Henri Vaslin built a horizontally-opposed four-cylinder engine that was installed on the Dewoitine D7 in 1923.

“Vaslin on Dewoitine”

-Producing 16 hp, this Vaslin engine was also installed on the Avia BH-16. Two engines were installed on the DeMonge 7.4 aircraft.

“Vaslin engine top view”

-Since the cylinders were completely opposite each other, it is assumed that one connecting rod was normal and the opposite one was forked.

-Data are known for two Vaslin engines, both four-cylinder and with dual ignition. The first, producing 15 hp at 1,600 rpm, produced up to 20 hp at takeoff at 2,400 rpm.

The other one, from 1923, produced 24 hp at 2,500 rpm and increased to 28 hp at 3,000 rpm (takeoff power).

Below we show a better photograph of this brand's Type A, with 18 hp at 2,000 rpm. It has four horizontal cylinders in pairs, two inter-connected on each side.

“Vaslin A engine”