The key thing needed in order for the proof of concept to sustain motion is power amplification. If one comes to sincerely believe power amplification is possible, they should have no problem in believing the proof of concept prototype could work because the only unique thing in the proof of concept prototype is the power amplifier. All the other components are conventional, well-known and well-proven.
The power amplifier is illustrated below. The input is X watts of electrical power and the output is Y watts of mechanical power. The hope is that we can design this power amplifier so that Y is significantly greater than X. The gain in power would be achieved by spinning airfoils that have a high Lift to Drag ratio which create torque on a rotating beam connected to the output shaft. This idea needs to be well-proven and verified because probably all engineering and technical people will claim it is impossible.
An alternative configuration of the power amplifier is shown below.
The power amplifier is one very large MOTOR as illustrated below. The motors, airfoils, beam and shaft are the rotor of the MOTOR.
One could argue that the above MOTOR is equivalent to a gearbox and therefore cannot amplify power since for an ideal, lossless gearbox the torque multiplied by RPM is constant, and if the torque at the output is increased, the RPM must decrease, but the MOTOR is not equivalent to a gearbox because the output RPM is not determined by a gear ratio. There does not appear to be any way to predict what the output RPM will be without building a proof of concept prototype.