67.The first successful helicopter flight was made in 1957.

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helicopter
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aircraft
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verticaltakeoff
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flight
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igorsikorsky
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rotor
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blade
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lift
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hover
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maneuver
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aviation
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innovation
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technology
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design
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prototype
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testflight
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control
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stability
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navigation
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cockpit
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instrumentation
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altitude
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speed
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range
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payload
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military
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civilian
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rescue
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transport
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popularity