OS .91 SX-H C-Spec

Taking heli performance to a new level.

It's the largest engine displacement allowed in FAI F3C and AMA-sanctioned heli competitions!

• Newest version of the .91 SX-H features advancements that can make the difference between winning and losing!

• Foremost among its upgrades is a three-needle carb, for the ultimate in fine-tuning.

• A lighter piston and conrod, combined with a more balanced crankshaft, significantly reduce high-rpm vibration.

• The round gold "Hyper" head with horizontal fins offers better cooling and sharper looks.

• Still retains the .91 SX-H's push/pull throttle arm, dual ball bearings and ringed construction.

Here are the advantages of the C Spec over the old 91SX-H

• Lower vibration at high r.p.m. which comes from refinement of crankshaft balancer shape and lighter weight of piston, connecting rod and piston pin.

• More powerful which comes from refinement of combustion chamber and crankshaft intake port shape which is tapered - i.e. wider at crankcase side than at carb side.

• Gold 'Hyper Head' as standard for better cooling.

• Three needle carb (NEW 60K) is included instead of two needles - easier adjustment for the low mid and high ends. Also the Carb has graduation marks to make set up easier and also includes the push/pull throttle arm.

• Black Alumite crankcase

• Same mounting hole spacing as the 61SX-H making the 91 SX-H C-Spec interchangeable.

The carburetor on the .91 SX-H Ringed Special Heli Engine features three needles: one for high-end, one for low-end, and a third for all-important mid-range hovering.

OS .91 SX-H SPECIFICATIONS

• Displacement: 0.912 cu. in. (14.95 cc)

• Output: 3.0 hp @ 15,000 rpm

• Bore: 1.091 in (27.7 mm)

• Practical rpm Range: 2,000-16,000

• Stroke: 0.976 in (24.8 mm)

• Weight: 19.29 oz (547 g)

• Includes: #8 glow plug, needle adjusting screws, woodruff key

	Download OS 91 SX-H C-Special Manual		OS 91 SX-H C-Spec - Taking heli performance to a new level. It's the largest engine displacement allowed in FAI F3C and AMA-sanctioned heli competitions!

OS Glow Plugs for 2 & 4 Stroke Engines

	[OS71641300] OS P3 Ultra Hot Turbo Plug [OS71641600] OS P6 Hot Turbo Plug [OS71641700] OS P7 Medium Turbo Plug [OSPLUG8] OS Glow Plug 8 for 2 stroke engines [OSPLUGA3] OS Glow Plug A3 for 2 stroke engines [OSPLUGA5] OS Glow Plug A5 for 2 stroke engines [OSPLUGF] OS Glow Plug F for 4 stroke engines

OS Helicopter Engines

	Download OS 37 SZ-H Manual		OS Engines 37 SZ-H helicopter - Designed to deliver premium performance for 30-sized machines, from extreme aerobatics to stable hovering!

	Download OS 50 SX-H Manual		OS 50 SX-H - Developed expressly for F3C M-class competition machines utilizing .50-size engines, the .50 SX-H Ring heli features the same mounting hole spacing as the .46 FX-H Ring engine so upgrading's a breeze.

	Download OS 91 SX-H C-Special Manual		OS 91 SX-H C-Spec - Taking heli performance to a new level. It's the largest engine displacement allowed in FAI F3C and AMA-sanctioned heli competitions!