Co-axial counter-rotating propellers are an interesting mechanical and aerodynamic problem with many complexities.
Normally they are only used when absolutely necessary, for example, to harness the full power of a large engine. The Russian Bear bomber comes to mind. The reasons to avoid, I...
RE the A300 Accident: I wanted to add a caution about taking the Aviation Week aero data or the NTSB releases at face value. The claim by both sources is that ultimate structural loads can be exceeded by combinations of aircraft sideslip and rudder movements that do not exceed the deflection...
