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The Lorraine 9N Algol was a French 9-cylinder radial aeroengine built and used in the 1930s. It was rated at up to 370 kW (500 hp), but more usually in the 220–300 kW (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 (370 kW) at 3,000 m (9,800 ft)

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

Specifications

Data from Jane's All the World's Aircraft 1938

General characteristics

• 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)

Components

• 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

Performance

• Power output: rated 221 kW (296 hp)
• Compression ratio: 6:1

References

1. ^ Grey, C.G. (1972). Jane's All the World's Aircraft 1938. London: David & Charles. pp. 48d–49d. ISBN 0-7153-5734-4.
2. "To Paris". Flight. No. 8 December 1938. p. 534.
3. Société Nationale de Constructions de Moteurs: Argentuil (in French). Argentuil: SNCM. November 1938. Archived from the original on 16 October 2014. Retrieved 11 October 2014.
4. Parmentier, Bruno. "Sema 12". Aviafrance. Retrieved 14 October 2012.

• 1930s aircraft piston engines
• Aircraft air-cooled radial piston engines
• Lorraine aircraft engines