The video notes that when printing 4 props, 2 must be reversed in the Y-axis to print a counter-rotating set of 4. The instructions used for creating propellers in Fusion3D are available here.

This is more of a hybrid affair, with counter-rotating props mounted in a centrally located duct providing the lift and the yaw control. Flanking that is a triangular frame supporting three two ...

Gladding-Hearn Shipbuilding, Duclos Corporation has delivered a repowered pilot boat, after 10 years of continuous service ...

The aircraft’s performance was due in part to the giant, counter-rotating propellers, says Bowers. “When you start blowing that amount of air with that amount of power over a fairly large wing ...