The OS MAX 55AX (40K) is designed for pilots who want the highest power output in a compact, lightweight package. Sharing the same mounting dimensions as the popular 46AX, the 55AX delivers a significant performance boost with 1.75PS (1.68hp) of usable power, making it an exceptional upgrade for .46-size airframes without modification.

Featuring the distinctive AX-series cooling fin design, the 55AX maintains excellent temperature stability under load, while the rearward-angled needle valve ensures safer and easier carburettor adjustments. The new 40K carburettor enhances fuel metering and contributes to increased horsepower over the older 40J-equipped engines.

Delivered with the E-3070 Silencer, the 55AX offers strong thrust, crisp throttle response, and reduced noise levels—making it ideal for a wide range of sport, scale, and aerobatic aircraft.

Key Features

• Same mounting dimensions as the 46AX – simple drop-in upgrade

• Increased power output: 1.75PS / 1.68hp @ 16,000rpm

• Improved 40K carburettor for more horsepower and better response

• AX-series cooling fin design for efficient heat management

• Safety-focused rearward-angled needle valve

• Supplied with the E-3070 Silencer for quieter, efficient running

• Perfect for sport, aerobatic, and scale aircraft in the .46–.55 class

Perfect For

• Sport aircraft

• 3D and aerobatic models

• Scale aircraft

• Pilots upgrading from the OS 46AX or other .46-class engines

• Models needing more thrust without increasing engine size

Product Summary

The OS MAX 55AX (40K) brings more power, better cooling, and improved throttle response to the proven AX platform. With its drop-in compatibility and enhanced 40K carburettor, it’s an ideal choice for anyone looking to extract maximum performance from a .46-size airframe.

Specifications

• Weight: 525g (18.52 oz) with silencer

• Capacity: 8.93cc (0.545 cu.in.)

• Propeller Range: 12×7–8, 13×6–7

• Bore: 23mm (0.906")

• Stroke: 21.5mm (0.846")

• Power Output: 1.68hp (1.75 PS) @ 16,000 rpm

• Practical RPM Range: 2,000 – 17,000

Why Buy From Probuild Aircraft

• ✅ Official UK OS Engine Stockist

• ✅ 100% Genuine Products

• ✅ Trusted by Top International Pilots

• ✅ Fast, Reliable UK Shipping

• ✅ Trusted by Pilots Since 1993