Updated: 22-Mar-2018
The horizontally-opposed 4-cylinder engine in the photograph is a 60 hp Dumon that is used in Drone aircraft. We guess its 2-stroke cycle, and the four high-voltage coils on the engine are very similar to those of Citroën's 2CV engine.
"Dumont boxer"
Engines of DUMON
Model: 4 cyl., boxer, 60 CV
Arquitecture: 2-stroke4-cylinder Horizontally opposed
Cooling:
Total Displacement:
Bore / Stroke:
Power: 60 HP
Weight:

"Dumon boxer"