O.S. MAX 120 AX RC Airplane Engine

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Perfect for 3D, precision and sport flying!

Admit it: if you could ratchet up horsepower without having to increase the mounting space, you’d probably jump at the chance. Well, here it is. The 120AX boasts 25% more displacement than a .91 (think of the bigger props you can swing!) — and bolts into the same space, with almost no extra weight. And that’s not all. The 120AX’s innovative Power Box muffler offers mounting versatility that translates into value. Plus, the angled heat sink head not only looks sharp, it adds more surface area, for better cooling. Here’s a golden opportunity to boost your airplane's flying capabilities — with almost no modification!

With the 120AX, there’s no need to buy an expensive aftermarket muffler!

The included Power Box comes with two adapters — one of which turns the muffler 90° to become a “Pitts style“.

With the 120AX and .91 side by side, you can see how they’re virtually identical in size — but you’ll enjoy a big difference in performance!

Notes from our tech department:

This is the O.S. Max Two-Stroke 1.20AX Ringed Engine with Muffler. FEATURES Model Application: Ideal for 3D, Precision and Sport flying Mounting Application: Mounts in same space as the .91FX (actual mounting dimensions vary slightly, see SPECS) Internal Construction: Steel piston ring and liner, aluminum piston Muffler: E-5020 Power Box with extension and 90 adapters Carburetor: 70D with rearward angled needle valve for safety Glowplug: O.S. 8 supplied with engine, A5 (OSMG2693) will also work Warranty: Two-year limited INCLUDES O.S. Max Two-Stroke 1.20AX Ringed Engine with E-5020 Power Box Muffler, 8 glow plug, muffler adapter, prop washer and lock nut, needle valve extension cable,instruction manual and decal sheet, two muffler screws, two muffler extension bolts, two long muffler bolts. REQUIREMENTS Fuel: Two-Stroke with 18 lubricant and 5-20 nitromethane Propeller: 15x10-12 or 16x8-10 Field Equipment: Glow starter, fuel filter, fuel pump, fuel tubing SPECIFICATIONS Displacement: 1.218 cu in (19.96cc) Bore: 1.197 (30.4mm) Stroke: 1.083 (27.5mm) Practical RPM: 1,800 - 9,500 RPM Power Output: 3.1 PS, 3.06HP9000 RPM Weight of engine: 29.0oz (823g) with muffler Weight of muffler: 7.074oz (219.2g) with 90 adapter installed Weight of muffler: 7.907oz (245g) with extension installed Crankshaft thread size: 516-24 Distance Between Mounting Holes Same Side: 0.98 (25mm) Distance Between Mounting Holes Opposite Side: 2.3 (58mm) Distance Center of Crankcase to End of Crankshaft: 4.3 (109.5mm) Distance Center of Crankcase to Drive Hub: 2.7 (69.8mm) Width Between Mounting Tabs: 2.6 (67mm) Width of Crankcase Below Mounting Tabs: 1.8 (46.5) Length from Backplate to End of Crankshaft: 5.5 (139.9mm) Length from Backplate to Drive Hub: 3.9 (100.2mm) HeightBottom of Crankcase to Top of Cylinder Head: 4.3 (109.2mm) HeightBottom of Mounting TabsTop of Cylinder Head: 3.4 (85.7mm) Distance center to center of muffler mounting holes: 48mm (1.89) Needle Settings: High Speed: 2 - 2.5 turns out from fully closed Low Speed: 34 turn out from fully closed with the throttle fully closed