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Tech question regards U4 mod to Bf109 g6 & 14


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Gentlemen,

I have a question regarding the Bf109 G6 or G14 u4.

http://www.network54.com/Forum/257037/mess...od+of+G6+or+G14.

"Gents,

I am in need of a little clarification regarding the U4 modification sometimes seen on G6 and G14 variants.

It is my understanding that aicraft so modified did NOT have an ejector port for the spent rounds or links. Is that correct?

If the above is true, then didn't the spent MK108 rounds pose a fire and explosive problem given that said spent rounds would have transferred more gun gas into the spent shell collection point than it was originally designed to cope with when it was expected to catch MG151/20 shells?

In the drawings on this sight I note that the underside plan for the G10/U4 and K4 both show an ejector port, but it is in my opinion too small to fit an MK108 case, is it rather for the belt links and does that then indicate that the MK108 shells were kept onboard on these airframes as well?

Help please, this is keeping me awake at nights!<grin>"

 

Any takers?

 

Kais.

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I have always thought the shells and disintegrating link were ejected via chutes connected to ejection port of the cannon. This chute then takes the spent casings and link to a port in the fuselage/wing on the ventral surfaces.

 

But its a good question. To be truthful I can't find a definitive answer in any ref material. I can't imagine any value in a figter plane for hanging onto the brass...I've never seen any collection point on any cutaway diagrams, so I'd be going with a 'its meant to be there' port.

 

Mk108 Round

 

The round itself doesn't seem like its size is that much greater than the 151/20...only the head is wider and the casing a little thicker. The Mk103 looks beastly by comparison and its also 30mm...It looks like a .222 swift but on streroids.

 

Wumm/Vincent one of the other 109 Boffins might know for sure though...I'll be interested to know for myself.

 

Cheers Matt

PS welcome to LSP as well Kais :-)

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Matt, Steve,Gents,

Thanks very much for your prompt and considered responses.

Steve, as you say, "this is late war German " so often as not what appears logical is not what happens! :blink:

Nice to finally be part of the LSP exchange.

 

Salute!

 

Kais.

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Guest Vincent

Gentlemen,

I have a question regarding the Bf109 G6 or G14 u4.

http://www.network54.com/Forum/257037/mess...od+of+G6+or+G14.

"Gents,

I am in need of a little clarification regarding the U4 modification sometimes seen on G6 and G14 variants.

It is my understanding that aicraft so modified did NOT have an ejector port for the spent rounds or links. Is that correct?

If the above is true, then didn't the spent MK108 rounds pose a fire and explosive problem given that said spent rounds would have transferred more gun gas into the spent shell collection point than it was originally designed to cope with when it was expected to catch MG151/20 shells?

In the drawings on this sight I note that the underside plan for the G10/U4 and K4 both show an ejector port, but it is in my opinion too small to fit an MK108 case, is it rather for the belt links and does that then indicate that the MK108 shells were kept onboard on these airframes as well?

Help please, this is keeping me awake at nights!<grin>"

 

Any takers?

 

Kais.

 

Hi

 

The U4 specification manual is very clear on this : the planes did not have an ejection slot for the spent shells which remained inside the plane, just like on the MG151/20 version. This is valid for the G6, the G14 and the G10s.

 

Was it dangerous ? No because you have to remember that the spent ammo bin was permanently ventilated and because there was a blast discharge tube exiting behind the last exhaust pipe on the right side.

 

The K4 was the only version to have the combined ejector slot (cases+links). Its dimensions are in accordance with the Rheinmetal recommendations.

 

Then why was the K4 the only version to have it ? Simply because the K4 was the only version of the 109 that had the MK108 installed as standard. For the other versions, it was important to be able to use as many common parts with the regular Gs as possible, incuding the belly panel.

 

Also overlooked by most modelers, the G10/U4 versions used the same compressed air bottles in the tail area as the G2 used for the MG17s. The refill point was behind a hatch on the right rear side of the plane. On the K4, the bottles were located in the left wing, where the 20mm ammos used to be on the previous versions. Why ? Again because the G10/U4 wings needed to be the same as the earlier version while the K4 used a dedicated wing set.

 

Hope this clarifies a bit

 

Vincent

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