Lycoming O-145

The O-145 was produced in three major versions, the O-145-A rated at 55 hp (41 kW), the -B rated at 65 hp (48 kW), and -C rated at 75 hp (56 kW). The "B" model was the major production model, with the "A" and "C" produced in much smaller quantities.[1][2]

All models of the series had the same bore, stroke, and displacement, additional horsepower being generated by increasing compression ratio and maximum rpm. All use a Stromberg NA-S2 or NA-S2A or Marvel MA-2 or MA-2-A carburetor. The dual ignition versions use two Scintilla SF-4L, SN4LN-20 or -21, Superior SMA-4 or Edison-Splitdorf RMA-4 magnetos.[1][2]

The original O-145-A produced 55 hp (41 kW) at 2300 rpm, weighed 165.5 lb (75 kg), and featured single ignition. In an attempt to compete with the Continental A-65, Lycoming boosted the rpm and power output to 65 hp (48 kW) at 2550 rpm, and finally 75 hp (56 kW) at 3100 rpm. The O-145 had a hard time competing with the same horsepower Continentals due to its smaller displacement, which resulted in a steeper torque curve.[1][3]

The GO-145 is a geared model, introduced in 1938, that uses a 27:17 reduction ratio (1.59:1) gearbox to produce 75 hp (56 kW) at 3200 crankshaft rpm, giving 2013 propeller rpm. The engine employs a gearbox bolted to the front of the engine and the resulting engine weighs 193 lb (88 kg) without starter or generator. The GO-145 suffered from a poor reputation for reliability, because pilots mis-handled the engine, running it at too low a cruising rpm and causing gearbox wear as a result.[1][2][3][4]

The series' type certificate expired on 2 November 1950 and no O-145-B1 or -C1 or GO-145-C1s engines produced after 1 August 1941 and O-145-B2, -B3 or -C2, or GO-145-C2 or -C3s produced after 24 August 1949 are eligible for certification. The single ignition O-145-A series, O-145-B1, and -C1 are not covered by the original type certificate.[1]

Lycoming ended production of the O-145 and replaced it with the O-235 series.[3]

O-145-A

Four-cylinder, direct drive, 55 hp (41 kW), single ignition[2]

O-145-A3

Four-cylinder, direct drive, 55 hp (41 kW), single ignition, with starter and generator installed[3]

O-145-B on display at the Air Zoo

O-145-B1

Four-cylinder, direct drive, 65 hp (48 kW) at 2550 rpm, single ignition, 155 lb[1]

O-145-B2

Four-cylinder, direct drive, 65 hp (48 kW) at 2550 rpm, dual ignition, 166 lb[1]

O-145-B3

Four-cylinder, direct drive, 65 hp (48 kW) at 2550 rpm, dual ignition, 169 lb[1]

O-145-C1

Four-cylinder, direct drive, 75 hp (56 kW) at 3100 rpm, single ignition, 155 lb[1]

O-145-C2

Four-cylinder, direct drive, 75 hp (56 kW) at 3100 rpm, dual ignition, 166 lb[1]

GO-145-C1

Four-cylinder, reduction gearbox, 75 hp (56 kW) at 3200 rpm, single ignition, 182 lb[1]

GO-145-C2

Four-cylinder, reduction gearbox, 75 hp (56 kW) at 3200 rpm, dual ignition, 193 lb[1]

GO-145-C3

Four-cylinder, reduction gearbox, 75 hp (56 kW) at 3200 rpm, dual ignition, 195 lb[1]

O-145

• Aeronca Chief 50L, 50LA, 65LA
• Aeronca Super Chief 65LB
• Aeronca Tandem 50TL, 60TL, 65TL
• Airdrome Fokker D-VIII
• Luscombe 8B
• Mooney Mite M-18L
• Piper J-3L Cub, most often the 65 hp version
• Piper J-4F Cub Coupe
• Piper PA-8 Skycycle
• Carlson Skycycle
• Piper PA-15 Vagabond
• Porterfield Collegiate LP-50, LP-55, LP-65
• Taylorcraft BL series (BL-50, BL-65, BL-12-65, etc.)
• Taylorcraft DL
• Taylorcraft Plus C

GO-145

• Piper J-5B Cub Cruiser[3]
• Funk B75L[3]
• General Skyfarer[3]
• Rich Twin 1-X-2[3]
• Shirlen Big Cootie
• Stinson 10B Voyager

Data from Type Certificate 210[1]

Comparable engines

• Continental O-170
• Franklin O-150

Related lists

• List of aircraft engines