[srinath27182]

Hi

It is a view held by many that Propeller shrouds increase static thrust. Is this true?
If so why and what design criteria should the shroud meet ?

We all know that when a propeller is brought close to the ground, it experiences an increase in lift.
If we placed a plate directly under the propeller, would the plate+propeller combination experience a net change in thrust?
What if the plate were spinning (and pushing the air outwards--think flow past a spinning disk, that should reduce the pressure build up over the plate)