O.S. 25FX ABL w/Muffler

X-tra performance power for sport and competition!

O.S. FX Series Engines feature dual bearings for durability and smooth operation, plus a low crankcase profile that allows for a proportionately taller, semi-squared head — a refinement that increases cooling fin area and improves heat dispersion. Plus, you'll never worry about losing a prop during flight — the threaded portion of FX crankshafts is extra-long to promote better engagement of the prop, nut and spinner and greater flight safety. The high-speed needle valve on every FX engine is mounted remotely for added protection. An O-ring and ratchet spring minimize "creep" due to air leaks and vibration.
Displacement: 4.07cc (.2485 cu in) Bore: 18mm (.708") Stroke: 16mm (.630") Horsepower: .84 BHP at 18,000 rpm Weight: 248g (8.8oz) 10.8oz w/muffler Practical rpm Range: 2,500 - 19,000 rpm Recommended Props: Pattern Flying: 9x5, 9x6, Pattern Flying if a tuned pipe is used: 9.5x5 Sport Flying: 9x5, 9x6, 9.5x5, 10x4, 10x5

O.S. Engines two year limited warranty
  • All FX engines come with remote needle valve - the feature most asked for!
  • A longer crankshaft provides more secure attachment for spinner, prop and nut
  • Dual ball bearing construction adds durability and longevity
  • Semi-square head shape creates more fin area to increase cooling capacity
  • Each engine comes with a high-performance carburetor and muffler with adjustable exhaust direction and built-in pressure tap
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