title: Barnett J4B
text: # Barnett J4B
  
  The Barnett J4B is a small gyroplane marketed in the United States by Barnett Rotorcraft for homebuilding. Originally flown as the J-3M with an open cockpit and fabric-covered sides, later versions have a fiberglass cockpit pod either partially or fully enclosing the pilot. Apart from the basic J4B, versions available in 2007 included the BRC540 (two seats side-by-side) and J4B2 (two seats in tandem).
  
  ## Variants
  
  ### J-3M
  
      Original variant with 48.5 kW (65.0 hp) Continental A65 engine.
  
  ### J-4M
  
      Improved J-3M with 63.5 kW (85.2 hp) Continental C85 engine.
  
  ### J4B
  
      Single-seat autogyro with 23 ft rotor.
  
  ### J4B-2
  
      Two-seat variant of the J4B with a 25ft 4in rotor.
  
  ## Specifications (typical J4B)
  
  General characteristics
  
  * Crew: one pilot
  * Length: 12 ft 4 in (3.76 m)
  * Height: 7 ft 8 in (2.34 m)
  * Empty weight: 530 lb (240 kg)
  * Gross weight: 880 lb (400 kg)
  * Powerplant: 1 × Continental O-200 , 100 hp (75 kW)
  * Main rotor diameter: 23 ft 0 in (6.10 m)
  * Main rotor area: 314 sq ft (29.2 $m^2)$
  
  Performance
  
  * Maximum speed: 125 mph (200 km/h, 109 kn)
  