Question about octane fuel requirements for DB601A and DB601N engines for the Bf109E

[Larry Hickey]

Hello,

My understanding is that a Bf109E-4 (or any other E subtype) with an 87 in the octane fuel triangle below the fuselage fuel fill point indicated that the a/c had a standard DB601A engine. Whereas for the plane to be equipped with an upgraded DB601N engine it would have been indicated by a "100" for the octane rating in the fuel triangle. I know that the DB601N became standard for the "F" subtype, but I know that some 109Es also carried this more powerful engine and were thus designated as Bf109E-4/N subtypes.Do I understand this correctly?

Regards,

Larry Hickey
EoE Project Coordinator

[Clint Mitchell]

Larry,

My understanding is:

DB601A = 87 octane fuel = 87 in triangle

DB601N = 100 octane fuel = C3 in triangle

[Larry Hickey]

Clint,

There are examples of Bf109E octane triangles with the number "100" in them, as well as others with "C3." Are these designations then interchangeable?

Regards,

Larry Hickey
EoE Project Coordinator

[Clint Mitchell]

I presume that some used the octane number and some used the type of fuel. Interesting to know if any show B4 for the DB601A. For example:

DB601A = B4 - 87 octane fuel = 87 in triangle or B4 in triangle?

DB601N = C3 - 100 octane fuel = 100 in triangle or C3 in triangle

[cjme201262]

C2 = 100 natural
C3= 100 synthetic

[Larry Hickey]

Clint,

I don't ever recall seeing "B4" inside a Bf109 fuel octane triangle.

Regards,

Larry Hickey
EoE Project Coordinator

[Clint Mitchell]

Thanks,

[John Beaman]

Larry:

The 601 was the standard engine for the E model. It used 87 octane fuel. the 601N was used in some Es and required 100 octane fuel.

Pending development of the 601E, the 601N was also used in the F-2, hence the 100 in the octane marking. The F-4 used the 601E which used 87 octane. The only F-4 you will see with a 100 octane marking is the F-4Z which used a nitrous oxide boost system under pressure, for limited times. There was no F-2Z

It is my understanding that B4 was the artificial version of 87 fuel and C3 was the artificial version of 100 fuel. These were not interchangeable in the aircraft fuel system, hence the triangle warnings. I have never seen a C2 in any photo. Later versions of the 605D could be "tuned" in the field to use either type of octane rating, but this was in the G-10 and K-4 machines.

[Larry Hickey]

John,

Thanks. So for an aircraft to have the designation Bf109E-4/N (or E-3/N) it would have had to have had a 601N engine, and the dead give away from photos would be a "100" in the fuselage octane triangle. Is that correct? I'm concerned only with the period to the end of 1940.

Regards,

Larry Hickey
EoE Project Coordinator

[Primoz]

Originally Posted by Larry Hickey

John,
... and the dead give away from photos would be a "100" in the fuselage octane triangle. Is that correct?

More likely "C3" or "c3" or "C-3":

http://www.messerschmitt-bf109.de/di...otonummer=1087

http://www.messerschmitt-bf109.de/di...otonummer=3250