Out of stock

SKU: OS91FX/EG/NEA/RCA Category: Tag:

This is the OS Engines 91FX .61 ring glow engine, with 60f carburetor and included OS E4020 Muffler.  Designed for sport, but engineered for excellence, the 91FX offers the power and user-friendly features of other FX Series engines in a displacement fit for large-scale aircraft. The 91FX neatly bridges the power gap between .60-size glow engines and gas engines, by offering the easy familiarity of glow technology combined with the added power that today’s large-scale modelers demand. With its top output of 2.8 hp, the 91FX can put a large-scale plane through its paces with ease. And with O.S.’ meticulous testing and design behind it, large-scale pilots can fly the best in long-term dependability.


  • Multi-position remote-mounted needle valve design offers greater flexibility and safety for the pilot. The needle valve can be positioned upright or to the side to avoid cowl modifications and preserve scale looks.
  • Coarse threads and an O-ring seal on the needle valve minimize settings creep over time due to vibration and air leaks, providing more flights with fewer adjustments.
  • Extra-long crankshaft and locknut assembly offer more thread length for better prop nut engagement and more safety for pilots and onlookers.
  • A lower crankcase profile leaves room for more head height and cooling fins-semi-squared head design further enhances cooling capacity and performance.
  • Dual bearing design includes a larger front bearing for added durability and smoothness.
  • The ideal power plant for most Top Flite® Gold Edition Kits

Displacement: 0.912 cu in (15.0 cc)
Bore: 1.091 in (27.7 mm)
Stroke: 0.976 in (24.8 mm)
Practical rpm: 2,000-16,000
Output: 2.8 hp @ 15,000 rpm
Weight: 19.3 oz (550 g)
Recommended Props: 13×8, 13×9

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