Did some fan-into-sail tests a while back. I put the motor pylon from one of my planes on a 3-wheeled cart, with a large foam plate at one end.
With the prop blowing at the plate, the cart would reluctantly move forward, the direction a plane would move with that setup.
Reversing the rotation with the prop blowing away from the plate, the cart would move rapidly in the opposite direction to the first configuration.
Not something many propellor people test for.