Abstract: A single stage axial blower design provides a series of blowers producing a wide range of delivery flow rates even though they have the same outer dimension, drive speed and guide wheel. This is achieved by a structural combination which includes a stationary guide vane wheel (5) of fixed design and impellers (8) which have varying hub diameters (9, 9a, 9b) but the same outer diameter. Thus, a series of blowers having the same external dimensions and the same stationary guide vane structure can be used with a series of air-cooled internal combustion engines which differ from one another in number of cylinders and related cooling requirements.

Abstract: The helical cooling channel in the cooling gap between the cylinder pipe and the associated cylindrical part of the housing and internal combustion engine is formed by a helical spring which is fixed in the cooling gap under radial tension. The helical spring rests against either the cylindrical part of the housing of the internal combustion engine or the cylinder pipe.

Abstract: An internal combustion engine having a retarder and a heat exchanger which re-cools the retarder oil, with cooling air being supplied to the heat exchanger during the braking operation. The internal combustion engine is provided with an exhaust conduit in which is arranged a blocking device for closing off the exhaust conduit during the braking operation, with the thus retained gas flow being utilized for conveying the cooling-air flow to the retarder oil heat exchanger.