Graviman
12th Oct 2006, 19:19
The arguement always goes like this:
Teetering rotors only need to be designed to take lift force, and not any cyclic control moments. The head and rotor shaft only needs to react lift and not bending moments. Since no bending moments are imparted into the rotor shaft bearings and structure can be smaller. This all saves cost and weight, so the helicopter is cheaper to build and to run.
I am assuming that the cyclic control system has been modified to make a rigid rotor at least as easy to fly as a teetering rotor. My arguement is that the structure has ultimately to be designed to handle pitch and roll control moments anyway, so can be extended close to the rotor head. The rotor shaft bearing can then be put nearer the rotor head reducing the rotor shaft forces. This means that only the blades need to react additional bending moments, but are ideally stiff anyway to avoid aeroflexure.
The industry seems to be moving across to rigid rotors, so are the advantages of teetering more myth now than fact? This is a genuine question.
Mart
Teetering rotors only need to be designed to take lift force, and not any cyclic control moments. The head and rotor shaft only needs to react lift and not bending moments. Since no bending moments are imparted into the rotor shaft bearings and structure can be smaller. This all saves cost and weight, so the helicopter is cheaper to build and to run.
I am assuming that the cyclic control system has been modified to make a rigid rotor at least as easy to fly as a teetering rotor. My arguement is that the structure has ultimately to be designed to handle pitch and roll control moments anyway, so can be extended close to the rotor head. The rotor shaft bearing can then be put nearer the rotor head reducing the rotor shaft forces. This means that only the blades need to react additional bending moments, but are ideally stiff anyway to avoid aeroflexure.
The industry seems to be moving across to rigid rotors, so are the advantages of teetering more myth now than fact? This is a genuine question.
Mart