sentences:  Cierva W.9
  
  The Cierva W.9 was a British 1940s experimental helicopter with a three-blade tilting-hub controlled main rotor, and torque compensation achieved using a jet of air discharged from the rear port side of the fuselage.In 1943, primary investor G & J Weir Ltd. revived the moribund Cierva Autogiro Company to develop an experimental helicopter to Air Ministry Specification E.16/43.