Type IXC accessories

[GlennCauley]

I made a composite drawing of the two guns on the same page... with the same scales that were printed in the book.    (Thank you again, Jon.)

It show the relative sizes of the guns.

However, I am still trying to wrap my head around these dimensions... they just seem too big for the 105 in my opinion.   The gunner braces (U-shaped braces on the sides, 4 of them) are radically different in size on the scaled plans... but in reality would they have been so much larger on the 105?     The circular base plate... I know I keep going back to this... is HUGE compared to the Revell kit base plate on the deck... and to the base plate of the 88.

I am wondering if, in fact, the SCALE of that drawing for the 105 is inaccurate?    That would explain a lot.
If there were some key measurement -- like the full length of the barrel + breech -- that we could get for CERTAIN... that would prove key to unraveling this mystery.
(If indeed there is one.)

[GlennCauley]

Here are some pictures I found of the 105 by doing a Google image search.

The 1st pic shows that the circular base plate did indeed fit on the matching base plate on the deck.   Currently, the Eduard circular base is about 3mm dia. larger than the scribed plate in the Revell kit hull.    (Thought:  Eduard is oversized)

The 2nd pic again shows the circular base fitting inside the scribed plate on the (Revell) deck.   It also show figures for scale.    This seems to indicate that gun/cradle was not massive as what Eduard gun depicts.    (Thought:  Eduard is oversized)

The 3rd & 4th pics show the size of the gun components, compared to men.

[dougie47]

Hi guys,

Getting late so last thing for tonight. I have looked at period photos to estimate the width of the base plates (the outside diameter, O.D.) on real IXs. Photos of U 103 show the base plate equivalent to the width of just under 12 slots. The slots width were the same on IIs and VIIs and I'm pretty sure they would be the same on IXs. Assuming they were, just under 12 slot widths are equivalent to about 15.25mm in 72nd scale. Glenn, the O.D. of the Eduard base plate is 15.5mm, isn't it? If so, then maybe it is okay.
 
I don't know if this helps but the following page gives an overall gun length of 4.74m (65.8mm in 72nd) -
 
http://navweaps.com/Weapons/WNGER_41-45_skc32.htm
 
Cheers,
 
Dougie
 
 

[GlennCauley]

I don't know if the slot sizes are the same on IXC as on other boats.

On the Revell deck the gun mount consists of a 14.4mm square plate, and a 12.3mm circular outline inside of that, presumably where the gun's circular base plate is bolted.

The Eduard circular base plate (15.6mm) is much larger than the deck circle (12.3mm) and it overhangs the square plate.   Period photos clearly show the circular base does not overhang the square plate.

If we were to take the REAL dimension of the gun overall length as 4.74mm (instead of 5.806m on the other plan), and that all other dimensions are proportionally the same as the other plan, then I can calculate a "conversion factor" of 0.8164  (4740/5806) to "correct" all the other dimensions.

See the attached chart below.
I also included the actual dimensions from the RCSubs gun to see which set of dimensions they are closer to.

(And I just vindicated my old math teachers... math actually DOES get used in the real world.  LOL)

[dougie47]

Hi Glenn,

Your maths teacher would have been very proud!
 
Looking at your latest table, which is very helpful, one thing is interesting. If you compare the "True 1:72" column to the "Eduard" column you will see all the figures are very close indeed, close enough to suggest that Eduard might have used the Miroslaw Skwiot plan Jon posted.
 
However, one measurement is quite different - the O.D. of the base. The Skwiot plan indicates 18.5 but Eduard went with 15.5. Why is there a close correlation between all the other figures but a very different one for the base plate? I think I could hazard a guess. The base plate is the one area where one can compare with period photos. If you take a measurement of 18.5mm on the deck of the Revell kit and compare this with deck photos it just looks too big. If they did that then maybe that is why they reduced to 15.5mm?
 
Cheers,
 
Dougie

[GlennCauley]

I am going to prepare a "report" for Eduard, using the information that we have discussed here.    I will post the pics that Jon shared, and see if in fact these were there reference materials for dimensions.   Looking at the period pictures... I am now sure that the scale is too big by nearly 20%.    Nothing says that the line drawings were all perfect, either...  I would be very unsurprised to find the circular base was off.

The pictures clearly show the base should not overhang the square deck plate.   I really do not know how they got that dimension of 15.6 dia for the base... but it too is still wrong.     I feel that likely the Revell boat would have proper dimensions for that plate. (Maybe I'm wrong.)

Also, look at the size difference between the U-shaped gunner braces... between their 10,5 and 8,8 sets.   The size difference is huge.   On the real gun, the sizes of the braces on the different guns should have been fairly similar, yes?

[dougie47]

Hi Glenn,
 
I found what I was looking for, which is a photo showing a side on view where the length of the 10.5cm weapon can be compared with the number of main drainage slots on the hull (which are themselves a known length). I can't give you exact measurements from this method, just an approximation. But comparing this photo of U 123 with sizes in 72nd scale the Eduard gun looks way too big. I wouldn't call this evidence but it is another pointer in the direction of the Eduard gun being too big.
 
Yes, you are right about the gunner's braces. I would think the posterior sizes of the crewmen would not vary and a such we would expect little or no difference in the size of the braces on the 88mm and 105mm.
 
Cheers,
 
Dougie

[GlennCauley]

Here is the report I compiled, and will be submitting to Eduard.

I hope that this prompts them to correct the gun, and re-issue it with the proper dimensions.

[Capt Kremin]

Hi Glenn and Dougie,

Finally found the picture I was looking for and I agree with your measurements more or less, my differences can be covered by photographic measuring errors, with one gun coming out at 64.5mm and another at 66.4mm overall length.

So it would seem that the Skwiot drawings are in error and it's possible that Eduard used his drawings for reference.
It proves the danger of using just one reference source.

Lets hope either Eduard sorts it out or gives Glenn a refund and the proposed CMK 10.5cm is correct, or all 3.

Regards
Jon

[GlennCauley]

Thank you for the confirmation, Jon.

May I ask that people here bring this issue to the attention of Eduard, so that I am not the lone voice crying out in the dark?
I have already logged a support issue, sent that report, and referenced these threads.
It would certainly help if others did likewise.

Cheers!
Glenn

[dbauer]

Hi All!
This indeed makes for interesting reading!  I have the 105 from RC Sub. I should be receiving the Eduard version any day now.  Would it be possible to kit bash both to make  a suitable deck gun? Just a thought.
Regards,
Dan

[GlennCauley]

Oh Dan Dan Dan... you have NO idea how disappointed I was to find out the Eduard gun was waaaayyyy too big.  The detail on it is simply beautiful. 
I had thought of the same thing as you... to kitbash.  Unfortunately, since the Eduard gun is roughly 22% too big, I doubt there are any parts that are useful to use on the RCSubs gun.

On another note, I heard back from Eduard support:

"Thanks for letting us know about this issue and for elaborating the details for us.
I've already passed your message to our Brassin development department. Our guys will look into this and decide, whether or not there's a mistake to fix.
If we want/need your further support, we'll get in touch with you.
Thanks again for your support!
Libor Havranek"

Uhmmmm...... I am not sure I like the choice of words....... "whether or not there's a mistake to fix."
There IS a mistake... a "22% too big" mistake...   
I hope that they take responsibility for the error, so that they can move on and re-issue the kit, properly sized.

Again, I am calling on the good people here (who know their stuff) to lodge a complaint with Eduard... so they don't think I'm just some lone crackpot whistleblower type.   

[Capt Kremin]

Hi Glenn, I am mobile this week so my facilities are limited. I will put something together on the weekend.
Regards
Jon

[GlennCauley]

Thank you, Jon... every little bit helps, and more voices are hard to disregard.

I heard from another long-time U-boat modeller on another forum -- Grauwolf -- who mentioned that the gun cradle was the same between the 88 and 105 guns... only the barrel changed.   He also says the Eduard gun is definitely oversized.

[Capt Kremin]

Hi Glenn,
I thought that about the mount, but I believe there are a couple of minor differences IIRC the 8.8 mount is an SKC35 and the 10.5 is an SKC36. I could be wrong on the actual numbers, I have no reference works with me.
Regards
Jon