| Wright J-6 Whirlwind
 
      Like the J-5, 
      the J-6 Whirlwind was based on the J-4 of 1924, this time with cylinders 
      of increased bore (from 4.5 to 5 inches). The first J-6 (the Whirlwind 7) flew in 1925. In 1929, the Whirlwind 9 was 
      introduced and in 1930, the Whirlwind 5. All three shared the same 
      cylinder design (5 x 5.5 in); they differed in the number of cylinders.
 
 The Whirlwind 9 (R-975) was also produced by Continental during World War 
      II.
 
      
      models 
        J-6 Whirlwind (R-540): 165-175 hp (123-131 kW) J-6 Whirlwind 7 (R-760): 225-320 hp (168-238 kW)
        J-6 Whirlwind 9 (R-975): 300-420 hp (223-313 kW)
         specifications 
      Whirlwind 5 (R-540) Whirlwind 7 (R-760) Whirlwind 9 (R-975) used by 
        Bellanca CH-300 Pacemaker Curtiss Robin Curtiss-Wright CW-22 Falcon Ford C-9 Trimotor Lockheed R3O Vultee BT-15 Valiant  |