DeltaV wrote:Here's a screwball idea for high-voltage lift fans:
Hollow fan blades with slotted trailing edges, E-APE interiors (fed by air from the hub, which also provides HV and commutates the ionization laser) and airfoil exteriors. Conductive outer duct or a connected, rotating conductive ring to complete the circuit across a small gap to ground. It would need large blades (the best ones have a 'wavy' outer surface), so limited to low speeds.
Now, there is a way to curve the arcs (and in some cases, make them self-healing). That means the hollow fan blades can be smaller (higher rotational and vehicle speeds...)
Laser-assisted guiding of electric discharges around objects
For reference, here is a modern turbofan's business end, which would require a 3D (space curve) arc path (thus, phase mask generated Airy beams from each end) and varying elliptical (internal) sections along the blade length:
Due to blade twist and internal cross section area variation, the axial and tangential (apart from linear change in radial lever arm) contributions to the thrust vector and fan disk angular momentum by the shock waves leaving the curved exit slot would vary along the blade length. The outer sections have narrower ellipses and would converge the shock waves faster, while the sections near the blade roots would have fatter ellipses but also a smaller separation of foci, so it's not immediately obvious how the exhausted shock pulse would evolve in time.