I've been trying to understand what kind of fuel was used for the aviation diesel engines in the interwar-WWII era, primarily the Ju 205, but if you have information for other aviation diesel engines feel free to contribute. On the internet one can find secondary(?) sources (Junkers Jumo 205 C4 ) claiming it used "Schweröl", which translates to heavy fuel oil (Schweröl – Wikipedia ).
Two-stroke diesel engine - Wikipedia points to two references which also apparently mention the use of "heavy oil" by the Ju 205:
Konrad Reif: Dieselmotor Management – Systeme, Komponenten, Steuerung und Regelung (Diesel Engine Management – Systems, Components, Control and Regulation), 5th edition, Springer, Wiesbaden 2012, ISBN 978-3-8348-1715-0, p. 102
Bill Gunston (1995). Classic World War II Aircraft Cutaways. 2nd edition, Bounty Books, London, 2011. pp.46-47
However, I'm finding it hard to believe that these engines actually used heavy fuel oil. That stuff is thick goop, and ships (or power plants) using it have steam heating lines running through the fuel tanks in order to make the oil liquid enough that it can be pumped, and heated further before entering the high pressure injection pumps. AFAIU typical handling temperature is around 40C, and then further heated to about 130C before injecting. I'm just not seeing how such fuel heating systems could be anywhere reasonable on an aircraft. And on an aircraft, you probably have high speed cold air further cooling the fuel tanks when operating at altitude, meaning that keeping the fuel at 40C would require quite a lot of heat.
I'm not aware of any primary sources on this topic (and I don't speak German so I would be unlikely to make any sense of it even if I had), but it wouldn't surprise me if some mention of "Schweröl" made it into the engine documentation as a some sort of colloquial to distinguish it from the aviation gasoline that most other aviation engines used? Anyone know better?
Two-stroke diesel engine - Wikipedia points to two references which also apparently mention the use of "heavy oil" by the Ju 205:
Konrad Reif: Dieselmotor Management – Systeme, Komponenten, Steuerung und Regelung (Diesel Engine Management – Systems, Components, Control and Regulation), 5th edition, Springer, Wiesbaden 2012, ISBN 978-3-8348-1715-0, p. 102
Bill Gunston (1995). Classic World War II Aircraft Cutaways. 2nd edition, Bounty Books, London, 2011. pp.46-47
However, I'm finding it hard to believe that these engines actually used heavy fuel oil. That stuff is thick goop, and ships (or power plants) using it have steam heating lines running through the fuel tanks in order to make the oil liquid enough that it can be pumped, and heated further before entering the high pressure injection pumps. AFAIU typical handling temperature is around 40C, and then further heated to about 130C before injecting. I'm just not seeing how such fuel heating systems could be anywhere reasonable on an aircraft. And on an aircraft, you probably have high speed cold air further cooling the fuel tanks when operating at altitude, meaning that keeping the fuel at 40C would require quite a lot of heat.
I'm not aware of any primary sources on this topic (and I don't speak German so I would be unlikely to make any sense of it even if I had), but it wouldn't surprise me if some mention of "Schweröl" made it into the engine documentation as a some sort of colloquial to distinguish it from the aviation gasoline that most other aviation engines used? Anyone know better?
