title: Avia 51
text: # Avia 51
  
  The Avia 51 was a 1930s Czechoslovakian six-passenger commercial transport, designed by Robert Nebesář and built by Avia. The type was uneconomical in use and only three were built.
  
  ## Development
  
  The Avia 51 was a three-engined high-wing cantilever monoplane designed for the Czech national airlines CLS. It was built with a duraluminium monocoque fuselage and a fixed tailwheel landing gear. Powered by three Avia Rk.12 radial engines, two were fitted into the leading edges of the wing and one was nose-mounted. It had a two-man flight deck and an enclosed luxury cabin for five or six passengers which was not large enough to stand up (5 ft 1in), but did have a separate lavatory compartment, it also had three luggage and mail compartments.
  
  ## Operational history
  
  The Avia 51 entered service on the Berlin-Prague-Vienna route, but with only a small passenger capacity it proved uneconomical to operate. In 1937 the aircraft were sold to the Estonian government One appeared operating for the Spanish Republican Air Force in the Spanish Civil War, and it was reported that the other two were lost at sea when the freighter carrying them to Bilbao was sunk.
  
  ## Operators
  
  ### Spain
  
  * Spanish Republican Air Force
  
  ## Specifications
  
  Data from
  
  General characteristics
  
  * Crew: two
  * Capacity: six
  * Length: 10.75 m (35 ft 3 in)
  * Wingspan: 15.10 m (49 ft 6 in)
  * Height: 3.50 m (11 ft 6 in)
  * Wing area: 38.00 $m^2$ (409.0 sq ft)
  * Empty weight: 2,990 kg (6,592 lb)
  * Max takeoff weight: 3,750 kg (8,267 lb)
  * Powerplant: 3 × Avia Rk.12 7-cylinder air-cooled radial engine, 150 kW (200 hp) each
  
  Performance
  
  * Maximum speed: 264 km/h (164 mph, 143 kn)
  * Cruise speed: 230 km/h (140 mph, 120 kn)
  * Range: 780 km (480 mi, 420 nmi)
  * Service ceiling: 4,000 m (13,000 ft)
  * Rate of climb: 4.2 m/s (820 ft/min)
  * Lift-to-drag: 10.2
  * Wing loading: 94 $kg/m^2$ (19.3 lb/sq ft)
  