Helicopters require a tail rotor to counteract the rotor torque; this and the articulated head complicate flying, construction and maintenance enormously.

需要直升机尾桨抵消转子力矩；这和阐述头复杂飞行，建造和维修极大。

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The rotor structure of claim 1, further comprising rotor head means including a ring bearing member for said rotor structure.

转子结构索赔1 ，进一步组成的转子头途径，包括一环轴承成员说，转子结构。

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Then we need to make the rotor head .

然后，我们需要使转子头。

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It included the black box flight recorder, the fuselage with the engines and rotor gearbox attached, the separated rotor head with the main rotor blades still attached, and the separated tail.

BBC: Crash report urges safety checks