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Basse und Selve Bus.IV
1917 - 1918



Since 1906, Basse und Selve AG was a famous factory with a leading position in the production of aluminium pistons and, similarly to many other industries, was involved in the war production during World War I, on behalf of Idflieg (Inspektion der Fliegertruppen, Air Force Inspectorate). At the end of 1915, B&S overcame even the scepticism of the military authorities on the technology of aluminium pistons and obtained an order from Idflieg for an inline 6-cylinder engine for 300 hp. A first 20-liter version for 260 HP was consequently developed with 4 valves per cylinder driven by an overhead gear-driven camshaft. It was originally equipped with pistons made of aluminium. The validation and approval tests of 1916/17 were interrupted several times due to many problems and B&S was forced to a complete re-design of the engine. As a result of the changes and of the new displacement of 22.7 liters, the engine Bus.IV passed the approval tests in October 1917 with 278 HP in normal operating conditions. B&S produced 330 examples of this engine to equip the heavier military aircraft of classes G and R: bombers and long-range reconnaissance. Subsequently, in order to reach higher performance, especially at high altitude, two other engines of the type "surcompressed" were developed from Bus.IV and were denominated Bus.IVa and Bus.Vü: these ones had an increased compression ratio (from 4.7 to 5.6 and finally 6.3), an increased bore (from 155 mm to 160 mm and finally 165 mm) and delivered a rating power of 300 hp and 350 hp respectively at 1400 rpm and 1800 m altitude. The engines Bus.IV and Bus.IVa were the greatest inline 6-cylinder engine built in series during the First World War.

Technical specifications

ManufacturerBasse und Selve, Altena (Westfalia), Germany, from 1917 to 1918
DescriptionBasse und Selve, Altena (Westfalia), Germany 1917-1918
Stroke200 mm
Bore155 mm
Displacement22650 cm³
Compression ratio4.7
Power303 CV at 1450 rpm (maximum sea level power); 278 CV at 1400 rpm (sea level rating power)
Specific fuel consumption230 g/hp/h
Specific power13.4 hp/litre
Valvetrain systemfour overhead valves per cylinder controlled by an overhead gear-driven camshaft
Fuel feeding systemwith two single-barrel gasoline carburetors, equipped with altitude compensation system
Ignition systemtwo spark plugs per cylinder fed by two high voltage magneto distributors Bosch Zh6, firing order: 1-5-3-6-2-4
Cooling systemliquid-fed by a centrifugal pump
Lubrication system410 forced by means of a 2-cylinder reciprocating pump
Weight410 kg
Mass-to-power ratio1.71 kg/hp


Rumpler C.IV (reconnaissance aircraft)

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Hansa-Brandenburg W.29 (fighter and reconnaissance aircraft seaplane)

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 - Museo Motori UNIPA

 - Museo Motori UNIPA

 - Museo Motori UNIPA

 - Museo Motori UNIPA
Testi e immagini di Giuseppe Genchi
Sito realizzato da Pasquale Pillitteri