O.S. Engines 155FS 4-stroke

O.S. Engines 155FS 4-stroke


Looking for a compact engine to fit in your scale aircraft’s cowl? This 4-stroke might be the right answer: it offers the power of a larger, 2.00-size engine but is the same size and weight as most 1.20-size 4-strokes!

Here’s the press release, direct from O.S. Engines:

The O.S.® Engines 155FS-a 4-stroke engine is designed to give more power from a smaller package.  The 155FS-a produces 2.6 horsepower – about the same as many 200-size power plants – from a package that’s about the same size and weight as most 120-sizw engines!  Fewer modifications and easier retrofits leave you with more time to enjoy the added performance.  And since the 155FS-a is a pumped 4-stroke, you’ll be able to enjoy improved performance consistently – regardless of model attitude, fuel levels or tank position.  All of this with easier maintenance – and less of it!  Instead of venting oil through a crankcase tube, the 155FS-a recirculates it which improves lubrication of the working parts and prevents oil from getting all over the cowl.  Any way you look at it, the 155FS-a is a great choice for giant-scale modeling.


Displacement: 25.36cc (1.548 cu in)

Bore: 33.6 mm (1.323 in)

Stroke: 28.6 mm (1.126 in)

Practical RPM Range: 2,000 – 10,000 rpm

Output: 2.6ps/10,000 rpm

Weight: 1.775 lbs (805.0 g)


The 155FS-a 4-stroke engine is available late Fe

Updated: July 16, 2015 — 10:26 AM
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