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Lycoming R-680

 

Lycom-R-680

 

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.
 
Lyc-R680-02
 
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)

 

 

 

 

 


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