Lorraine Algol Explained

The Lorraine 9N Algol was a French 9-cylinder radial aeroengine built and used in the 1930s. It was rated at up to 500abbr=onNaNabbr=on, but more usually in the 300- 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 carburetterbut 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 500hp at 3000m (10,000feet)[1]
  • Applications

    Notes and References

    1. Book: Société Nationale de Constructions de Moteurs: Argentuil. November 1938. SNCM. Argentuil. 11 October 2014. fr. dead. https://web.archive.org/web/20141016180638/http://dev.museesafran.com/wp-content/uploads/2012/10/1350047099-livres-espace-patrimoine-saf2012_0048826. 16 October 2014.