Luftwaffe Fuel Names

[Kurfürst]

You can read some of the more interesting German aviation fuel related material on my site, collected from various sources. A lot more can be found at the Fischer-Tropsch Archive site, but most of it is so technical that it may be uninteresting for most of us.

http://www.kurfurst.org/#engines, see aviation fuel section.

In short, B-4 and C-3 are designations for German synthetic fuel. B-4 is roughly 87 octane, whereas C-3 is roughly 96 octane. Take note that the Germans measured octane number by a different method than the Allies, and that to composition and performance of especially C-3 changed during the course of the war. Briefly, early was C-3 was equivalent to 96/130 Grade Allied fuel, and from late-1942, 96/145 Grade fuel.

There's little rule as for what fuel was used, it depended on the engine, and these were not seperate 'bomber' and 'fighter' fuels. B-4 was typically used by 109s (with exceptions: DB 601N powered E-something/N and F-1, F-2 versions used C-3) and bombers from early to mid war; late war 109G/K with methanol boost was typically prescribed to use C-3, but could 'fall back' to use B-4 if that was available, with little or no performance loss. BMW 801D engined Fw 190s used C-3 (very early 190s with 801C theoretically used B-4 but I believe they used the better C-3 regardless).

Almost all bombers used B-4 for their engines, but this was not set in concrete either: there's evidence that 1940 Ju 88As and late 1944 He 111H-16s used C-3, even though there would be no advantage from it; probably it was handier at the airfield than B-4, and so was used..