Air-cooled, reciprocating piston, internal combustion engine with cylinder heads forming arcuate or S-shaped cooling ducts therebetween

In a air-cooled, reciprocating piston, internal combustion engine which defines a longitudinal axis and which includes at least one row of cylinders comprising individual cylinder heads arranged side-by-side, said cylinder heads being provided with cooling ribs extending substantially normal to the axes of the cylinders, said cylinder heads including means for accommodating attachment bolts, said cylinder heads each having at least one inlet valve and one exhaust valve, the valve stems of which extend substantially parallel to the axes of the cylinders and are situated such that the plane passing through said valve stems lies at an acute angle to said longitudinal axis of the internal combustion engine, said cylinder heads each including an intake duct located on a side thereof which is swept by cooling air, said intake duct having its inlet opening aligned approximately centrally of the cylinder head, said cylinder heads each including an exhaust duct extending substantially perpendicularly to the exhaust air side, and a lateral deflector being provided adjacent the end cylinder head in each row, the improvement wherein each of the cylinder heads includes a central area between the valve stems therein, and wherein each cylinder head is externally shaped to provide at least one arcuate or S-shaped cooling air duct between it and an adjacent, similarly constructed cylinder head, and wherein each cylinder head includes an enclosed cover plate section facing the associated cylinder of the cylinder head, said enclosed cover plate being provided with cooling ribs at the cylinder head periphery, substantially on the exhaust air side thereof, and the side thereof facing the inlet valve stem, and includes boss means for accommodating attachment bolts.