OS Engines FSa-72 II Four Stroke Aircraft Engine w/ F-5030 Silencer

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  • The adjustable F5030 muffler can be rotated 360° and moved in or out for a perfect fit. Rich, deep sound is an added benefit.
  • Features the same mounting bolt pattern as the FL70 and the FS70 Ultimate for easy replacement.
  • A reversible carb and narrower camshaft housing simplify installation.
  • Tighter tolerances and updated engineering reduce maintenance and ease setup.
  • Delivers more performance power to sport pilots and more realistic flight to scale pilots.
  • Blowby oil exits through the breather nipple on back plate for more stable operation
  • Black rocker covers
  • 61N aluminum body carburetor with rotary throttle lever, high speed needle valve, and low speed mixture control, extended intake tube eliminates reverse flow tendency of air/fuel mixture, carb is reversible 180°
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OS Engines FSa-72 II Four Stroke Aircraft Engine w/ F-5030 Silencer

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Product Information

O.S. leads the way in advanced 4-stroke engine technology, and you’ll see for yourself when you mount the FSa-72II in your model! Sport flyers will enjoy greater performance, while scale pilots will experience more realistic flight. Plus, everyone will benefit from the FSa-72II’s deep, rich sound.


0.719 cu in (11.79cc)
1.063" (20.7mm)
0.811" (20.6mm)
Max Power
1.2PS/12,000 RPM, 1.18HP/12,000 RPM
Engine Weight
16.79oz (476g)
Silencer Weight
1.9oz (54g)
Practical RPM
2,400 - 12,500
Crankshaft Thread Size
1/4 x 28
Height from Bottom of Mounting Tab/Top of Rocker Cover
3.5" (90mm)
Height bottom of Crankcase/top of Rocker Cover
4.2" (108mm)
Width of Crankcase below Mounting Tabs
1.4" (36mm)
Distance from Drive Washer to Rear of Carburetor
4.1" (103.6mm)
Centre of Mounting Holes Same Side
0.79" (20mm)
Centre of Mounting Holes Opposite Side
1.8" (45mm)
Centre of Front Mounting Hole to Drive Washer
1.9" (49.5mm)
Centre of Rear Mounting Hole to Drive Washer
2.7" (69.5mm)
Centre of Crankcase to Center of Needle Assembly
1.3" (33.7mm)
Muffler Angle in Relation to Engine
Needle Settings
High Speed2.5 - 3 turns out from fully closed
Mixture Control (low speed)
2 turns out from fully closed