Bf 109 Tail plane root

[pvanroy]

On 10/6/2022 at 9:47 AM, Radub said:

Can you please post here a scan of that document? I am sure that others would like to see it too. There are plenty of photos (more than "Black 6") that I posted here showing that the distance is MORE, MUCH MORE, than 1.75 mm. (...)

 

On 10/6/2022 at 11:47 AM, Radub said:

(...) I have many manuals for many versions of the Bf 109 and I cannot find any reference for any specific distance between the flange and fin/fuselage, no number is specified anywhere, it is as if they could not care less. 

Actually there is no mention of any "flange adjustment" in any manual. (...)

 

(...) I looked at all the documentation I have, and I have a lot, and I cannot find any reference to the distance between the flange and the fin/fuselage. Pvanroy said he had it, so I am looking forward to it. 

Radu

 

So, I just realized that I actually have a PDF of the 1942 edition of D. (Luft) T.2109/Rep. saved on my computer right here. I don’t want to have another turn on this merry-go-round, but since Mr Brinzan earlier twice expressed great interest in seeing an original Messerschmitt document specifying tolerances for the gap between the fin and stabilizer, with some trepidation, I’m posting the relevant information here.

 

D. (Luft) T.2109/Rep. is the general repair manual I for the Bf 109, and at the time of publication, was valid for all series up to the G. An introductory remark specifies that for items specific to the G, further documents will be issued later, but that all general repair guidelines and provided examples are equally applicable to the G as they are to earlier series. So, while the diagram specifying the tolerances for the gap between fin and stabilizer shows an earlier braced tailplane, these tolerances are equally applicable to the F and the G series (also note that the earlier A-E series too had a very narrow flange of upturned skinning at the base of the stabilizer).

 

Now, as to the tolerances for the gap, D. (Luft) T.2109/Rep. (p. III 10 of Chapter III) provides no minimum value, which is logical, considering that the smaller the gap is, the better, as long as the tailplane can move unimpeded for trimming. The maximum permissible value is given as 1.5 mm. For those of you who would like to see a scan of the original, I have uploaded an extract of the relevant pages here (tolerances highlighted):

 

D. (Luft) T.2109/Rep. page III 10

 

This, of course, means that the measured width of up to 10 mm for the gap on Black 6, as reported by Mr Brinzan, is approximately 6.7 times greater than the maximum value permitted according to original wartime Messerschmitt documents. The reason why such an out-of-tolerance gap was permitted on Black 6 likely has to do with the fact that, during its airshow days, it was a display warbird, being operated under very strict flight and performance limitations. The flanges are neither structural nor flight-critical elements, and, within certain performance limits, you could likely fly the aircraft safely without them even fitted, just like you could in principle fly e.g., without spinner, undercarriage covers or even cowling (in fact, the He 280 V2 flew without engine cowlings, and the Bf 109 J / HA-1.109-JL prototype had the side panels of the cowling removed on its test flights). However, doing so will rob you of a lot of performance, and force the aircraft to be operated under restrictions. The whole point of all these fittings was to limit drag as much as possible, and on an operational airframe the performance penalty incurred as a result of lax tolerances would be entirely unacceptable (training airframes may have been treated in a more relaxed manner). Hence, the strict wartime tolerances dictated by Messerschmitt. On the other hand, during its display days, Black 6 was not an operational fighter aircraft anymore, but a very severely restricted piece of flying heritage. Hence, adhering to strict tolerances for drag-reducing fittings like the tailplane flanges was much less of a concern, and the restoration crew likely decided to use the old, somewhat beaten-up and out-of-spec flanges instead of newly manufactured parts out of considerations of authenticity.

 

Most sheet metal used in skinning on the Bf 109 had a thickness of 0.75 mm. If we add this to the maximum allowable gap of 1.5 mm, we get a maximal permissible distance between the fin and the outer surface of the flange of 2.25 mm.

 

For the ZM kit, this means that the depiction of the flange (circa 9.6 mm in scale, as reported by Mr Brinzan) is approximately 4.3 times overscale for a wartime operational aircraft. I want to stress again that this is an absolutely minor issue, that can easily be rectified for anyone inclined to do so. And from the photos of the kit tailplane posted by Mr Brinzan, it seems clear that even without correction, the end result will look more than acceptable. So, I really hope no-one is going freak out over this tiny glitch, and we can just leave it here!!!

[CRAZY IVAN5]

11 hours ago, Radub said:

Here are some photos that I took this morning. I invite all of you who have to kit to do the same things that I am going to show in the next photos. 

 

So, let us start.

This is the distance between the top edges of the flanges. As you can see on the calliper screen, the distance is 4.30 mm. 

 

This is the width of the fin. As you can see on the calliper screen, the width is 3.70 mm. 

 

So, simple calculation, 4.30-3.70=0.6 mm. Divide by two and that means that the width of each flange is 0.3 mm. What is 0.3 mm? 0.3 mm is the width of a regular business card. In this photo I used the calliper to measure the thickness of a business card. 

 

Now, I placed the business card on the fin, on top of the flange. You can see that the flange is actually slightly thinner than the card in this particular spot. Note that this is the widest spot on the flange, it is slightly thinner at the back.

 

Here is a photo of the tailplane attached to the fuselage. Those of you who remember the photos of the flyable aircraft posted earlier in this thread may be able to spot the similarity. 

 

Some of you will say "Wait a minute, that is not what we were shown in the photos posted elsewhere."

There are two things going on there:

Thing 1: Let us remember that when the first complaints about the flange were posted on the internet, they came from people who did not know that the flange was supposed to stand proud of the fin/fuselage. To them any "step" was a "problem", a noticeable "step" was a noticeable "problem". But here is the crux of the issue: a "step" is not a "problem", it is a "feature". I think that that very many photos of the flyable aircraft I posted in this thread demonstrated clearly that the flange does indeed stand at quite a distance from the fin/fuselage. 

Thing 2: I can replicate the "problem" with lighting and angle. 

From this angle the lighting creates a shadow that exaggerates the joint line and makes the flange look huge.  

 

This is the part turned around. It changed again. 

 

here is the part photographed from above, which really shows the true thickness of the material. 

 

Here is a photo from the back: 

 

So, that is it, a 0.3 mm (less in some places) flange in scale 1/32. In real life that is 0.3 x 32 = 9.6 mm. That is just shy of 10 mm. Take a metric ruler. Look at 10 mm. Then look at the photos of the flange on the flyable aircraft shown in this thread. You make up your own minds. 

I hope this helps. 

Radu 

That is exactly the way the tail panes fit on my kit.  I thought to myself , well, that's not the worst I've had to deal with , granted , this section could've been engineered better but I'll deal with it. Just a few swipes with some sand paper [ carefully!] will set things straight . I believe Z-M may want to do some re-engineering before they issue out the other versions , just a thought Also Radu thankyou for all the info that you've imparted , I'm learning a lot 

[Radub]

10 hours ago, pvanroy said:

 

 

Now, as to the tolerances for the gap, D. (Luft) T.2109/Rep. (p. III 10 of Chapter III) provides no minimum value, which is logical, considering that the smaller the gap is, the better, as long as the tailplane can move unimpeded for trimming. The maximum permissible value is given as 1.5 mm. For those of you who would like to see a scan of the original, I have uploaded an extract of the relevant pages here (tolerances highlighted):

 

D. (Luft) T.2109/Rep. page III 10

 

Pvanroy,

As the text in your document clearly explains, the figures shown indicate "tolerance" not "clearance". The text for the ailerons reads: "spalt darf ± 2 mm über zeichn. gemaßes Mäß sein", which means "Gap may deviate ± 2 mm from drawing within reason". This literally means that the allowable deviaton from the drawings is plus/minus the indicated amount in the chart. Of note is the ± sign, which means plus/minus. If those figures were to indicate "clearance" (the distance between parts), the ± sign would mean that the part could go "plus" as well as "minus" from the surface, which in the case of the flange could LITERALLY also put the flange UNDER the skin of the aircraft. 

The points I richly illustrated in this thread still stand. I refer again to the many photos of the real aicraft, including the superb photo posted in the thread by RBrown showing the gap between the flange and the fin/fuselage on the relatively pristine Bf 109 perserved in the Treloar Centre in Caberra, which is neither "damaged" nor "restored". Even from that distance the gap is clearly visible. 

Radu 

Edited October 8, 2022 by Radub
spelling

[Gazzas]

20 hours ago, Radub said:

Here are some photos that I took this morning. I invite all of you who have to kit to do the same things that I am going to show in the next photos. 

 

So, let us start.

This is the distance between the top edges of the flanges. As you can see on the calliper screen, the distance is 4.30 mm. 

 

This is the width of the fin. As you can see on the calliper screen, the width is 3.70 mm. 

 

So, simple calculation, 4.30-3.70=0.6 mm. Divide by two and that means that the width of each flange is 0.3 mm. What is 0.3 mm? 0.3 mm is the width of a regular business card. In this photo I used the calliper to measure the thickness of a business card. 

 

Now, I placed the business card on the fin, on top of the flange. You can see that the flange is actually slightly thinner than the card in this particular spot. Note that this is the widest spot on the flange, it is slightly thinner at the back.

 

Here is a photo of the tailplane attached to the fuselage. Those of you who remember the photos of the flyable aircraft posted earlier in this thread may be able to spot the similarity. 

 

Some of you will say "Wait a minute, that is not what we were shown in the photos posted elsewhere."

There are two things going on there:

Thing 1: Let us remember that when the first complaints about the flange were posted on the internet, they came from people who did not know that the flange was supposed to stand proud of the fin/fuselage. To them any "step" was a "problem", a noticeable "step" was a noticeable "problem". But here is the crux of the issue: a "step" is not a "problem", it is a "feature". I think that that very many photos of the flyable aircraft I posted in this thread demonstrated clearly that the flange does indeed stand at quite a distance from the fin/fuselage. 

Thing 2: I can replicate the "problem" with lighting and angle. 

From this angle the lighting creates a shadow that exaggerates the joint line and makes the flange look huge.  

 

This is the part turned around. It changed again. 

 

here is the part photographed from above, which really shows the true thickness of the material. 

 

Here is a photo from the back: 

 

So, that is it, a 0.3 mm (less in some places) flange in scale 1/32. In real life that is 0.3 x 32 = 9.6 mm. That is just shy of 10 mm. Take a metric ruler. Look at 10 mm. Then look at the photos of the flange on the flyable aircraft shown in this thread. You make up your own minds. 

I hope this helps. 

Radu 

 

Why do you keep defending it?  It looks like ****, no matter what the rationale.    Flat shelves and vertical block-like structures do not belong on a sleek aircraft.  Might as well buy a LEGGO kit and try to pass it off as an accurate representation.

[Radub]

Not "defending". Explaining. I am sure that the majority of reasonable people understand it by now. 

Radu 

[Gazzas]

4 minutes ago, Radub said:

Not "defending". Explaining. I am sure that the majority of reasonable people understand it by now. 

Radu 

 

You're telling them its potentially "right" when anyone can see it's plainly wrong, out of scale, and ugly.

[Radub]

2 minutes ago, Gazzas said:

 

You're telling them its potentially "right" when anyone can see it's plainly wrong, out of scale, and ugly.

 

"Facts" will aways win over "opinion". Read the thread. 

Radu 

[pvanroy]

1 hour ago, Radub said:

 

Pvanroy,

As the text in your document clearly explains, the figures shown indicate "tolerance" not "clearance". The text for the ailerons reads: "spalt darf ± 2 mm über zeichn. gemaßes Mäß sein", which means "Gap may deviate ± 2 mm from drawing within reason". This literally means that the allowable deviaton from the drawings is plus/minus the indicated amount in the chart. Of note is the ± sign, which means plus/minus. If those figures were to indicate "clearance" (the distance between parts), the ± sign would mean that the part could go "plus" as well as "minus" from the surface, which in the case of the flange could LITERALLY also put the flange UNDER the skin of the aircraft. 

The points I richly illustrated in this thread still stand. I refer again to the many photos of the real aicraft, including the superb photo posted in the thread by RBrown showing the gap between the flange and the fin/fuselage on the relatively pristine Bf 109 perserved in the Treloar Centre in Caberra, which is neither "damaged" nor "restored". Even from that distance the gap is clearly visible. 

Radu 

 

Mr Brinzan, you clearly don’t understand the technical document I posted. The drawing with the +/- 2 mm tolerance you refer to is clearly indicated as pertaining to the ‘Querruder und Klappe’, i.e. ailerons and flaps, so it has absolutely no bearing on the current discussion.

 

The next drawing, which is germane to this discussion, is identified as pertaining to the ‘Leitwerk’, or tail. Here are the minimum and maximum dimensions of the gaps noted, these are the permissible ranges for the gaps, not tolerances on these ranges (as an aside, does it make sense to specify maximum and  minimum tolerances for the size of a gap?).

 

Since you don’t seem to understand technical documents, I’ve added the preceding page III 09 from the repair manual, which explicitly states:

 

 “The maximum and minimum dimensions for these gaps, which have to be maintained when replacing parts, are to be found in drawings and tables 45a through d.”

 

Link to the original here (relevant parts highlighted):

 

D. (Luft) T.2109/Rep. page III 09-10

 

The drawing/table relevant to the tail is 45d, with no specified minimum, and a maximum allowed width of 1.5 mm for the distance between the fin and stabilizer. I hope this clarifies things, and you are now able to understand the purpose and meaning of the drawings and table I shared earlier.

 

Please, Mr Brinzan, for your own sake, stop arguing with original Messerschmitt technical documentation that was formally approved and issued by the RLM. You’re really not doing yourself or your credibility any favors.

 

Edited October 8, 2022 by pvanroy
Highlighting text in boldface and italic

[Radub]

There is another discussion on another forum where a self-appointed expert keeps telling everyone quite agresively that we MUST NOT take Luftwaffe drawings as gospel and that we need to find the "additional correspondence" and the actual drawings used in the factory which are full of "red pencil corrections" made locally. I will not go there, not my fight. Secondly, I never claimed anywhere that I am some kind of "expert" on the Bf 109 (or anything else for that matter) so please stop trying to "expose" me. I am a modeller, I work with what I got. And what I got is knowledge about injection-moulded plastc tooling. I can tell you (without attempting to put into question your intellect or knowledge) that it is not technically possible to represent a 1.5 mm item in real life in scale 1/32. Even if we were to add the 0.75 mm for the metal, a total of 2.25, in scale 1/32 that is 0.07 mm (medium thickness of human hair) which is not a thing that can be achieved with any injection-molded plastic tool. Any item has to be at least 0.1 mm to be visible under a magnifier, but preferrably more than that to be seen with the naked eye. For example the finest rivet that you can see on the best models are around 0.15 mm - it is possible to make smaller but it is hard to achieve consistency. Panel lines are around 0.15 for the finest but usually 0.2 mm wide. Any item standing "proud" from a surface (such as an overallping panel, has to be at least 0.15 mm to show up, but preferrably more than that to look "right" - most raised surface panels are at 0.2 to 0.3 mm to convince the eye. A 0.3 mm flange on a bf 109 is not beyond the expected industry standards. All models are about compromise. Every model has to exagerate any detail that is visible or eliminate any detail that is too small. Models are not "academic papers", they are "entertainment", just illusions of reality in small scale. 

Anyway, I stand by the many photographs shown in this thread. People can make up their own minds. 

Radu 

 

Edited October 8, 2022 by Radub

[thierry laurent]

Exactly. As I already wrote models are full of technical compromises. They depict reality with as much as possible accuracy but they are not perfectly scaled items. In spite of technical progress, this is simply impossible with injected plastic. Nonetheless, this does not mean that in some cases, other design choices could not have been made. I received the 109 as well as the P-40 yesterday and both kits are absolute marvels. I could not prevent smiling when we are cutting hairs in four parts regarding that 109 tail as I'm now building kits for which some technical design choices will prevent many modellers to get an acceptable result or simply end the assembly. Believe me, THAT is noticeably different...

[pvanroy]

48 minutes ago, Radub said:

There is another discussion on another forum where a self-appointed expert keeps telling everyone quite agresively that we MUST NOT take Luftwaffe drawings as gospel and that we need to find the "additional correspondence" and the actual drawings used in the factory which are full of "red pencil corrections" made locally. I will not go there, not my fight. Secondly, I never claimed anywhere that I am some kind of "expert" on the Bf 109 (or anything else for that matter) so please stop trying to "expose" me. I am a modeller, I work with what I got. And what I got is knowledge about injection-moulded plastc tooling. I can tell you (without attempting to put into question your intellect or knowledge) that it is not technically possible to represent a 1.5 mm item in real life in scale 1/32. Even if we were to add the 0.75 mm for the metal, a total of 2.25, in scale 1/32 that is 0.07 mm (medium thickness of human hair) which is not a thing that can be achieved with any injection-molded plastic tool. Any item has to be at least 0.1 mm to be visible under a magnifier, but preferrably more than that to be seen with the naked eye. For example the finest rivet that you can see on the best models are around 0.15 mm - it is possible to make smaller but it is hard to achieve consistency. Panel lines are around 0.15 for the finest but usually 0.2 mm wide. Any item standing "proud" from a surface (such as an overallping panel, has to be at least 0.15 mm to show up, but preferrably more than that to look "right" - most raised surface panels are at 0.2 to 0.3 mm to convince the eye. A 0.3 mm flange on a bf 109 is not beyond the expected industry standards. All models are about compromise. Every model has to exagerate any detail that is visible or eliminate any detail that is too small. Models are not "academic papers", they are "entertainment", just illusions of reality in small scale. 

Anyway, I stand by the many photographs shown in this thread. People can make up their own minds. 

Radu 

 

 

1. I’m not an expert, and I never claimed to be. I just happen to have fairly extensive documentation on the Bf 109, including a large part of technical manuals.

 

2. There may indeed be differences between parts produced, and their original design drawings, which indeed quite often got modified afterwards, with notes identifying changes scribbled by hand on them. However, that’s of no relevance here, as the document I provided is an official, RLM-issued repair manual, not an engineering/design document. This technical manual sets out the exact mandatory procedures, techniques, materials and tolerances that needed to be followed when making repairs. Whenever changes were made, an updated edition of these manuals was issued.

 

3. I’m not trying to ‘expose’ anyone. You asked me twice to provide an official technical document that specified dimensions for the gap, and I did just that. When you didn’t like what the official documentation you asked for showed, you were the one who  – bizarrely – started arguing against it.

 

4. This discussion came about because you kept insisting that the wide gaps shown by Black 6 are  normal and within specification, which has now unequivocally been demonstrated is not the case. This is also supported by all the other images of other aircraft, both in this thread and elsewhere, which consistently show a much tighter fit of the flanges than shown by Black 6. So, no matter how you look at it, in this respect, Black 6 is a bit of an outlier.

 

5. As a corollary of this, the flange as depicted by the ZM kit is slightly overscale. I totally understand the technical reasons for this, and have repeatedly stated that it is absolutely not a big issue. The problem arose when you kept insisting that the rendition of the flange in the ZM kit was spot on, while, in fact, it is slightly overscale. Given the absolute triviality of the matter, and the molding-technical justifications for it, I really don’t understand why it is so difficult to simply admit this.

 

6. The official technical documentation specifying the permissible gap sizes and a load of photographs are now all available in this thread. Anyone who cares about this arcane matter can now look at all this information and make up their mind about the issue themselves.

 

7. I'm taking a break from this, this is getting tedious. For god's sake, it's a tiny flange on a plastic scale model!

[Radub]

25 minutes ago, pvanroy said:

The problem arose when you kept insisting that the rendition of the flange in the ZM kit was spot on, while, in fact, it is slightly overscale. Given the absolute triviality of the matter, and the molding-technical justifications for it, I really don’t understand why it is so difficult to simply admit this.

 

 

This is an OUTRIGHT LIE!!! This thread was always about the real aicraft and I tried really hard NOT to mention the ZM kit. I only mentioned the ZM kit in the end, after YOU brought up some outrageously huge dimensions on which YOU then you porceeded to create a scaffolding of outrage. This is what YOU said "on the ZM kit, the flange sits around 25 mm in scale proud of the fin, which is clearly excessive; I at least have never seen any actual airframes, or photographs, documenting a 25 mm gap."
For those who are late to this discussion, this is what I am talking about: 

 

Only after you posted your erroneous statements about the ZM kit and your made-up dimenions I showed photos of what the model looks like in reality without any statements about it being right or wrong. These are just facts, read the thread. Others, especially YOU, made a big fuss about the ZM kit so please stop blaming me for other people's actions or your actions. 
I continue to insist (and please read this carefully!) that the photos of the real aicraft posted in this thread speak for themselves. 

Radu 

Edited October 8, 2022 by Radub

[thierry laurent]

I think that topic should be closed...

[Radub]

3 hours ago, thierry laurent said:

I think that topic should be closed...

Agreed! That should have happened the second when the discussion was made about me rather than the Bf 109.

Radu

Edited October 8, 2022 by Radub

[pvanroy]

9 minutes ago, Radub said:

 

This is an OUTRIGHT LIE!!! This thread was always about the real aicraft and I tried really hard NOT to mention the ZM kit. I only mentioned the ZM kit in the end, after YOU brought up some outrageously huge dimensions on which YOU then you porceeded to create a scaffolding of outrage. This is what YOU said "on the ZM kit, the flange sits around 25 mm in scale proud of the fin, which is clearly excessive; I at least have never seen any actual airframes, or photographs, documenting a 25 mm gap."
For those who are late to this discussion, this is what I am talking about: 

 

Only after you posted your erroneous statements about the ZM kit and your made-up dimenions I showed photos of what the model looks like in reality without any statements about it being right or wrong. These are just facts, read the thread. Others, especially YOU, made a big fuss about the ZM kit so please stop blaming me for other people's actions or your actions. 
I continue to insist (and please read this carefully!) that the photos of the real aicraft posted in this thread speak for themselves. 

Radu 

 

Ok, my final intervention in this thread, I too think it really has run its course. 

 

First, the 25 mm statement was NOT made by me, it was made by Gazzas, and I just quoted him.

 

Second, I didn't 'create a scaffolding of outrage' - I've constantly said it was an extremely minor issues, and by everything I have seen, the kit looks exceptional.

 

Signing off now.