2 Stroke Engines

Like its larger brothers the 25LA replaced its FP predecessor and offers the kind of reliable performance you would expect from O.S. with all the design advantages of the latest LA series. The 'safety' rear needle valve assembly, extended crankshaft and that unique shape is guaranteed to impress even the most conservative of tastes.
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Developed from the fabulous 25FX, the new 25AX inherites the dramatic styling of its AX siblings and provides class leading power and torque for both sports flying or even Pylon racing!

The new E-3080 muffler is extremely effective and has been optimised to prevent any unneccesary power loss.

The mounting pattern ensures that the new 25AX will just drop in to any model designed around the old 25FX.

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Designed specifically for light weight and high power output from a compact crankcase, the Max 35AX is an ideal engine for 'Fun Fly' and 3D flying.

The new crankcase follows the theme of all the new AX range and the 35AX will fit exactly where the old 32SX did without modification.
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Following on from the concept developed in the 70SZ-H, the latest 37SZ-H brings a new level of performance to '30-class' helicopters.

Just about everything has been changed compared to the 32SX-H in the pursuit of power and control. That super-rigid crankcase contains a highly developed, ringed piston/liner set and optimised crankshaft for the right combination of power and smoothness. The new carburettor has been purpose designed for precision control and is capable of being operated by push-pull linkages if required.

This is the perfect engine to compliment your new Hirobo Sceadu Evo and move your flying on to a new level.
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The 39 was born out of the need to get the maximum power from the smallest possible crankcase. It is in fact very similar in size to a 25. Trying to fit the 39 in a mount designed for a 40 would be somewhat tricky. Keeping the capacity as a 30 class engine is more inline with its intended purpose.

This engine is particularly suited to the rigours of 3D Fun Fly competition flying, where the limitations of model size and engine capacity are controlling factors. It is no coincidence that most of the competitors in Fun Fly at the Nationals choose the Irvine 39 as their powerplant. These pilots demand power, torque and throttle response and the 39 delivers this in style.

From the precision cast crankcase, through the true ABC piston liner to the CNC machined, Jetsream carburettor, the Irvine 39 shouts quality.
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The new Irvine 40 ABC Mk4

Physically identical to the popular 40LA but with a 20% increase in power and no discernible increase in weight. Like all engines in the LA range the 46LA comes with an A3 glowplug as standard plus the highly effective E-3030 Silencer.

Details

The new Irvine 46 ABC Mk4

• C.C. - 7.50
• Bore - 22.25
• Stroke - 19.28
• Power (kW) - 1.18/16,500
• R.P.M. - 2000-12800
• Weight - 443g
• Rec Prop - 11 x 7
• Crankshaft Thread - 1/4 UNF

Related products:

1. APC 11" x 7" Propeller

2. MASTER 11" x 7" G3 Propeller

The first engine in the AX series, the 46AX features a new rear-mounted needle valve system that tolerates crash damage better. The new carburettor has been refined further to make adjustments more precise and throttling even more progressive. The amazing new 'P-Box' silencer is both distinctive in styling as well as being functional. Inside, the 'ringless' piston/liner system delivers strong power and improved life.

Details

The original Irvine 53 was a hard act to follow, but needless to say, the new Irvine 53 ABC MkII is more than up to the task.

The new engine shares the same crankcase dimensions as its predecessors and the new 40 and 46 MkIV stablemates, so you can be sure that fitment is not an issue.

The adoption of the latest ringless piston and liner technology, with a totally new bore to stroke ratio, moves the performance on to a new level. The latest C40H carburettor unleashes that performance with the kind of control that you would expect from an engine that has become one of the best sellers in the UK. Smooth, precise and on tap when you need it.

Details

Designed to combine maximum power with razor sharp throttle response in the smallest possible crankcase, the 55AX has the same mounting dimensions as the popular 46AX above, but an increase in power to 1.70PS. The dramatic AX fin styling is used for optimum cooling and the rearward angled needle on the the type 40J carb makes adjustments safer. Perfect for sport, scale and aerobatic models.
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The best '50-class' engine on the market just became amazing with the introduction of the new 50SX-H Hyper.

That CNC machined cylinder head has been developed to give better power and improved cooling at the same time. The new carburettor has also been improved to help extract more power than the standard engine without sacrificing the throttle precision you have come to expect from OS helicopter engines.

This truly is the 'best' engine in the 50-class and is fast becoming the best seller as well. It's an OS, what else would you expect!!
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The max 50SX-H Hyper has established an enviable reputation for power, reliability and ease of use. The Max 55HZ Hyper moves that to a whole new level!

Designed primarily with the demands of the 3D pilot in mind, the 55HZ Hyper delivers 61 size performance in a 46 size crankcase. That power comes from the extensive experience that OS has gained over many years and working extensively with the worlds top pilots to refine all aspects of the engine without compromise in any area.
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A special Limited Edition version of the fabulous Max 55HZ Hyper in stunning black external finish and matching black tuned silencer. For the man that likes his model products a little more 'exclusive'!!

Both the engine and the silencer are engraved to show the 'Limited Edition' nature of the pair and all of this comes at a price that is actually less than buying the standard engine and muffler together!!!

There will only ever be one batch in the UK so buy yours now while stocks last.

Designed as a replacement for the long established Max 61FX, the new Max 65AX has all the features of the new AX series, such the same mounting bolt pattern and silencer bolt dimensions, making a direct replacement for most 61 class engines. The real bonus is more power and torque for the same basic external dimensions.

Like all the AX series, cooling has been improved by the use of deep finning on the crankcase and cylinder head combined with the new fin pack shape.
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Developed directly from the feedback received from top FAI and 3D pilots throughout the world, the MAX 70SZ-H Ring produces copious quantities of power across the rev range without sacrificing its ability to perform precision hovering. There's a stronger crankcase (with 6-point mounts), 3-needle carburettor and a revised liner/port design to give you the performance you need to beat the world! Particularly suited to the demands of 3D flight.

The third engine in the new AX range of high performance 2 stroke engines fills a convenient gap between the existing 61FX and 91FX, yet features the radical new style pioneered with the fabulous 55AX. The new 75AX is supplied complete with the latest P-Box design silencer for improved noise suppression. By keeping the lower crankcase dimensions the same as the 61FX, you can be sure that it will fit in all models designed for a .61, making a power upgrade very simple. The 75AX features the latest O.S. ringless piston technology with multi-layer cylinder coating and high precision Type 61A carburettor with angled safety needle valve assembly.
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Designed to replace the 91FX yet retain the same mounting dimensions but with increased power and torque.

The design has been optimsed to produce strong torque and power at modest RPMs and exploit the extremely effective nature of the E-4040 silencer. This concept becomes important as noise becomes less and less acceptable.

Like all the latest AX series engines, the highly effective and unique cooling fins keep temperatures under control and the carburettor, the precision you would expect from OS.
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The distinctive shape is hard to ignore, and with peak power of 3.1PS at 9000RPM, you can be sure that this engine loves big propellers! OS recognised that engines of this size are often used in scale models and have developed a silencer system that allows adaption to some of the 'tightest' installations. The carburettor features a neat needle valve that protects fingers while adjusting, yet is simple & accessible.

Propeller Range: 15x10-12 16x8-10

The largest engine in the FX series boasts impressive bhp for its compact external dimensions. Its 'porting' has been optimised for low RPM's and is quite happy turning big props on a scale model or low diameter/high-pitch props on a pattern aircraft. The 'ringed' piston on this size of engine allows easy starting and has a forgiving nature when it comes to 'tuning' the main needle for optimum performance.
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The largest single cylinder engine in the O.S. range, the BGX-1 was designed to offer smoother running and a more compact size than equivalent capacity petrol engines together with light weight and easy operation.

The BGX-1 achieves all of these goals and produces 4.1BHP at 10,000rpm.

Ideal for large aerobatic, sport and scale applications and designed for 18 x 8 to 20 x 8~10 propellers. Comes complete with an E5010 silencer and cast radial mount.
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Since the introduction of the original OS rotary engine in 1970, the design has stood the test of time and in this latest version, has been brought fully up to date. Just about every aspect has been upgraded in the new Type II version, both internally and externally. It is the area of carburation that has seen the most dramatic change, in the form of a specifically designed, twin-needle version complete with a velocity-stack. All the upgrades are intended to improve the ease of use and the durability of the engine. Many take advantage of the latest metallurgy to do so.
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