An exhaust pipe exited this combustion chamber on each side of the fuselage. On a taxi test he lost focus on the aircraft velocity and position due to the fiery exhaust hugging the aircrafts flammable fabric skin—the test thus became a short flight to avoid a crash into a structure.
The extraordinary behavior of the exhaust gas flow diverted his focus from the engine development to flow dynamics, thus requiring another decade for development of a gas turbine engine.
Actually Henry Coanda built his aircraft in 1910.