Valach by Fiala FM 420 R5 with electric fuel pump


Fiala, the manufacturers of the Valach engines, are a company that caters to the military; hence this is military grade equipment under constant development, it is and always will the most advanced engine manufacturer on the market.

At the moment we carry over 20 different models of Fiala engines.

Please contact for customized and lower shipping rates for shipping outside the US.

Valach by Fiala 420cc R5 radial gas 4stroke engine with electronic ignition and electric fuel pump incuded - This motor has been designed from the ground up for fuel pump usage, the Fiala/APS fuel pump is already included (US$245 value).


  • Cylinder:  5
  • Displacement:  420 cc
  • Output:  ca. 25 hp
  • Bore:  47 mm
  • Stroke:  48.5 mm
  • Diameter:  425 mm
  • Length from engine mount to prop hub:  255 mm
  • Weight:  11.8 kg
  • Ignition voltage range:  6 - 9 V
  • Idle RPM:  800
  • Max RPM:  4500


Click for Dimensions


Fiala is the only 4-stroke company in the world which produces both the engines and the propellers developed and designed to be used with them. They go hand in hand.

The Fiala propellers have quickly become a staple in the global UAV industry as no other propeller matches their efficiency.

Hence it is important to run the Fiala propellers with the Fiala engines should you want to run the diameters and pitches shown in the Fiala manual. These specifications are based only, and I cannot stress that enough, on their purpose designed and built Fiala propellers.

Other brands run the risk of over torquing and stressing the engine unnecessarily, limiting performance and service life.


Recommended props:

40 x 20 Fiala 2blade

42 x 20 Fiala 2blade