109 Belly Guns?

[Tony Williams]

A couple of comments:

The 30mm MK 108 could not be synchronised for the same reason that the MG-FF and all other Oerlikon-type API blowback guns could not be; the mechanism wasn't suitable. All of these guns fired from an open bolt, so when the synchronising gear tripped the mechanism, the bolt had to trundle forward, collect a new round from the belt or magazine, chamber it, and then fire it. All this took far too long for the precise timing needed to ensure that the shells wouldn't hit a propeller blade.

The Bf 109 installation of a single MG 151/20 in a belly pod was not followed up because it had to be synchronised, which meant that the electrically-primed version of the 151 had to be used. The hub gun used the percussion-primed variant. Since the ammo was incompatible but easily confused, it was felt that the risk of loading the wrong ammo was too great.

Tony Williams: Military gun and ammunition website and discussion forum

[Krusty]

Tony, any info on the 30mm gondolas? I believe the R5 rutsatz, according to the webpage link listed?

[butch2k]

The Rustsatz V was never attributed to anything on the Gustav G-1 to G-6 and the Rustzustand R5 was a modification made to recce a/c (G-8).

Rustsatz V according to K-4 documents (could apply to G-10 and G-14) is described as "luftfilter für ansaugleitung"

MK108 gondolas were never given any designation nor any official part number.

[HoHun]

Hi Tony,

>Since the ammo was incompatible but easily confused, it was felt that the risk of loading the wrong ammo was too great.

Hm, I'm not sure that makes sense. The propeller hub cannon could easily be converted to electrically primed ammunition, too. (Wasn't it you who taught me that on the Fw 190, the outer MG151/20 were electrically primed for this very reason? :-)

Regards,

Henning (HoHun)

[Tony Williams]

Yes it could, Henning, but I suspect that practical considerations decided the issue. AFAIK the only plane to see service with the MG 151E was the Fw 190. All other planes used the percussion version. This meant that production rates for the percussion version of the gun and ammunition would have been much higher. If it had been decided to switch the Bf 109 entirely to the electric-primed gun, the production rates for the two types would have had to be changed. Then you would have the transitional problem, with older Bf 109s still having the percussion gun while newer ones had the electric - I doubt that it would have been feasible to make enough E guns and ammo to do a retrospective switch.

Basically, especailly at this relatively late stage of the war, I suspect that it would all have been too much trouble.

Tony Williams: Military gun and ammunition website and discussion forum