OSM34721 O.S. ENGINES FSa-72II Airplane Engine w/F-5030 Silencer

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OSM34721 O.S. ENGINES FSa-72II Airplane Engine w/F-5030 Silencer

Note: Graves RC Coupons are not applicable with this product  


The Tradition Continues...

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.
  • The adjustable F-5030 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 FL-70 and the FS-70 Ultimate for easy replacement.
  • A reversible carb and narrower camshaft housing simplify installation.
  • Tighter tolerances and updated engineering reduce maintenance and ease set-up.
  • Delivers more performance power to sport pilots and more realistic flight to scale pilots.
Notes from our tech department:
This is the O.S. Engines FSA-72II Engine with the F-5030 Silencer.





Blow-by 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°
Adjustable F-5030 muffler for quiet operation can be rotated 360°
for tight fitting applications
Two-year limited warranty through Hobby Services beginning at date of




O.S. Engines FSA-72II Engine, F-5030 Silencer, Type F Glow Plug and




Fuel: 10%-20% nitromethane with 18% lubricant. Synthetic, castor, or
a synthetic/castor lubricant blend may be used.
NOTE: Certain four-cycle fuels cannot be used due to low oil content
However, SOME four-cycle fuels such as the Wildcat 4-Cycle 15%
may be used due to its 18% oil content.
When choosing fuels for this engine, be sure to select a fuel with
at least an 18% lubricant content.
Propeller: Sport & Aerobatic 12x7-8, 13x6-8
Scale 14x6-7




Displacement: 0.719 cu in (11.79cc)
Bore: 1.063" (20.7mm)
Stroke: 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)
Center of Mounting Holes Same Side: 0.79" (20mm)
Center of Mounting Holes Opposite Side: 1.8" (45mm)
Center of Front Mounting Hole to Drive Washer: 1.9" (49.5mm)
Center of Rear Mounting Hole to Drive Washer: 2.7" (69.5mm)
Center of Crankcase to Center of Needle Assembly: 1.3" (33.7mm)
Muffler Angle in Relation to Engine: 11°
Needle Settings: High Speed: 2.5 - 3 turns out from fully closed
Mixture Control (low speed): 2 turns out from fully




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Additional Information

0.60 ci (9.8cc) to 0.89 ci (14.6cc)
Parts & Accessories:
Nitro (4-Stroke)
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