Development of the DB601A Engine mounted gun.

[schwarze-man]

I have found it difficult to get info about the development of the DB601 engine mounted gun, particularly for the Bf109E.
I have found details for the Bf109F and onwards, but the developments with the earlier 109E series and the prototype development seem obscure. I wonder if I am just missing a great reference on this subject?
My own attempts at research in the Bf109E Ersatzteil-liste do not show any reference to Engine mounted weapons, other than the top mounted guns.
The DB601A has the blast tube and mounting point for a hub firing gun, but no references to any gun or gun fittings for one. The closest thing I have found is the open spinner with blast reinforcement, that was fitted to some 109E aircraft. The 109E fuselage possibly has a cut-away at the front where the gun and its mount would probably need to fit but, the engine oil tank seems to occupy that space. Also, it would seem that the machine-gun ammunition boxes may also be an issue, certainly if the engine gun had a drum type ammunition feed.
I would be grateful for any info, or advice about this.
Cheers

SM

[sidney]

There was no DB 601 A engine mounted gun for Bf 109 E model, which entered the mass/serial production (i.e., Bf 109 E-1, E-3, E-4, E-7 and E-8). There was provision for its installation there alright, but that was about it.

[Graham Boak]

I did read that the original intention was to have an engine-mounted cannon on the Bf.109C, but that never happened either. Seeing the comment on space for the drum, I wonder if the intention was not to use the drum-fed MG.FF but rather the MG.151, which also was running late. As a side-effect, the He.100 was designed for three MG.151s, so wold have had a very weak armament (2x7.9mm mgs) had it ever actually reached production for 1940.

[schwarze-man]

Thank You Sidney. Do you know if there were any prototype installations? The requirement for the engine to have the attachment point for the gun mounting and the blast tube through to the propeller seems to have been an important design factor from the early DB600, through the 601A/N and finally fitted with a gun, the MG151, on the DB601E.
It is interesting that many modern sources cite the fitment of these weapons, going into the detail of "problems with vibration and heat"? Beyond that I can find no details.

Thanks again,

SM

[schwarze-man]

Thanks Graham.
Yes, no doubt in my thoughts that there was a desire to fit an engine mounted gun. It does seem strange to me that Messerschmitt seems to have effectively precluded the installation of such a weapon when he designed the 109E but Daimler-Benz built the engine to fit it.
I assume that prototype installations on engines actually occurred before the DB601E with the MG151 was produced?

Cheers

SM

[Graham Boak]

I think you can guarantee that trials installations were done long in advance of adoption.

I understand that the spinner intake was actually used for cooling purposes, so perhaps DB were well aware of the problems and didn't expect the gun to be fitted into the DB.601A, but left the option open for later developments?

[sidney]

You are welcome SM.

According to Thomas Hitchcock "One-O-Nine Gallery", page 24. Only very limited numbers of the E-2 variant were built, for which the V20 prototype served as basis. It was armed with two wing-mounted, and one engine-mounted Motorkanone MG FF cannon, which gave considerable trouble in service, as well as two synchronized MG 17s cowl machine guns. In August 1940, II./JG 27 was operating this type.

However, there is no reference to confirm it in Prien, Stemmer and others, JFV 4/I, article on II./JG 27, Battle of Britain.

Regards,
Sinisa

[schwarze-man]

Yes, I also do expect that trials were done Graham. The spinner opening certainly does offer a route for airflow to the rear of the engine, with the gun fitted it functions as a source of airflow to help cooling and purging a working gun. However, the alternative engine part instead of a gun mounting on the rear of the engine is a plain blank. That is not to say the opening could not have been used for air, just that I see no evidence on any parts of the 109E aircraft that took "cooling" air from the gun tube, other than the alternative spinner with a hole in. So that is a mystery, what was the "cooling" airflow used for when, as always, no gun was fitted. Another question is why sealed spinners were used when the cooling air was needed on some aircraft?
Certainly, DB built the engine with the option, same as the later 601E/F etc, where the no gun engines (eg Bf110) got the same gun tunnel and blast tube as engines fitted with guns, but were fitted with a blank plate over the rear mounting point and sealed spinners.
Cheers

SM

[schwarze-man]

Thanks Sidney.
Would be great to see original data on the E-2 if it did trial engine mounted weapons.

Cheers

SM

[halus901]

I'd rather see a German document source, but found this excerpt from a Chicago based magazine publication from 1941:


https://books.google.ca/books?id=EBt...ooling&f=false

It simply states cooling air from the cannon hub opening was used to control the temperature of electric generators at the rear of the engine. Prior to that, the wording infers the hollow hub was designed to mount a cannon in the engine.



So question still remains, was the cooling from this entry point necessary, or just a coincidental design? As mentioned, later E-4 and E-7 Emils had the spinner capped. No more hole so that seems to say the cooling air from that entry point wasn't necessary??





regards,
Jack