The Caudron G.4 was powered by two eighty-horsepower Le Rhône rotary engines,²⁰ which were lubricated by a constant flow of light-weight castor oil, most of which was burned off by the heat of the cylinders that it lubricated. As the Crown Prince no doubt became fascinated by the sight of an entire engine that rotated, he may have been tempted to tug at the propeller to watch it turn the engine – and been less concerned about the resulting flow of liquid from the oil reservoir that accompanied each motion.

At about this time Hübener was pleasantly surprised to learn that one of his FFA 25 comrades was also a hometown friend from Bremen, twenty-year-old Leutnant Caspar Kulenkampff-Post (generally referred to as Kulenkampff). Hübener’s biography noted:

‘The fact that Hübener and Kulenkampff were new to combat flying necessitated a “switching around” in the make-up of the crews. Leutnant Göring was given the tall, blond and good-natured Kulenkampff for an observer, while Graf von Schaesberg … was assigned to “tap the helmet” of the new pilot, Unteroffizier Hübener.’²¹

Kulenkampff was a bright young man for whom the outbreak of war meant not being able to accept a Rhodes scholarship to Oxford in September 1914.²² An avid and skilled horseman, he accepted a commission into Uhlan Regiment Nr. 15. When trench warfare obviated the need for mounted troops to cross the battle lines swiftly, Kulenkampff applied for aviation training and, in November 1915, he was assigned to the Flieger-Beobachterschule [aviation observer school] at Künigsberg²³ on the barren Baltic coast in East Prussia. Upon completion of the course of study, he was assigned to FFA 25.