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 500 hp, but more usually in the 300 - 400 hp 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 500 hp at 3000 m

Applications

 * ANF Les Mureaux 120
 * Bernard 161
 * Bloch 120
 * Bloch MB.500
 * Caudron C.180
 * FBA 290
 * Loire 11
 * Potez 33
 * Potez 40
 * PWS-24
 * Romano R.16
 * SAB-SEMA 12
 * Lorraine-Hanriot LH.70
 * Weymann 66