Lorraine Algol


The Lorraine 9N Algol was a French 9-cylinder radial aeroengine built and used in the 1930s. It was rated at up to, but more usually in the range.

Design and development

The Algol was 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.

Variants

;9A:
;9Ab:
;9Ac:
;9Ad:
;9N Algol:
;9Na Algol:
;9N Algol-Junior
;9N Algol-Major
;9N Algol-Amelioré
;Type 120 500 hp: A developed version with supercharger and reduction gear giving at

Applications