OS MAX AX two-stroke engines are the latest range of high-performance power units designed primarily for sports and aerobatic models. The thoroughly engineered design features a unique ABL (Advanced Bimetallic Liner) insert with a two-layer surface coating of specially developed alloys to minimise friction and wear during operation, ensuring high performance and long life. The futuristically shaped hexagonal cylinder head with large cooling fins provides excellent cooling and allows higher power output with the same overall dimensions as the classic FX range. Thanks to this, you can benefit from the wide range of kits and model plans developed over the last decades for two-stroke OS MAX engines, or achieve a performance increase for your existing model with FX engine!

OS MAX 120 AX RING is a powerful two-stroke engine with a crankshaft and piston ring mounted with a pair of ball bearings, suitable for sport and competition aerobatic models of all types. It is fitted with a 70D twin needle carburettor, the main needle of which is angled backwards for safe adjustment when the engine is running. The basic set also includes a very efficient expansion muffler type E-5020 (Power Box). The direction of the exhaust opening can be changed by turning the rear of the muffler 90 degrees.

The same dimensions as the classic OS MAX 91FX but with 20% more power.
The crankshaft has a thread for the propeller nut UNF 5/16-24.
Recommended propeller dimensions: Sport and aerobatics: 15x10", 15x12", 16x8, 16x10".
Recommended fuel tank: 450-500 ml; 450 ml tank is enough for 10-12 minutes of aerobatics, provided you do not always fly full throttle.
Recommended fuel: at least 18% castor oil or synthetic oil (or mixture of synthetic oil and castor oil), 5-20% nitromethane.
Recommended candle: OS MAX No. 8 or for higher percentage of nitro No. 10.
Engine set includes: OS MAX 120 AX RING engine with RC carburettor 70D, exhaust muffler type E-5020, main needle extension set, glow plug No. 8, instructions.

Technical data
“ Displacement: 19.96ccm
“ Power approx. (3.1) (hp) at 9,000 rpm
“ Speed range: 1,800 - 9,500 rpm
“ Bore: 30,4mm
“ Stroke: 27,5mm
“ Total weight: 892g
“ Carburettor: 70D
“ Shaft thread 5/16"-24 UNF
“ Weight: 647g
“ Length to hub: approx. 100.2 mm
“ Width: approx. 67 mm
“ Height: approx. 109.2 mm
“ Spac. Locating holes lengthwise 25.0 mm crosswise 58 mm
“ Pilot hole Ø 3,2 mm
“ Recommended propellers: Sport and aerobatics: 15x10" / 15x12" / 16x8 / 16x10"

"O. S. ENGINES", based in Osaka/Japan, is one of the world's most renowned model engine manufacturers and has been in existence since 1936 (!). Consistent further development and state-of-the-art production processes have enabled us to achieve a high level of technical development. This is the reason why "O. S."- Engines - advanced and competitively proven 2-/4-stroke engines
Engines for all areas of model making - so popular with renowned experts, too.
Double ball bearing motor with high performance and durability, suitable for all types of aircraft, especially aerobatics and scale models.