U-552 by yvesvidal - FINISHED - Trumpeter - 1/48 - PLASTIC - Type VIIC U-boat

[yvesvidal]

Decals are included with the kit.

 

Yves

[yvesvidal]

Our next efforts are focused on the Rear torpedo tube, electric compressors and torpedoes compensation tanks. A summary of the stern tanks seems on order to explain the rear compartment: 

The Trumpeter kit provides one of the compensation tanks (2.35 tons of salt water), one electric compressor and the torpedo tube. Once again, it is very spartan and it is regrettable that no additional parts are provided in the kit, as these two components would not detract the viewer from the intricacies of the compartment.

 

Below is a picture of what we are talking about, from the U-995 submarine. The large compressor sits on top of the torpedo compensation tank. The torpedo tube is visible on the left of the picture. To the extreme left is the other diesel compressor installed on the U-995, sitting on the other compensation tank. Not visible, to the right of the torpedo tube is a large canister containing mines and other "goodies" that can be launched using the ejection tube. Underneath the metal floor, is the torpedo stowage area for one eel, sitting right between the two electric motors.

On the early Type VIIc units, there was two electric compressors. The German engineers replaced the starboard electric compressor later on by a diesel unit, as the electric consumption was way too important with both electric compressors. It is not clear if U-552 has two electric or a combo electric/Diesel compressors.

 

From the manual: 

 

a) Electric air compressor.     The compressed air required for blowing ballast tanks, starting diesel engines, for torpedo launching installation, anchor installation and so on, is produced by two electric, 4-stage air compressors, located in the aft torpedo room.

Their performance is 6.1 liters/minute at 205 kg/cm².     Compressed air from each stage is cooled down in a cooler.  The air cooler and lubricating oil cooler are located in one case outside the compressor.  The compressor is cooled by sea water.  The two-stage cooling water pump is located on the coupling side of compressor and is driven by means of helical gears from the crankshaft.  The gear type lubricating oil pump is located on the front side of compressor at its base plate and is driven from the crankshaft by means of gear wheels.     The compressor is driven by a direct current, shunt electric motor, with starting compound winding on commutating poles.  The motor is splash-proof and self-cooled with air.         b) Diesel air compressor.     Type VIIC U-boats since Boat No. ____ are provided with one electric air compressor and one diesel air compressor.     The diesel air compressor is a horizontal, double piston, two-stroke diesel engine with free pistons which are directly coupled with a four-stage compressor.  Its performance is 8.5 liters/minute at 205 kg/cm².     After compression the air from each stage passes through a condenser for cooling.  The cooler for all four stages is located beneath the compressor in individual cases.  The air is cooled by means of sea water.  The cooling water pump, rotary vane type, driven by a gear shaft, forces the water in the following order:  cooler IV, combustion chamber cooling jacket, compressor stage I, compressor stage IV, cooler III, compressor stage III, compressor stage II, cooler I, cooler II.     The lubricating oil pump, driven by means of an eccentric from the gear shaft, lubricates all sliding parts.     The compressor is driven by two-stroke diesel engine made by Junkers, with two opposed pistons,

which are coupled together by means of two sets of traverses, two gear racks with a geared wheel located between them.  Engine pistons control intake of air, which is compressed and exhausted.  The stage I compressor piston is connected with left engine piston, the stage II compressor piston is connected with right engine piston.  The stage IV compressor piston is coupled with the left piston rack and the stage III compressor piston is coupled with the right piston rack.  The compressor is started by means of compressed air admitted to particular compressor stage chambers.     The compressor casing is splash-proof.         c) High pressure compressed air flasks.     Compressed air is stored in 12 high pressure air flasks with total capacity of 3.900 m3.  Each flask has capacity of 325 liters and is tested at pressure of 280 at.  The flasks are grouped in 6 banks (2 flasks each), which are located as follows.     Bank 1 Upper deck aft, on both sides of the aft external torpedo container Bank 2 Upper deck, above the diesel engine assembly patch Bank 3 Petty officer's room port and stb. Bank 4 Forward torpedo room to port Bank 5 Forward torpedo room to stb. Bank 6 One flask in the bow buoyancy tank, one flask on the stb. side forward of the external torpedo container.     The flasks are smooth shaped and are lined with lead.  On both ends they narrow into the neck, capped by means of flange and cover.  To drain the flask a drainage pipe is provided in the deepest point of flask.  Furthermore, the flasks are inclined 4 degrees from the horizontal.   Yves

Edited June 7, 2019 by yvesvidal

[yvesvidal]

The Electric Compressor, pimped up a little bit. It should be a four stages compressor, but Trumpeter forgot the second cylinder.... 

The Rear torpedo tube on its platform and the canister containing the mines: 

Finally, the electric panel to control the propulsion motors: 

Lots of detail remain to be placed and painted.

 

Yves

Edited June 13, 2019 by yvesvidal

[yvesvidal]

Still working on the rear compartment. Installation of the LEDs: four of them connected in series. That should give us close to 10.8 Volts: 

The electrical compressor is pretty much done: 

Yves

[yvesvidal]

Moving along: 

One can clearly see the torpedo compensation tank. Unfortunately, Trumpeter only gave one in the kit, leaving plenty of open space on the side. Such a pity!

Yves

Edited June 8, 2019 by yvesvidal

[yvesvidal]

While I am blocked on the rear compartment, I have decided to go back to the deck and glue some PEs. I just finished the second part of the deck with these countless hinges to glue carefully. They are about the size of a pin head (or slightly bigger) and are a challenge to place correctly aligned: 

This is my first attempt at using PEs and I am so glad a nice coat of primer and paint will cover the rather sloppy job I did. It will harmonize everything and hide a lot of imperfections.

 

Yves

[J11]

8 hours ago, yvesvidal said:

Moving along: 

One can clearly see the torpedo compensation tank. Unfortunately, Trumpeter only gave one in the kit, leaving plenty of open space on the side. Such a pity!

Yves

I don't mean to photo bomb your blog. I thought it would be  interesting comparison for the modern torpedo tubes and the first American test torpedo tube which was called "What is it" because of the secrecy as the American public saw it on the Naval docks late in the civil war. I have completed the first model of phase one testing box and will take a few more months to work out phase two of the actual launch tube as shown in the images. Also imaged is the first torpedo design made from oak wood if you can imagine that. 

 

Construction phase:

Finished model phase one:

Author, Mr. Veits illustrations from his book:

Phase two of test torpedo tube:

Your work is masterfully exquisite on your sub and apologize again for all the images for a comparison of CW developmental and U class sub torpedo tubes. Look forward to more of your build images and technics in construction.

 

 

Edited June 9, 2019 by Jonathan11

[yvesvidal]

Thank you Jonathan. I believe your project deserves a Build Log in itself. Very interesting early concept for a torpedo launcher.

 

Moving to the part "C" of the deck and mot likely the most difficult due to the anti-skidding  plates around the gun: 

Once again, kudos to RCSUBs for their impeccable photo-etched brass kit with excellent explanations and a few spare parts: 

Not perfect and I cannot wait to see how it will look like with a coat of primer on top.

Yes, much better. At least I can see where some small imperfections are located and sand them carefully. That hull is starting to look like a TYPE VIIc.

 

A few more details: 

Yes, the area around the gun looks pretty neat once coated. And the numerous hinges are correctly aligned for the most part.

I hope you are enjoying....as much as I do :-)

 

Yves

 

 

[lmagna]

2 hours ago, yvesvidal said:

I hope you are enjoying....as much as I do 🙂

That is without a doubt. And I'm not even much of a type VII U-Boat fan.

[Old Collingwood]

I agree with Lou  - Facinating.

 

OC.

[mtaylor]

Jonathon,

By all means a build log for your "What is it".  

 

Yves,

Looks spectacular from here.  

[J11]

Be glad too. I'll get the images correlated and post one up by next week. But it has been on the back burner as the Alabama has taken precedent for now. The second phase launch tube is a problem in working model logistics as per how they loaded the torpedo into the tube and the mechanisms used.

Edited June 10, 2019 by Jonathan11

[Tigerdvr]

Outstanding log, thanks for sharing.

 

 

Harley

 

[yvesvidal]

Moving along with Deck D, right behind the conning tower: 

I am not letting the brass pieces, time to oxidize: 

Two more sections of deck and we will be done: 

The primer used is a can for automotive painting. Works very well on clean brass parts. You will agree with me that this deck is a nice and radical departure from the Trumpeter plastic molded deck. I am not regretting a single second, the efforts (and money) invested in that RCSUBs deck.

 

Yves

Edited June 12, 2019 by yvesvidal

[yvesvidal]

Do you believe in Miracles and co-creation?

 

As some of you who are following this saga may know, I have been in search for some spare parts and sprues for this rare model. I want to be able to duplicate certain components of that huge model to make it more attractive and interesting.

 

My attempts at contacting Trumpeter (through Joanna, their sales rep in China and even the local distributor in the USA) were crowned by a complete lack of response and interest for my requests. Obviously, once you buy the kit, you are on your own and Trumpeter will not help you. I have dealt with other plastic models companies in the past (Italeri and Heller) and they have always been responsive. Trumpeter is way too big to take care of a remote and obscure customer in the far land of America. 

 

And then the miracle happened, when I had given up and started building painstakingly some parts myself: 

Being subscribed to the Nautilus Drydocks newsletter, I received one day a presentation of the Trumpeter U-552 model recently completed for a customer. The model was exquisitely finished but did not show any interior details. It was basically built as a regular model, with the hull and conning tower. I decided to contact the owner of the Nautilus Drydocks and inquired if he would be willing to sell me some spare parts for the rear compartment and engine compartment. He counter-offered by telling me that I could get all the parts left over from the build for an unbeatable price.

Today, I just received the complete set of parts allowing me to literally build a second interior with all the compartments. Truly a miracle and the proof that we can co-create what we want if it goes along with the desires of the Universe. This will allow me to build the second electric motor and many other things making this model, hopefully better and more complete than what Trumpeter intended.

 

A very grateful THANKS to Bob from the Nautilus Drydocks for allowing me this unique opportunity.

 

https://www.rc-submarine.com/

 

This link will take you to Bob Martin's web site. Here you can enjoy some of the magnificent models, Bob has been realizing: 

https://www.rc-submarine.com/copy-of-gallery

 

Yves

 

 

Edited June 13, 2019 by yvesvidal

[CDW]

What a fortuitous find! Indeed, this must be your lucky day. Well deserved with all that beautiful work you've been doing on this build. I am happy for you.

[mtaylor]

Congratulations.  I guess there is a Santa Claus even in June.

[J11]

The true modeler's treasure hunt!  Congratulations!

[yvesvidal]

Alright, a little bit of de-construction. Dubz used to do that a lot on his "better-than-perfect" Syren model.

I just unglued the three frames I had built, filed the main keel and will be gluing back the Trumpeter parts. Below are some of the "spare" parts I will be using for that rear torpedo compartment: 

Yves

 

Edited June 17, 2019 by yvesvidal

[lmagna]

Congratulations on getting the parts you so needed to do this build the way you wanted.

 

I think I know how you feel in a way. I was settled on taking a model of the USS Indianapolis and converting to to hopefully something close to the USS Houston when I found a model of a long discontinued Houston available. Really made my day, even though it did cost me a bit.

[yvesvidal]

Little progress, reconstructing: 

Yves

[yvesvidal]

Part E of that long deck: 

We are soon running out of PE parts....which is a good feeling.

One more section to go.... But it will wait, as there are far too many delicate parts to glue on it.

 

Yves

Edited June 15, 2019 by yvesvidal

[yvesvidal]

Trying to finish the rear compartment. It is by far the most difficult to realize and set in location. One of the reasons is that I am trying to make it more complicated than it was designed for. The second reason is that I am trying to power the shafts and allow the propellers to rotate. Finally, the capability to take apart and insert the starboard half-hull makes all the assembly very tight and delicate. A lot fo sanding has to take place to allow the insertion of the half-hull in the main hull.

I think that once I put together the entire rear compartment, I am going to glue it (with just a couple of points) to the main hull and get the shafts coupled permanently. It is necessary to file the main bulwark to allow the insertion of the cover-hull: 

Lots of complexity for not much additional results. We will see how this goes.

 

Yves

[CDW]

12 minutes ago, yvesvidal said:

Lots of complexity for not much additional results. We will see how this goes.

 

Yves

I disagree Yves. The results look spectacular. All the hard work you're doing is paying dividends.

[lmagna]

1 hour ago, yvesvidal said:

Lots of complexity for not much additional results. We will see how this goes.

I also disagree Yves.

By adding the additional parts and showing how must stuff is really inside the pressure hull and how cramped it really is you will project the true nature of just how small the type VII really was, especially when you consider how much crew had to live and work in these quarters for weeks on end and sometimes in pretty foul weather conditions. Can you guess how hard it was to get around inside the pitching hull while on the surface in the North Atlantic charging batteries?

 

I think that if you back tracked back to the forward torpedo room and living quarters and did the same thing so that the observer has to look through the starboard side items in order to see the interior it would convey the close quarters even further!

 

Either way your results so far have truly been impressive! 

Edited June 15, 2019 by lmagna

[yvesvidal]

So, before showing you the finished rear torpedo compartment (I still have a few details to take care of), let's share some information about the intricacies and technical details of that section of the boat. My goal, again, is not only to show you the implementation of that great kit, but also to learn about these incredible vessels and their technical solutions.

 

The picture above shows the two electrical motors/generators used to propel the submersible, when under water. It also shows the two large electrical panels allowing the control of the motors/generators. Switching is done by maneuvering the large wheels.

 

From the "Manual": 

1)  E motors.     The E motors working as electric motors drive the propellers and working as a generators charge the batteries.  They are fan cooled, encapsulated, direct current, double armature, with compound windings and commutating poles.  The motor is built from two parts, casing with installed windings, which are bolted together.  There are also two armatures installed on the same shaft inside.  In the upper parts of casings are cold air inlets and warm air outlets.  Bottom parts up to the bottom edge of the shaft are water resistant and at the lowest points draining cocks are provided.     Each double armature motor has 2 x 8 main poles and the same amount of commutating poles.  All poles are bolted to the inner side of the rotating yoke.  The shaft has installed two armatures and runs in two slide oil ring lubricated bearings. The bearing on the diesel engine side is built as a thrust bearing for absorption undesirable thrust.     The bearings of the E motors are cooled by sea water.  During surfaced drive the cooling system is fed by the diesel engine cooling pump and while submerged, by the cooling pump.     A fan blower is attached to the casing.  It draws fresh air from the E motor room and blows from above into the both parts of the motor.     The warm air escapes through outlets in the upper parts of bearing casings and is directed to air coolers, which are installed between the E motors.

3)  Main switchboards.

b) Main switchboards with Rotary Switches     Type VIIC U-boats are equipped with main switchboards with rotary switches provided by A.E.G. Company, Berlin.     The stb. main switchboard is connected through the aft battery automatic circuit breaker to the aft battery, the port main battery switchboard is connected through the forward battery automatic circuit breaker to the forward battery.  Each battery automatic circuit breaker has following settings:                     overload current of 6000 A in 10 seconds                     short circuit current of 12000 A     The main switchboards are built from iron framework, which supports switches, control and measurement equipment necessary for driving and charging.  The order of the switches on each switchboard from left to right for both E motors is as follows:

1 Main battery switch with charging connection below 1 Starting relay with with indicator lamp 1 Field switch 2 1 Drive direction switch 1 Field switch 1 with indicator lamp 1 Motor - series-parallel - switch 1 Battery - parallel-serial - switch     Above the switches are installed the fan blower motor switch, board illumination switch, silent running drive switch, and measurement devices.     The speed controller is installed on the right side of each switchboard.  Timed relay and auxiliary relay are installed below the measurement devices and above the drive direction switch.     Main battery switch  is two-pole.  When switched on, the battery automatic circuit breaker is connected with main switchboard.  The switch is operated by an isolated handwheel.  By rotating the handwheel to the right, the switch turns on, rotating to the left turns the switch off.  In the bottom part are charging terminals, accessible through flap on the casing.           Drive direction switch is five-pole and is used to toggle the current direction in the armatures to change motors direction of rotation.  By turning the handwheel to the right, the motor runs forward, by turning to the left, the motor runs backward.  The switch is turned off when the handwheel is the middle position.  The drive direction switch is interlocked with the motor field switch so that the E motor cannot be turned on, when the field switch is turned off.           Motor - series-parallel - switch  is a four-pole toggle switch.  Turning the handwheel to the right, causes the armatures to be connected in series and the equalizer line is disconnected.  When the handwheel is turned to the left, the armatures are connected in parallel and the equalizer line is connected.  By means of auxiliary contacts the circuits of the timed relay and silent running drive switch are closed.

Battery - parallel-serial - switch is a double three-pole toggle switch.  Turning the handwheel to the right, causes parallel connection of the batteries. When the handwheel is turned to the left, the batteries are connected in series.  By means of auxiliary contacts the circuits of the timed relay and silent running drive switch are closed.           Starting relay is a two-pole circuit breaker.  It normally works fully automatically, but in case of damage, it also can be manually operated.  This contactor limits too high starting current.  Immediately after turning on all switches or after expiration of the adjustable (to 1 second) timeout the contactor opens and in its off-state connects the starting resistor into the E motor armatures circuit.  When the contactor contacts close (the current has gone down, the voltage is low), the starting resistor is short-circuited.  When the main current circuit opens, i.e. by turning off any of maneuver switches, the starting relay is opened and the starting resistor is connected.     When the relay is damaged, the starting resistor can be short-circuited manually.  In that case before setting the maneuver switches, the starting relay must be turned off. When starting relay is activated, the indicator lamp lights up.     Using the motor - series-parallel - switch and battery - parallel-serial - switch three drive speed ranges corresponding three voltage ranges can be set (see E-Sketchbook).           1. Batteries in parallel, armatures in series 2. Batteries in parallel, armatures in parallel 3. Batteries in series, armatures in parallel     Within these three ranges, further adjustments can be done by changing the current in shunt windings using the double motor field rheostat – the speed controller.  It also can be used to control the output voltage of the E motor while charging the battery. Each single rheostat is connected in series with single shunt winding of the double-armature machine, then they are connected in parallel with each other.

 

This rather complicated description gives us a feel for what it took to operate these complex machines. Needless to say, the importance of capable mechanics was paramount on these vessels, as everything was done by hand and following a very precise procedure.

 

This drawing shows the cooling system used to keep the electric motors/generators at operating temperatures. As indicated in the Manual, the primary cooling pump is located in the Diesel/engine room (bottom right on the drawing) and distributes cold salted water to the Starboard compressor and the two electric propulsion motors and fans. Definitely a plumber's dream.... or nightmare.

 

The rear compartment similar to the front torpedo compartment, is equipped with a torpedo storage between the pressure hull and the outer casing: 

These two pressure proof containers are marked in red on the drawing.

 

Internally, the rear bulkhead near the torpedo tube is equipped with an electric compressor on the port side and a diesel compressor made by Junkers, on the starboard side. These compressors are resting on top of the torpedo compensation tanks: 

The picture above shows the U-995 (only surviving Type-VIIc) which has been heavily modified and is not really representative of what an early Type VIIc was, during the war. Most likely, dual electric compressors were the norm before the Germans realized that due to extreme electrical consumption, they had to swap one of them with a diesel powered Junkers unit. The Trumpeter kit (with its short-cuts) just ignores that part of the compartment and does not offer any starboard compensation tank and no Junkers compressor.

 

Yves

Edited June 18, 2019 by yvesvidal

[yvesvidal]

Some pictures of the rear compartment. First, I had to take care of the stringer located in the rear. Because of the support I installed with the brass deck and cutout plastic deck, the stringer did not fit. The part provided by Trumpeter is not prototypical no matter what, and thus it does not make too much of an impact to modify it. It is invisible anyway: 

The picture shows the original part. Because of the realistic pressure hull end, it has to be modified to follow the convex shape. The original submersible had four stringers on the stern, as shown in the following pictures: 

Finally, some shots of the almost finished rear compartment. It is by far the most complicated to assemble, with the propeller shafts, rudder commands and the extremely tight fit of that compartment in the stern. 

I still have to glue the torpedo outside door and install a rod for the control.

I hope you like it. 

 

Yves

 

 

 

Edited June 19, 2019 by yvesvidal

[amateur]

I sure do!

(and the 'spare parts' add to the overall impression!)

jan

Edited June 20, 2019 by amateur

[torro]

so realistic

[thibaultron]

While a Type IX, for those Kindle readers the following book might be of interest. It is about the capture of U-505 by the US Navy in WWII. The book is written by the Task Force commander who lead the capture. Amazon has a free kindle edition.

Twenty Million Tons Under the Sea: The Daring Capture of the U-505

 

Amazo