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Lorraine 9N Algol


The Lorraine 9N Algol was a French 9-cylinder radial aeroengine built and used in the 1930s. It was rated at 500 hp (375 kW).

A conventionally laid out radial engine, with nine cylinders in a single row. The crankcase was a barrel-shaped aluminium alloy casting, with an internal integral diaphragm which held the front crankshaft bearing. Forward of the diaphragm there was an integrally cast cam-gear case for the double track cam-ring. The reduction gear was housed under a domed casing attached to the front of the crankcase.

Flange-mounted steel barrels were bolted to the crankcase and enclosed with cast aluminium alloy, screwed-on, cylinder head with integral cooling fins. The pistons were also made of aluminium alloy and had floating gudgeon pins. The nine pistons drove the single throw crankshaft via one channel-section master rod and eight circular section auxiliary rods. The master rod had an integral, split type big-end. The crankshaft was machined from a single forging, with bolt-on balance weights.

The Algol had a single pair of overhead inlet and exhaust valves per cylinder. The cam-ring drove roller tappets, mounted in the cam-case, which in turn operated rocker arms, fitted with ball bearings, via pushrods. The cam-ring was concentric with the crankshaft and driven via epicyclic gears.

Most Algols were conventionally aspirated via a single carburetter but at least one 1938 variant used a form of fuel injection, where fuel was blown into the induction system rather than the cylinder head.


ANF Les Mureaux 120
Bernard 161
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Bloch 500
FBA 290
Potez 33
Romano R.16
Weymann 66


Type: 9-cylinder single row supercharged radial
Bore: 140 mm (5.51 in)
Stroke: 150 mm (5.90 in)
Displacement: 20.78 L (1,268 cu in)
Length: 1.347 m (53.2 in)
Diameter: 1.275 m (50.2 in)
Dry weight: complete 390 kg (860 lb)
Valvetrain: one inlet and one exhaust overhead valve per cylinder, operated with rocker arms, pushrod driven via roller tappets bearing on a double track cam-ring
Fuel system: single Stromberg carburettor, heated by exhaust
Fuel type: petrol
Cooling system: air-cooled
Reduction gear: 11:17
Power output: rated 221 kW (296 hp)
Compression ratio: 6:1



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