During the exhibition at the Grand Palais in 1909 (Paris Motor Show), they made tests on several airplanes. Similar to the first "Dutheil et Chalmers" types, but they differ in having four cylinders. The cylinder heads have some valve chambers fixed to them, and both are surrounded by fins for cooling.

-The cylinder heads are fastened to the cylinders and the central block with four studs each.

"Bertin 4-cylinder"

-In the valve chamber of each cylinder of which there are two horizontally opposed, but only the exhaust valve is controlled mechanically.

-Each pair of cylinders has one carburetor, it looks as if there are two carburetors, but they are incomplete, for they use a common, unique floater in the middle.

-According to the cylinder diameter being 120 mm or 130 mm, the power is 40 or 50 CV.

-There were also other Bertin engines such as the 4-X and 8-X.

-The crankshaft was composed of multiple parts united by conical joints.

"Bertin 8-X at Le Bourget"

-The distribution was characteristic, for each head had two concentric valves, one inside the other.

-The 8-X was used in the Bertin biplane.

-There is a subject that is a little tangent, the known "Bertin's horns" or "augmentors" used in the Ludion air vehicle, powered by rocket engines. (See SNECMA).

-Do not confuse the "Bertin" of the early days with Jean Bertin's "Bertin et Cie" that began its activities just after WWII and changed its name to "Bertin Technologies" in 1999. The latter was dedicated to the R + D (I + D).

"Water-cooled, horizontally-opposed, two cylinder Bertin engine"

-This Bertin two-cylinder engine is restored in the reserve stock at the MAE.

From appendix 6: We found a photograph of a Bertin plane with a Bertin horizontally-opposed, eight-cylinder engine that gave 150 hp. Possibly it is the 8X, and that shows us that this engine was not just experimental, and that it proved to be reliable.

"Bertin with Bertin"

-In this publication on engines, few aircraft or artifacts are displayed, but sometimes the size of the picture does not let us see the engines clearly.

From appendix 7: Bertin began making a V2 engine for the bicycles that he built. He also made one with two horizontally-opposed cylinders.

From appendix 10: Léonce Bertin made helicopters already by the year 1910.

"Bertin helicopter with 2-cylinder engine"

-The engine that was used was a Bertin 2-cylinder engine giving 55 CV. No results are known. But Bertin continued to make more helicopter models and he even made a horizontally opposed 8-cylinder engine as shown in the following photos.

“Two photos of the installed 8-cylinder engine”

-It is not completely sure but the following illustration of a possible plane, -or possible helicopter because of the top structure- that has a horizontally opposed, eight-cylinder engine, is very similar to the one on the Bertin device showed above, and it might be from the same builder.

-For the moment, the horizontal fins with the spark plugs in the middle of them and the circular cylinder heads do not have another example to compare with. Besides they seem to be from the same time too.

“Possible flying machine made by Bertin”