The LORRAINE STERNA engine is directly derived from the LORRAINE-PETREL engine (in service in French and foreign Aeronautics) whose endurance and safety qualities are now enshrined in several years of use.

Thanks to its robustness, the STERNA engine could be overloaded to the ground by more than 30% of its normal power for take-off, and again this overload is lower than that achieved during the bench tests, which leaves there also a significant margin of safety.

Oilpan. - The housing is in two parts: cast aluminum upper housing, bearing the 7 bearings of the crankshaft, and lower housing, forming an oil bowl.

Crankshaft bearings. - The upper casing assembly and the 7 bearing caps made of duralumin are the bearings of the crankshaft. These bearings have been fitted with smooth steel bushings. The middle bearing and the rear bearing are mounted on a roller bearing..

Cylinders. - The cylinders are made of steel, screwed into the cylinder head.

Cylinder heads. - The cylinder heads are of the Monobloc cast aluminum type.

Crank shaft. - This piece, which is very important in a water-cooled engine, is treated with C.N.R. steel with maximum precision. It is statically and dynamically balanced.

Crank. - The main rod is of the fork type fixed by the central pad and the auxiliary rods pivot on this pad. The connecting rods are section H..

Bearings of connecting rods - The fork rod bearing, made of steel, is internally regulated and electrically treated externally. The auxiliary rod is trunnioned by means of a 2-part lead bronze ring.

Pistons. - The pistons are made of forged aluminum with 3 sealing rings and 2 scraper rings.

Distribution. - The cylinder heads support the 4 camshafts and T-shaped pushers that strike the valves two by two. The valves are 4 in number per cylinder.

Water pump. - This pump is centrifugal type turbine.

Oil pump. - The oil pump is of the gear type.

Ignition. - The ignition consists of two magnetos RB, type P 12, and AVIA wire ramps (harness?) and spark plugs.

Supply. - AM fuel pumps, type 14 CM, and two horizontal LORRAINE boosters provide power.

Supercharger. - Centrifugal LORRAINE, single speed or 2 speed, with automatic clutch, with steel turbine.

Intake limiter. - LORRAINE with automatic opening.

Gearbox. - The reduction of the propeller is done by means of a LORRAINE reduction gear, of the epicycloidal type with spur gears.

Supercharger starter. - The start is carried out by carbonated gasoline starter type Viet.

The engine can accommodate all types of generators from 300 to 1,200 watts. The generators are mounted at the rear of the engine in the V of the cylinders and inwards. The power take-off is on the axis of the crankshaft; flexible shaft drive and disc clutch.