title: Walter Mars I
text: # Walter Mars I
  
  The Walter Mars I was a nine-cylinder, air-cooled, radial engine for aircraft use built in Czechoslovakia in the late 1920s.
  
  ## Design and development
  
  The Mars I was the largest capacity design of a series of three similar radial engines developed by the Walter company. Common cylinders were used for the five-cylinder Walter Vega and the seven-cylinder Walter Venus, the Mars I being a nine-cylinder engine.
  
  ## Applications
  
  * ANBO III
  * Breda Ba.15
  * DAR 4
  * DAR 6
  * Fizir FN
  * Focke-Wulf A 33
  * Letov Š-32
  * SET 10
  
  ## Specifications
  
  Data from Flight, July 1929.
  
  ### General characteristics
  
  * Type: 9-cylinder radial engine
  * Bore: 105 mm (5.90 in)
  * Stroke: 120 mm (4.72 in)
  * Displacement: 9.352 L (570.7 cu in)
  * Dry weight: 159 kg (350 lb)
  
  ### Components
  
  * Fuel system: Zenith Type 42 carburettor; two plugs/cylinder and twin Scintilla magnetos
  * Cooling system: Air-cooled
  * Reduction gear: Direct drive
  
  ### Performance
  
  * Power output: 112 kW (150 hp)
  * Compression ratio: 5.15:1
  * Power-to-weight ratio: 0.72 kW/kg (0.43 hp/lb)
  