O.S. 105HZ 1.05 Helicopter Engine

Tower Stock# LXBUUB  •  Manufacturer Stock# 18700
O.S. 105HZ 1.05 Helicopter Engine (large view)
Notes from our tech department:
This is the 105HZ 1.05 cu in Helicopter Engine from O.S. Engines.


Same mounting dimensions as a .90 cu in engine
Machined blue anodized aluminum heatsink cylinder head
Velocity stack increases airflow and enhances engine performance
Backplate accepts the Futaba BPS-1 RPM sensor for the GY701 and
CGY750 gyros
Ideal bore and stroke ratio for lowest vibration
Two year limited warranty through Hobby Services beginning at date of


105HZ 1.05 cu in Helicopter Engine with 61E Carburetor
#8 Glow Plug
Air Funnel
0.1mm Head Gasket
0.2mm Head Gasket (installed)
Instruction Manual


Fuel: Heli blend with 15% nitro content
Glow starter and field equipment


Displacement: 1.048 cu in (17.17 cc)
Bore: 1.142" (29mm)
Stroke: 1.024" (26mm)
RPM Range: 2,000 - 16.500
Output: 3.7 ps @ 15,000 RPM
Weight: 21.03oz (596g)
Crankshaft Size: UNF 5/16-24
Carburetor Settings;
High Speed Needle Valve: Approx. 2 turns open from fully closed
Medium Speed Needle valve: 1 turn open from fully closed
Idle Mixture Control Screw: At basic position when engine left
Distance/Center of Mounting Holes Same Side: 0.98" (25mm)
Distance/Center of Mounting Holes Opposite Side: 2.04" (52mm)
Crankcase Width Below Mounting Tabs: 1.7" (43mm)
Crankcase Width at Mounting Tabs: 2.4" (61mm)
Width from Throttle Arm to Center: 1.6" (42mm)
Height from Bottom of Mounting Tabs to Cylinder Head: 3.1" (79mm)
Height/Bottom Mounting Tabs to Muffler Mounting Holes: 1.7" (42.8mm)
Height/Bottom of Crankcase to top of Cylinder Head: 3.9" (99mm)
Length from Backplate to Front Bearing: 3.2" (82.6mm)
Length from End of Crankshaft to Center of Engine: 3.5" (88.7mm)

jxs 01/30/12

See Tower Catalog page 174.
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