The Lycoming R-680 is a nine-cylinder air-cooled radial engine, the first aero engine produced by Lycoming.

Pressure lubrication is to the crankshaft, master rod, link pins, cam drive gears, and main accessories drive shaft and gears.

First run in 1929, the engine was produced in two types the E and B series both are essentially the same, the B4E was available in a trainer version with a front exhaust collector for use without cylinder air baffles.

Equipment was a tachometer drive at ½ canshaft speed, exhaust ring, cowling and air cleaner.

Accessories available were a generator and starter,

Variants:
R-680-B4E
Rated at 225 hp at 2100 rpm.

R-680-E3A
Rated at 285 hp at 2200 rpm.

R-680-13
Rated at 300 hp at 2200 rpm.

Applications:
Beech AT-10 Wichita
Boeing-Stearman PT-13
Cessna AT-8/AT-17
Curtiss-Wright AT-9
Fleetwings BQ-2
Spartan NP-1
Stinson Airliner
Stinson Reliant
Stinson Vigilant
Waco S Series (very rare facory authorization)

Specifications:

Type: 9 cylinder air cooled radial
Rating: 210 hp at 2000 rpm
Displacement: 680 cu.in
Compression ratio: 5.2-1
Bore: 4 5/8 in
Stroke: 4 1/2 in
Length: 43 1/8 in
Diameter: 43 1/4 in
Weight: 465 lb dry
Fuel consumption: not more than .55 lb/hp/hr
Oil consumption: not more than .035 lb/hp/hr
Lubrication: 1 pressure pump, 2 scavenger pumps (in one unit)
Ignition: Scintilla dual magneto type SC-A
Carburation: 1 Stromberg NA-R7
Spark plugs: 2 per cylinder

R-680-E3A
Type: Nine cylinder air-cooled radial
Bore: 4 5⁄8 in (117 mm)
Stroke: 4 1⁄2 in (114 mm)
Displacement: 680 cu.in (11.15 litres)
Length: 37.5 in (953.1 mm)
Diameter: 43.5 in (1104 mm)
Dry weight: 515.46 lb (233.9 kg)
Valvetrain: One inlet and one exhaust valve per cylinder at 30 degrees.
Fuel system: single-barrel carburetor
Fuel type: 87 octane rating gasoline
Oil system: Full pressure type
Cooling system: Air-cooled
Power output: 330 hp (246 kW) at 2,300 rpm at sea level
Compression ratio: 7:1
Power-to-weight ratio: 0.64 hp/lb (1.05 kW/kg)

In 1932, the engineers at Lycoming Engines became aware that the United States Army Air Corps (USAAC) wanted a high performance engine that could produce at least one horsepower per cubic inch (46 kW/L) of engine displacement and that a contract had been made with Continental Motors, Inc., Lycoming’s main rival in the general aviation engine market. Lycoming’s management wanted to be considered for development of the next generation engine, but no USAAC development contract was signed. Still determined to become known as a high performance engine manufacturer, Lycoming began an experimental, high-performance engine of its own. After spending US $500,000, and after many attempts to develop a successful engine, it finally came close to the USAAC specifications with the 1,200 hp (895 kW) O-1230 engine.

Lycoming’s O-1230 engine design was a 12-cylinder liquid-cooled horizontally-opposed low-profile piston engine that could be mounted either horizontally, buried in the wing of a multi-engine aircraft; or vertically, in the fuselage of a single engine fighter. From 1935 the engine design proceeded at a faster pace after a number of former Continental engineers, who had become unhappy with the working conditions there, joined Lycoming.

The same year the USAAC became interested in the O-1230, and began supporting the engine development program. In 1936, the single-cylinder development tests exceeded expectations, passing its 50 hour test requirement. The full-size engine was ready for testing in 1937, and was rated at 1,000 hp.

The last Vultee A-19 that had been ordered by the USAAC was delivered as the XA-19A, fitted with an O-1230-1 offering 1200 hp. It first flew on May 22, 1940. This aircraft was subsequently re-engined with a Pratt & Whitney R-1830-51 and redesignated.

Continued development of the O-1230 reached its peak when the engine was rated at over 1200 hp. It was as powerful as the Allison V-1710, but with a narrower cowling than the Allison V12 engine. The O-1230 was not well received by aircraft manufacturers, because it was not very reliable at that power setting.

Specifications:
O-1230-1
Type: 12-cylinder, Geared, liquid-cooled, horizontally-opposed piston engine
Bore: 5.25 in (133.4 mm)
Stroke: 4.75 in (120.7 mm)
Displacement: 1233.9 cu.in (20.219 L)
Dry weight: 1342 lb
Valvetrain: Overhead camshaft
Cooling system: Liquid
Reduction gear: 0.40
separate cylinders
hemispheric cylinder head design
one-piece cylinder head for each bank
Power output: 1000 hp@3100 rpm, 1200 hp@3400 rpm, 1,275 hp (951 kW)
Specific power: 1.03 hp/cu.in
Power-to-weight ratio: .95 hp/lb

The Lycoming O-145 is a family of small, low-horsepower, four-cylinder, air-cooled horizontally opposed aircraft engine produced from 1938 until the late 1940s by Lycoming Engines. The family includes the reduction-geared GO-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.

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.

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.

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.

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.

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

Variants:
O-145-A
Four-cylinder, direct drive, 55 hp (41 kW), single ignition

0-145-A3
Four-cylinder, direct drive, 55 hp (41 kW), single ignition, with starter and generator installed

O-145-B1
Four-cylinder, direct drive, 65 hp (48 kW), single ignition

O-145-B2
Four-cylinder, direct drive, 65 hp (48 kW), dual ignition

O-145-B3
Four-cylinder, direct drive, 65 hp (48 kW), dual ignition

O-145-C1
Four-cylinder, direct drive, 75 hp (56 kW), single ignition

O-145-C2
Four-cylinder, direct drive, 75 hp (56 kW), dual ignition

GO-145-C1
Four-cylinder, reduction gearbox, 75 hp (56 kW), single ignition

GO-145-C2
Four-cylinder, reduction gearbox, 75 hp (56 kW), dual ignition

GO-145-C3
Four-cylinder, reduction gearbox, 75 hp (56 kW), dual ignition

Applications:
O-145
Airdrome Fokker D-VIII
Piper J-3L Cub, most often the 65 hp version
Carlson Skycycle
Piper PA-8 Skycycle

GO-145
Piper J-5 Cruiser
Funk B75L
General Skyfarer
Rich Twin 1-X-2
Shirlen Big Cootie

Specifications:
GO-145-C2
Type: Four-cylinder, reduction-geared engine
Bore: 3.625 in (92 mm)
Stroke: 3.500 in (89 mm)
Displacement: 144.5 cu.in (2.4 L)
Dry weight: 193 lb (87.5 kg)
Fuel system: Stromberg NA-S2 or NA-S2A or Marvel MA-2 or MA-2-A carburetor
Fuel type: minimum 73 octane
Cooling system: air-cooled
Power output: 75 hp at 3200 rpm (56 kW)
Specific power: 0.52 hp/cu.in (23.3 kW/L)
Compression ratio: 6.5:1
Power-to-weight ratio: 0.39 hp/lb (0.64 kW/kg)

In 1932, the engineers at Lycoming Engines became aware that the United States Army Air Corps (USAAC) wanted a high performance engine that could produce at least one horsepower per cubic inch (46 kW/L) of engine displacement. Determined to become known as a high performance engine manufacturer, Lycoming began an experimental, high-performance engine of its own. After spending US $500,000, and after many attempts to develop a successful engine, it finally came close to the USAAC specifications with the O-1230 engine, which was a 12-cylinder liquid-cooled horizontally-opposed low-profile piston engine. In 1936, the single-cylinder development tests exceeded expectations, passing its 50 hour test requirement. The full-size engine was ready for testing in 1937, and was rated at 1,000 hp. Continued development of the O-1230 reached its peak when the engine was rated at over 1,200 hp (895 kW). The O-1230 was not well received by aircraft manufacturers, because it was not very reliable at that power setting.

It was apparent that the O-1230 engine was uncompetitive with the high performance air-cooled engines that were then becoming available. The US Navy began funding the development of the Lycoming engine. The funding enabled Lycoming’s engineers to attempt rescuing the design by proposing a 24-cylinder H-configuration engine made by stacking two of the O-1230 engines, gearing them together to one common output shaft. The new engine was the H-2470. It weighed in at 2,430 pounds and produced 2,300 hp (1,700 kW) at 3,300 rpm.

The Navy specified the H-2470 for the Curtiss XF14C-1 experimental fighter. After some rigorous testing the engine’s poor performance led to the substitution, before the aircraft flew, of a Wright R-3350 radial engine, which was also having technical problems but was considered to be more reliable than the H-2470. The testing program was eventually terminated due to the poor performance of the aircraft.

The USAAC was also interested in the H-2470, and installed and flew it in the Vultee XP-54 prototype fighter. The XP-54 was the only aircraft to actually use it for flight, but like the Navy’s XF-14C, the XP-54 never went into production.

Applications:
Curtiss XF14C
Vultee XP-54

Specifications:
Type: 24 cylinder, ‘H’ piston engine
Bore: 5.25 in. (133.35mm)
Stroke: 4.75 in. (120.65mm)
Displacement: 2467.8 cuin (40.44 Li)
Dry weight: 2,430 lb
Cooling system: Liquid-cooled
Power output: 2,300 hp at 3,300 rpm