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==