Continental O 300

Development

The C-145 was developed from the 125 hp (93 kW) C-125 engine. Both powerplants share the same crankcase, although the C-145 produces an additional 20 hp (15 kW) through a longer piston stroke, higher compression ratio of 7.0:1 and different carburetor jetting.

The O-300 is a modernized C-145 and retains the same weight, dimensions, bore, stroke, compression ratio, displacement and output power of the earlier engine.

GO-300

The GO-300 employs a reduction gearbox, so that the engine turns at 3200 rpm to produce a propeller rpm of 2400. The GO-300 produces 175 hp (130 kW) whereas the ungeared O-300 produces 145 hp (108 kW).

The GO-300 engine has a TBO (Time Between Overhaul) of only 1200 hours, while 1800 hours is the standard for ungeared O-300 engines. The GO-300 engine also suffered reliability problems as a result of pilots mishandling the engine and operating it at too low an engine rpm. This caused the Cessna Skylark to develop a poor reputation for engine reliability. Many Skylarks flying today have been converted to different larger displacement direct drive engines.

Variants

C145

Six-cylinder, 145 hp (108 kW), direct-drive engine.

C145-2

O-300

Modernized C145, 145 hp (108 kW), direct drive engine.

O-300-A

O-300-B

O-300-C

O-300-D

O-300-E

Limited production for the Beagle B.218X twin that never went into production

GO-300

Geared O-300, 175 hp (130 kW) at 3200 crankshaft rpm, 2400 propeller rpm.

GO-300-A

GO-300-C

GO-300-D

Voyager 300

Liquid-cooled, fuel-injected version developing 170 hp (127 kW) at 2,700 rpm.

Rolls-Royce-Continental O-300

Licence production in the United Kingdom.

O-300

Aeronca Sedan

Baumann Brigadier

Cessna 160 - intended for production model

Cessna 170

Cessna 172 and T-41 Mescalero

Maule M-4

Meyers MAC-145

Taylorcraft 15

Temco TE-1A

Globe Swift

GO-300

Cessna 175

Goodyear GZ-19 and GZ-19A

Voyager 300

Alexeev Strizh

Specifications (O-300)

Reference: Engines for Homebuilt Aircraft & Ultralights

General characteristics

Type: 6-cylinder air-cooled horizontally opposed aircraft piston engine

Bore: 4  ¹⁄₁₆ in (4.0625 in resp. 103.12 mm)

Stroke: 3  ⁷⁄₈ in (3.875 in resp. 98.425 mm)

Displacement: 301.4 in³ (4.94 L)

Length: 39.75 in (101.0 cm)

Width: 31.5 in (80.0 cm)

Height: 23.25 in (59.0 cm)

Dry weight: 268 lbs (121.5 kg) dry, without starter or generator

Components

Cooling system: Air-cooled

Performance

Power output: 145 hp (108 kW) at 2,700 rpm

Specific power: 0.58 hp/in³ (26.5 kW/l)

Compression ratio: 7.0:1

Power-to-weight ratio: 0.54 hp/lb (0.89 kW/kg)