O.S. MAX 91HZ-PS Ring (L-OS18620) Designed primarily for the 3D flight & dramatic aerobatic manouevres. Compared to the old Hyper the new 91HZ-PS offers enhanced hovering stability as well as power at high speed to meet the further sophisticated 3D competition manouevres. A new design piston & crankshaft reduces vibration to provide further, stable torque over the entire RPM range. The rectangular heatsink head is completely included in the cooling shroud for better cooling. The black alumite finish with O.S. & 91HZ-PS logo impart a distinctive image. A Thermo insulator is installed on the carburetor mounting spigot & helps shut out engine heat to the carburettor, which in turn ensures a stable fuel/air mixture. The 91HZ-PS is equipped with a new, bigger capacity PD-08 pump & matched 61B-P carburettor plus integral regulator, which assures a consistent fuel supply irrespective of violent changes in model attitude. Combined with O.S. pump system, internal parts improvements same as the 91HZ contribute to stable power output & smoother higher engine performance. Specification: Weight: 635g Displacement: 14.95cc Bore: 27.7mm Stroke: 24.8mm Power Output: 3.5PS @ 15000RPMPractical RPM: 2000
- 16000
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This version of the Max 91HZ series utilises a completely different system for supplying & regulating the the fuel supply to the carburettor & is called DRS (Demand regulator system). Unlike the Max 91HZ-PS, the Max 91HZ-R utilises a pressure bleed from the crankcase to pressurise the main fuel tank. The pressurised fuel feed is then regulated by a newly designed regulator that is well isolated from the heat of the engine through its mounting position. That regulated fuel supply is then feed into the new 61E carburettor. The serious 3D flier now has the choice between a mechanically pressurised fuel system (Max 91HZ-PS) or the tank pressurised system in the Max 91HZ-R. It is purely a matter of personal choice for the pilot. What other manufacturer gives you that level of choice in one engine size? Mechanically, the Max 91HZ-R is identical to the other engines in the Max 91HZ range. Specification Weight: 625g (22.05 oz.) Displacement: 14.95cc (0.912 cu.in.) Bore: 27.7mm (1.091") Stroke: 24.8mm (0.976") Power Output: 3.4 hp @ 15, 000 rpm Practical RPM: 2, 000
- 16, 000 Manufacturer: Ripmax Model: O.S. MAX 91HZ-R Ring (L-OS18640)
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O.S. MAX 95AX w/4040 Silencer (L-OS19120) Designed to replace the 91FX yet retain the same mounting

Dimensions but

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O.S. OMA-3820-1200 Brushless Motor Legendary O.S. quality in a brushless electric motor! This one is intended as a replacement of. 25 class 2 stroke engines using 3 or 4 cell Li-Po packs & will provide strong, linear power. This new range of brushless motors features a unique. O.S. designed cooling system, a strengthened centre body & large ball bearings. The propeller driver has been machined from stainless steel for both strength & durability. Each motor is balanced during manufacture for optimum running & reliability. Supplied with a rear mount & 3.5mm gold connectors as standard accessories.

Specification Weight: 155g Turns: 10 Resistance: 21.4 m Ohms Bearings: 3 Current Range: 30
- 40A ESC Timing Degrees: 20
- 30 Degrees KV RPM: 1200 Max Current: 75A for 10 secs Pole: 14 Power Output: 440W Nominal Voltage: 11.1
- 14.8v (3
- 4S Li-Po) No Load Current: 1.9A Max Efficiency: 85% Shaft dia: 5mm Shaft Length: 11.5mm





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O.S. OMA-3820-1200 Brushless Motor (M-OS51011000) Legendary O.S. quality in a brushless electric motor! The OMA-3820-1200 provides strong, linear power & is intended as a replacement for. 25 two-stroke engines using 3S & 4S Li-Pos. Features include a unique. O.S.
- designed cooling system, a strengthened centre body, large ball bearings & a stainless steel propeller driver for maximum strength & durability. The motor is balanced during manufacture to ensure optimum running & reliability. Supplied with a rear mount & 3.5mm gold connectors as standard accessories. Specification: Diameter: 37.5mm Length: 47.3mm Shaft dia: 5mm Shaft length: 11.5mm Lead wire length: 90mm Male connector: 3.5mm diameter Weight: 155g Poles: 14 Resistance: 21.4m Ohm Current range: 30
- 40A k V: 1200 Li-Po: 3S, 4S Bearings: 3 ESC timing: 20-30 degrees (high) Turns: 10 Max current: 75A / 10 seconds Power output: 440W Nominal voltage: 11.1
- 14.8V No-load current: 1.9A Max. efficiency: 85%


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O.S. OMA-5020-490 Brushless Motor (M-OS51013000) Legendary O.S. quality in a brushless electric motor! The OMA-5020-490 provides strong, linear power & is intended as a replacement for. 40
-. 50 two-stroke &. 70 four-stroke engines using 5S & 6S Li-Pos. Features include a unique. O.S.
- designed cooling system, a strengthened centre body, large ball bearings & a stainless steel propeller driver for maximum strength & durability. The motor is balanced during manufacture to ensure optimum running & reliability. Supplied with a rear mount & 4mm gold connectors as standard accessories. Specification: Diameter: 50mm Length: 57.5mm Shaft dia: 6mm Shaft length: 11.5mm Lead wire length: 110mm Male connector: 4mm diameter Weight: 350g Poles: 14 Resistance: 23m Ohm Current range: 50
- 60A k V: 490 Li-Po: 5S, 6S Bearings: 3 ESC timing: 20-30 degrees (high) Turns: 16 Max current: 90A / 10 seconds Power output: 1110W Nominal voltage: 18.5
- 22.2V No-load current: 1.5A Max. efficiency: 85%



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O.S. OMA-5025-375 Brushless Motor (M-OS5101400) Legendary O.S. quality in a brushless electric motor! The OMA-5025-375 provides strong, linear power & is intended as a replacement for. 55
-. 61 two-stroke &. 91 four-stroke engines using 6S to 8S Li-Pos. Features include a unique. O.S.
- designed cooling system, a strengthened centre body, large ball bearings & a stainless steel propeller driver for maximum strength & durability. The motor is balanced during manufacture to ensure optimum running & reliability. Supplied with a rear mount & 4mm gold connectors as standard accessories. Specification: Diameter: 50mm Length: 62.5mm Shaft dia: 6mm Shaft length: 11.5mm Lead wire length: 110mm Male connector: 4mm diameter Weight: 405g Poles: 14 Resistance: 27.5m Ohm Current range: 50
- 60A k V: 375 Li-Po: 6S
- 8S Bearings: 3 ESC timing: 20-30 degrees (high) Turns: 16 Max current: 90A/ 10 seconds Power output: 1550W Nominal voltage: 25.9
- 29.6V (7S
- 8S Li-Po) No-load current: 2A Max. efficiency: 85%





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O.S. OMA-5025-375 Brushless Motor Legendary O.S. quality in a brushless electric motor! This one is intended as a replacement of. 55
-. 61 class 2 stroke &. 91 class 4 stroke engines, using 6 to 8 cell Li-Po packs & will provide strong, linear power. This new range of brushless motors features a unique. O.S. designed cooling system, a strengthened centre body & large ball bearings. The propeller driver has been machined from stainless steel for both strength & durability. Each motor is balanced during manufacture for optimum running & reliability. Supplied with a rear mount & 4mm gold connectors as standard accessories.

Specification Weight: 405g Turns: 16 Resistance: 27.5 m Ohms Bearings: 3 Current Range: 50
- 60A ESC Timing Degrees: 20
- 30 Degrees KV RPM: 375 Max Current: 90A for 10 secs Pole: 14 Poles Power Output: 1550W Nominal Voltage: 25.9
- 29.6v (7
- 8S Li-Po) No Load Current: 2.0A Max Efficiency: 85% Shaft dia: 6mm Shaft Length: 11.5mm






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O.S. Speed 21VZ-B V-Spec II Engine (L-OS13911) If you want to win World 1/8th Rallycross Championships you need the best engine... & this is it! From tough new aluminium cylinder head with cooling efficiency holes, to the ceramic rear bearing & the specially plated crankshaft with heavy metal balance inserts, the Speed 21 is all about no compromise. The engine of choice for the 2008 World Champion, Atsushi Hara, & most of the top seven finishers! Specification: Length: 65mm
Height: 110.6 Weight: 349g (12.32oz)
Width: 45mm Displacement: 3.46cc (0.211cu.in.) Bore: 16.60mm (0.654in.) Stroke: 16.00mm (0.630in.) Power Output: 2.5PS@34000 rpm Practical RPM: 3000~40000 rpm

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O.S. Speed 21XZ-B Engine (L-OS12186) Developing on the 1/8th Off Road World championship winning engine of 2008, OS has now devoped the latest generation engine called the Speed 21XZ-B. Racing engines are a constant refinement of design & technology rather than a huge leap. The Speed 21XZ-B is case in point. No one area has been dramatically changed but nearly every area has been subtly enhanced. Whether that is the DLC coated, tungsten weighted & silicon filled crankshaft, the Ceramic rear bearing or the shape of the cylineder ports, everything has been developed to make the Speed 21XZ-B a step forward in performance. OS racing engines have always been some of the easiest to set up & use & this is no accident. Years of racing experience with top drivers such as Mark Pavidis & Atsushi Hara has established how an engine should respond at the highest levels & remain consistent. There are small detail changes such as the lower, lighter heatsink head for a lower centre of gravity & an enhanced 21J2 (B) carburettor for better response & setting. The Speed 21XZ-B has an overall fuel consumption that is 8% better (OS pipe) than its predecessor. That could make the difference when making a decision about the best time to pit! Why not follow the champoins choice & drive the very latest Speed 21XZ-B yourself! Optional items: Super Air Cleaner 203T-2060SC WN Tuned Pipe system (EFRA 2042 homologated)P4 & P5 Turbo plugs (Cooler) Crankshaft locking tool Heavier Flywheels for Mugen & Kyosho Flywheel Puller Flywheel Key Long Plug Wrench Specification: Weight: 355g (12.52oz) Displacement: 3.49cc (0.213cu.in) Bore: 16.27mm (0.64in) Stroke: 16.8mm (0.66in) Power Output: 2.6PS @ 34000rpm Practical RPM: 4, 000
- 40, 000
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