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Zoukei Mura - Old Man Blog No.115


Jan_G
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38 minutes ago, Vincent said:

Now, someone is going to ask : why were the MK108 bottles in the wing ammo tray on the K4 and not under the MW50 tank as in the U4.

 

I think the answer is the same to the other question: why was the MK108 housing in the cockpit not the same on the U4 and the K4 ?

 

They were designed by different people who obviously did not bother to talk to each other. The U4 was a WNF creation and only manufactured by WNF while the K4 was a MTT creation. WNF could have, in theory, passed all the drawings to MTT but for some reason it did not happen (or MTT did not bother to use them). So the MK108 setup in the K4 was designed from scratch. This is why for ex the spent cases are ejected out on the K4 but not on the U4

 

There's another possibility : the RLM paid the research work at billed value so doing redesign was in fact financially profitable

 

I don't quite agree with this. First, you're incorrect to state that the K-4 was a Mtt creation, and that design teams at Mtt and WNF did not talk to each other. In fact, WNF was responsible for the development of the new K-series, the redesign being led by Ludwig Bölkow, who at the time was head of the design office in Wiener Neustadt (having come from the design office at Mtt Augsburg). The production office at Mtt Regensburg and ten engineers were subordinated to Bölkow for the task. WNF converted a G airframe into a K prototype late in 1943, and likely built at least one K-2 airframe in 1944 (possibly W.Nr. 600 056). So, while in the end the K-4 was only produced by Mtt Regensburg and Erla Leipzig (limited number of K-4/R6), the primary design of the K-series was done by WNF. So, your explanation for the differences between the G-/U4 and the K-series associated with the MK 108 cannot be down to a lack of communication between Mtt and WNF.

 

Rather, I think there are genuine practical considerations at play. Placing the bottles in the unused ammo tray for the MG 151 brings them even closer to the CoG, and makes them also more easily accessible than when placed under the MW 50 tank. I suspect the reason that this was not done earlier on the G-/U4 may simply be because it would have required too much redesign and/or retooling to relocate the pneumatic lines on an aircraft type that was already in production. It shouldn't be forgotten that, while externally very similar to late AS and D-engined G-series aircraft, the K-series was in fact a major redesign, partially intended to rationalize and simplify production.

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46 minutes ago, Vincent said:

 

I'd really be happy to hear your theory on why the same people designed the same part twice but with differences all over the part. It's been puzzling me ever since I realized that the U4 and the K4 ammo tray/housing are not the same.

 

I would have understood if they incrementally improved the part on the K4 but that's not the case

 

That’s a very good question, and I certainly do not claim to have the answer. However, the MK 108 had a tendency to break its belts, so maybe the redesign of the ammo can was undertaken with the intention to lower stresses on the belt? Or maybe it was just an attempt to somehow simplify construction?

 

Incidentally, you can ask the same question about the rudder pedal linkage in the cockpit: why was this redesigned in the K with respect to the G-/U4?

 

Regardless of the reasons, it’s a fact that the K-series was designed by WNF, just like the G-/U4 had been previously. Hence, any MK 108-related changes in the K must have had a valid technical reason, as WNF was responsible for both the design of the G-/U4 and the K.

 

In addition, the head of the design office at WNF responsible for the design of the K (Ludwig Bölkow) came from the design office at Augsburg, and had the production office and ten engineers from Regensburg assigned to assist him. So, there was clear coordination between WNF and Mtt during the development of the K.

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2 hours ago, Vincent said:

 

?

 

They have the same component numbers on the spare part catalog and look the same on the pictures.

 

They are also listed as the same assembly for both versions here : http://arsenal45-shop.de/product_info.php?info=p389_----rudder-control-unit---messerschmitt-bf109-g10-u4--k4----.html

 

This is a bit of a conundrum. The same part numbers obviously implies that they are the same part. Comparing the K-4 linkages to those of the G-10/U4, they indeed appear identical.

 

However, comparing these to earlier G-/U4 linkages, those to me seem to be different. In this respect, it is important to note that Arsenal 45 explicitly lists the linkages as applicable to the G-10/U4 and K-4 – also implying the earlier G-6/U4 and G-14/U4 were different. Vogt (2012, p. 152 and p. 293-294) further explicitly states that the rudder linkages of the K-4 were different from those of the G-/U4, and were redesigned to save raw materials in their production (K-4 linkages were mainly constructed from sheet steel). Finally, discussing his work on the design of the K-4, Bölkow also mentions that the rudder linkages were entirely redesigned (in Schmoll 2017, p. 172).

 

So, it seems to me that the rudder linkages of the G-6/U4 and G-14/U4 were different from those of the K-4. The reason for the redesign apparently was materials savings. Since production of the G-10/U4 at WNF ran in parallel to K-4 production at Mtt Regensburg and Erla, it seems reasonable that the G-10/U4 would have standardized on the same linkages as the K-4. I’m not at all claiming that this is definitely what happened, but it seems a plausible explanation.

 

References:

Schmoll, P. 2017. Me 109. Produktion und Einsatz. Regenstauf, MZ-Buchverlag. 311 pp.

Vogt, H.H. 2012. Messerschmitt Bf 109 – Einsatzmaschinen – Das Nachschlagwerk. Zweibrücken, VDM Heinz Nickel. 384 pp.

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32 minutes ago, D.B. Andrus said:

As an aside. did the G-6MW/ G-14 have an MW 50 gauge on the port cockpit sidewall similar to the G-10?

 

Thanks,

Damian

 

Yes, all machines equipped with MW 50 would all have had the pressure gauge on the left side of the cockpit just below the sill.

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14 hours ago, Vincent said:

 

You're thinking about the linkages seen in this manual :

 

https://stephentaylorhistorian.files.wordpress.com/2020/04/bf-109g-6-u4.pdf

 

They are the first type, using forged aluminium parts and round rod linkage. It was used on all the G6/U4, G14/U4 and many G10/U4. Then the stamped steel model was introduced to save on labor.

 

13 hours ago, Vincent said:

You know what ?

 

Thanks to this discussion I went to check these rudder pedals linkage in more detail and found out something that escaped me earlier : the early style of linkage is only compatible with the G6 style MK108 housing while the later stamped linkage is only compatible with the K4 style of MK108 housing.

 

So it makes sense now. For some reason, during the G10 and K4 development, the team decided to redesign the MK108 housing AND the linkage. Might be for labor saving or time saving but I suspect it was more about structural function.

 

Of the 2 surviving G10/U4 in the USA, one has the early forged aluminium linkage with G6/U4 MK108 housing (wrknr 610824) while the second one has the K4 assembly (wrknr 610937). Both are coming from the same factory so the change was introduced to all MK108 planes, regardless of the version

 

Thanks a lot !

 

PS: the kit supplies the early forged type with the first version MK108 housing/ammo bin so it is correct for a G6/U4 or a G14/U4 and the G10/U4 up to around wrknr 610824 but if the kit gets declined as a K4 it won't be correct

 

Vincent

 

 

 

Well, it seems we're in agreement then. Thanks for pointing out that early and late styles of linkages were not interchangeable - I had always assumed they were.

 

I think part of the redesign had to do with saving light alloys - a good deal of the changes made to the K-4 centered around replacing light alloys with either steel or wooden parts - e.g. even the wing fillets on many K-4s were laminated wood, as was the seat bucket. In the case of the ammo can, I think the redesign might also have been at least in part related to an effort to make the MK 108 more reliable: this gun was prone to breaking its belts, especially under load, and this problem was never really entirely resolved. If memory serves me well, I seem to recollect that the MK 108 feed in the Me 262 also underwent some redesign for the same reason (but don't quote me on this). 

 

It would make sense for WNF to have used up its existing supplies of old housings/linkages before standardizing on the new design, so it's probably not unexpected to find examples of both the old setup and the revised K-4 arrangement among the G-10/U4, especially in the early production blocks.

 

I do hope ZM or another manufacturer will do a K-4. However, if ZM do one, that will involve some significant retooling, well beyond the MK 108 arrangements!

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5 hours ago, pvanroy said:

I do hope ZM or another manufacturer will do a K-4. However, if ZM do one, that will involve some significant retooling, well beyond the MK 108 arrangements!

 

There is nothing in this kit that is useable on a K-4, maybe the spinner, exhausts, tail wheel, gun sight and the rudder pedals (but not the mechanism). :) Everything will need to be changed. The K-4 is literally a different aircraft, every single part will need a change of some kind, some changes small, some changes radical. 

Radu 

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6 hours ago, Vincent said:

 

Well, that's the downside of wanting to get too detailled. The outside features of the G6/G14 airframes are already a nightmare of little differences so when you add the interior, things go wild.

 

An example : the battery cover behind the headrest is missing the punched side that gives clearance to the 2 cables but the battery itself is missing its bakelite cover that also acts as the retainer strap guide. So the more internals you add...

 

Here's what a G10 battery really looked like :

ww2-german-luftwaffe-sammler_1_a97787861

 

:)

Vincent

 

The photo wouldn't load for me.  Is this the "punched" area you mean?

q3i6Um.jpg

Planes of Fame WNF G-10 battery cover.

 

Cheers,

Damian

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That kind of detail cannot be created in injection-moulded plastic without slide-moulds due to tooling limitations.

Radu

Edited by Radub
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19 hours ago, pvanroy said:

 

Yes, all machines equipped with MW 50 would all have had the pressure gauge on the left side of the cockpit just below the sill.

There was also another position, at least in G-6 with MW50 as described in a British intelligence report about a captured aircraft. I would have to check my sources for details, but I remember that the gauge was installed at a different location since I was doing research about the cockpit of a G-14 for my next book.

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Vincent, after reading the caption of this picture I got curious. What publication is this picture from? I grew up nearby Stuttgart-Echterdingen, where Stuttgart airport is today. Maybe there is a chance to get more information on the place of his "landing", or what has happened?

Sorry for being off-topic here!

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5 hours ago, Vincent said:

Another view of the battery with the bakelite top and the metal retaining band (loose) - note that the fuselage hatch  cutout also had to be modified to make space for the battery. The presence of the extra notch in the cutout is usually a good indication that the plane had the MW50 installed (the ZM kit does not have the correct cutout if you want to display the battery hatch removed but it is correct for a regular G6 without MW50. Of course if you install the hatch, noone will notice the missing extra cutout) :

 

bc6db6fdcaa99daf505a4ffa98a51d1f-copia.j

What a very nice looking specimen of a G-14.   How accurate do you feel the colors are in this profile?   Do you know of any other pictures out there of "Blue 2"?   I'm especially intrigued by the painted out swastika.  Hmmm...  This might be a nice subject to build once the ZM kit comes out.

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