General Aviation VTOL
Thanks delta3,
Actually I am evaluating a proposed personal VTOL design in Kitplanes (June 1997) by an aero engineer Bill Welch.
He described a VTOL that looked similar to any small airplane but with six small fans installed inside the wings. A VTOL airplane.
He says that the small fans would not need all the heavy and complex hinges required for an open rotor helicopter and it could fly faster with the wing shutters closed.
It's an intriguing idea for its low cost and redundancy as you mentioned.
I think one rotor is probably always more efficient in pure aero terms. But when structural weight is included that is another matter.
slowrotor