O.S. FS30 Surpass w/F-1020 Silencer (L-OS33000) The smallest in the O.S. four stroke range &, at only 9.56 oz, its also the worlds lightest production model four stroke. It has most of the features of the larger single cylinder O.S. four strokes, but it has its camshaft carried in bronze bushes
- backed up by a pair of spherical thrust bearings. Ideal for trainers, scale & sport models. Designed to be used with 9” x 6~7” to 10” x 6” props. Specification: Weight: 279g Propeller Range: 9x 6-7 10x 4 Displacement: 4.89cc 0.299cu. In. Bore: 19.5mm 0.767in. Stroke: 16.4mm 0.648in Practical RPM: 2500-13000
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O.S. FS40 Surpass w/FS40S Silencer (L-OS35220) The original 6.5cc FS-40 was O.S.s second production single cylinder four stroke & the first to have the front mounted helical driven camshaft now common to all their single cylinder O.S. four stroke engines. The current FS-40S is an all-new design which is much more powerful & closely related to the FS-48, though smaller both internally & externally. Supplied complete with silencer, the FS-40S is ideal for sport & scale models & is designed for use with 10” x 7.5” to 12” x 6” propellers. Specification: Weight: 355g 12.52oz Propeller Range: 10x 7-7.5 11x 6 11x 7 12x 5-6 Displacement: 6.49cc 0.40cc. In. Bore: 21.20mm 0.835in. Stroke: 18.4mm 0.724in Power Output: 0.65PS@12000RPM Practical RPM: 2200-12000 ...

O.S. FSa-110 w/F-5040 Silencer (L-OS35410) Designed specifically to offer more power & torque compared to a. 91 size four stroke, yet still fit in the same mounting

Dimensions, the FSa-110 is a real compact powerhouse. Like all FSa series engines, the FSa-110 has near perfect carburation across the RPM range, & thanks to the carefully designed exhaust, a soft yet authoritive note to minimise your presence to the neighbours. Precision carburation, internal oil recirculation & dramatic styling are all features of the FSa range & put this & the other derivatives that cut above the opposition. Specification: Weight: 600g (672g w/silencer) Displacement: 18.0cc Bore: 30.4mm Stroke: 24.8mm Power Output: 1.8PS @ 10, 000RPMPractical RPM: 2, 000
- 11, 000


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O.S. FSa-110 w/F-5040 Silencer (L-OS35410) Designed specifically to offer more power & torque compared to a. 91 size four stroke, yet still fit in the same mounting

Dimensions, the FSa-110 is a real compact powerhouse. Like all FSa series engines, the FSa-110 has near perfect carburation across the RPM range, & thanks to the carefully designed exhaust, a soft yet authoritive note to minimise your presence to the neighbours. Precision carburation, internal oil recirculation & dramatic styling are all features of the FSa range & put this & the other derivatives that cut above the opposition. Specification: Weight: 600g (672g w/silencer) Displacement: 18.0cc Bore: 30.4mm Stroke: 24.8mm Power Output: 1.8PS @ 10, 000RPMPractical RPM: 2, 000
- 11, 000


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O.S. FSa-56 w/F-4040 Silencer (L-OS34300) The new FSa-56 from O.S. is the first engine in a completely new series of advanced four-strokes. The FS ‘ Alpha’ series draws on the experience gained from the Surpass range to develop & refine standards to a new level. The increased capacity compared to the FS-52 Surpass means more power/torque & the new carburettor provides even better throttle control across the entire RPM range! There are innovative features like incorporating the crankcase breather/oil recirculation system into the crankcase to dispense with external nipples & drain tubes as well as a dramatic & futuristic style. An effective & versatile silencer is supplied as standard. Specification Weight:419g/14.8oz w/o silencer Capacity:9.32cc / 0.569 cu.in. Propeller Range:13x 6-7 12x 6-8 13x 6 Silencer:F-4040 Bore:24.0mm / 0.945in Stroke:20.6mm / 0.811in Power Output:1.0PS @ 10, 000 RPM ...

O.S. FSa-81 w/F-5030 Silencer (L-OS34810) The new FSa-81 is a direct replacement for the FS-70 Surpass II, offering greater power & throttle precision in a compact & lightweight design. The crankcase mounting

Dimensions allow the FSa-81 to slot into the same mount that an FS -70S II would for an instant power upgrade. Like the FSa-56, the crankcase breather system has now been incorporated inside the engine to negate the need for an external vent & the excess oil that eminates from it. A propeller locknut assembly is of course standard. The new F-5030 silencer is very effective, thanks to its internal baffle & carefully matched internal volumes & opassages. The design allows a huge range of outlet positions to accomodate almost every model. Even the distance away from the engine can now be adjusted. The latest 60RA carburettor now features a constant velocity inlet for enhanced throttle response & reduced spitting. Specification: Weight: 556g 19.63oz Propeller Range: 13x 7-9, 14x 6-7 Silencer: F-5030 Displacement: 13.26cc 0.809 cu.in. Bore: 27.7mm 1.091in. Stroke: 22.0mm 0.866in. Power Output: 1.3PS @ 11, 000 Practical RPM: 2, 200
- 12, 000


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O.S. MAX 10LA Silv. w/871 Silencer (L-OS11411) Although the smallest engine in the O.S. range, the Max 10LA packs quite a punch, whilst producing an amazingly low exhaust note. The highly baffled exhaust system is effective yet does not heavily restrict the performance. Small engines also need to be light, & the Max 10LA has complementary features like a plastic carburettor to help in this direction. Specification: Propeller Range: 7x 4 7x 5 ...