The Sergant Type A is a four-cylinder in-line, separate, air-cooled engine developed in the 1920s.
The housing is made of aluminum, the shaft of mangano-siliceous steel. The valves are in the bottom of the cylinders with rocker arms above.
The lubrication is done under pressure by a gear pump, in the bottom of the crankcase which contains the oil for 5 hours of flight. Distribution by camshaft. Variable advance Scintilla magneto ignition. Fuel supply loaded and Zénith carburetor.
The propeller is mounted on a hub geared down by spur gears, following the steel flywheel wedged on the shaft. The propeller was in direct gear or three reductions were 14/35, 15/34 and 16/33, which at 3200 turns gives the propeller 1275, 1410 and 1540 turns.
The cooling is provided in an original way: a nozzle open towards the front channels the air in a chimney, the shape and section of which distribute the air current equally to all the cylinders which carry vertical fins.
The Poncelet Vivette and Castar could easily be converted into a moto-cruiser by installing a Sergant engine.
4 cylinders in line
Displacement: 760 cc
Power: 16 HP at 3200 rpm, 17.5 hp at 3500 rpm
Bore 54.5 mm
Stroke 80 mm
Weight: 46 kg with accessories and propeller hub
Length with hub: 0.776 m
Height: 0.565 m
Width: 0.34 m
All Aero 