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

[Blue Pilot]

Those engines are huge!  

[yvesvidal]

A few pictures of the engine. It is almost finished and I have waived the oily look.... I was ready to use real dirty oil (from my car) but decided otherwise: 

I still have to paint the exhaust and assemble it.

Yves

[jgodsey]

Spectacular!

Jim

[Dziadeczek]

Wow! It looks like someone might jump start it in a sec or two!  

[Katuna]

Haha, sorry about that! Too good not to post. One thing I really took away from the pics was the shape of the oil "pan" on the bottom. Granted, you would never see it on the Port side so I don't fault Trumpeter on that one. However, it's very apparent on the Stbd side.

 

I see you added the valve handles on the top of the engine. Those are missing from the kit, correct? It's been a while since I've even looked that direction. 

 

I was really intrigued by the way that SkipperTed weathered his engine using the Abteilung 502 Engine Grime oil paint. Really looked convincing.

[yvesvidal]

Well, the engine has been installed in its cradle, similar to what these mechanics were doing on these historic pictures. I have tried to shorten the stand of some of the rockers, to give the overall engine a more realistic look. If all the rockers were in the same position (as implied by the Trumpeter kit), then the engine would have a hard time running. It is not perfect, but at least it is better than what the kit is proposing. Also, I have added the six hand valves on top of the engine. Again, these are present in the PE sheet, but the instructions are not mentioning them.

I added a small washer between the shaft and the bulkhead, to make it look more convincing: 

Still trying to focus my poor camera on these gauges: 

And finally, giving the engine some offset, like the prototype:. The rear of the engines are closer to each other than the front (shaft/output) side.

Now, to work on the ceiling and on the other engine. 

 

Katuna, I am still debating about that oily look... It is very tempting but also difficult to represent in a realistic way.

 

Yves

 

Edited December 9, 2019 by yvesvidal

[Jim Rogers]

Beautiful work.

 

[Katuna]

yves - Maybe you're seen this before but SkipperTed did a great job using the Abteilung 502 Engine Grease. It's so hard to get a convincing damp, oily machinery look but I think this method really gets it. It's an oil so it's hands off for a week while it dries but you can go back and manipulate it for a couple days after you lay it down.

 

 

 

[Katuna]

I case you want to get a little more specific on the output shaft bulkhead flange, here's a pic from a German modeler on a different kit but in the same scale. 

[el cid]

If nothing else, you might consider doing a “wash” to help make the engine details pop,

 

I’m really enjoying your build.

 

Cheers,

 

Keith

[Tigerdvr]

If you use real used oil you will have a new height in realism--smell, odor like only an engine room can have.🛠️

Then the bolt counters will be able to discuss weather it smells correct⚔️

A really marvelously detailed engine.

 

Cheers, Harley

[Katuna]

"Then the bolt counters will be able to discuss weather it smells correct⚔️" Haha, I wouldn't doubt it! There's always someone living in their mothers basement that know better than anyone else.

[Katuna]

For the ultimate in prototypical perfection you could hop on a plane to Laboe, visit U-995 and ask to crawl around under the deck plates in the engine room. I'm sure you could come up with a few tablespoons worth of old oil. Top that one, rivet counters!

[yvesvidal]

5 hours ago, Katuna said:

Katuna, I think I know which modeler you are referring to. This is gorgeous but if it is the Hachette kit, they only have two compartments to build....not the entire vessel. Besides, once inserted in the hull, you cannot see any of these incredible details. Finally, I do not have the patience for this level of details, nor would I know where to find the information. But thank you for the picture....it is quite incredible.

 

Yves

Edited December 7, 2019 by yvesvidal

[el cid]

5 hours ago, tigerdvr said:

If you use real used oil you will have a new height in realism--smell, odor like only an engine room can have.🛠️

Then the bolt counters will be able to discuss weather it smells correct⚔️

A really marvelously detailed engine.

 

Cheers, Harley

To me the engineering spaces always smelled like diesel fuel, hot lube oil, and ozone.  

 

Cheers

[Katuna]

Yes, it's the Hachette kit by David. Mind blowing detail but as you said, it's only the engine room. I only posted the pic for the shaft bulkhead flange since the Stbd side will be highly visible. You'll barely be able to see the Port side.

 

[Katuna]

Here's a couple of the clutch arm mechanism. You know, just to heap a little more pressure on you ; ) I think I have some more info on the AMP under the U-Historia thread.

[cog]

On 12/7/2019 at 3:52 PM, yvesvidal said:

Katuna, I am still debating about that oily look... It is very tempting but also difficult to represent in a realistic way.

 

Maybe this will help

[yvesvidal]

The starboard engine is more or less completed: 

Each cylinder of the engine has a bore of 400 mm which is about 8 mm at the 1/48 scale. I happen to have aluminum tubes of that exact size, for their inner diameters. I have decided to represent the engine during its construction or rather during extensive repairs. The long threaded rods to hold the head and block around the sleeved cylinders, are made of brass rod. I did not have a 1 mm die (smallest I have is 2 mm), otherwise I would have tapped the extremities of each rod. I hope it does not look too bad....from a distance.

At this point, the second engine can be placed on its cradle: 

This makes for a cramped compartment, as is the prototype. It also allows a nice view on the Port engine with all its finished details.

Some funny views....

Soon, we will be closing the lid (installing the ceiling) on these engines.

 

Yves

 

 

 

 

[Katuna]

That came out really cool. I'm jealous! To the best of my knowledge, the pistons were paired so that two "fired" at the same time. They were 120 deg apart. I'll go check but I think 1-6, 2-5 and 3-4 were paired. Just in case you were dropping pistons in.

[yvesvidal]

Katuna,

 

I am not planning to drop any pistons, but you are right about the pairing. That is exactly how they worked.

Also, Pistons have a little crown on top, made of 4 segments. 

 

Enough insanity for me.... 😉

 

Yves

Edited December 10, 2019 by yvesvidal

[yvesvidal]

So, the U-552 was built in the shipyard of  Blohm und Voss, in Hamburg on September 25, 1939. U-552 was part of a sub-series of eight vessels, ranging from 551 to 558.

These units were equipped, apparently, with the volumetric compressor driven by gears (not turbo-charged also known as Buchi  Super-charged) and as such, used the G.W engines made by Krupp.

 

Here is what the Type VIIc Manual tells us: 

 

G.W. diesel engine installation.     Diesel engine installation of some Type VII C boats consists of 2 G.W.-engines with associated auxiliary machinery.  The engines are single-acting four-cycle with fuel spray injection and supercharging.  Both engines are reversible.

a) G.W. general and performance figures.     Type Germaniawerft Marine diesel engine, Model e.v. 40/46 with forced induction by Roots type blower Power Full load           1400 SHP   Overload          1500 SHP   Maximum load  1600 SHP Speed 470/480/490 RPM Fuel oil consumption 254 kg/hour (full load) Cylinders 6 Cylinder diameter 400 mm Stroke 460 mm Displacement 6 x 57.8 liters Overall length 5600 mm Overall height 2895 mm Overall width 1525 mm         b) Construction of the GW propulsion plant.     Bed plate and engine block (lower part) are constructed as one welded block, which consists of single, vertically standing cast steel frames, which are held down by welded steel plate.  The two cylinder blocks (three cylinders each) are connected with this bed plate by means of tie rods passing through flanges on the lower edge of the cylinders.  These tie rods relieve the working cylinders of the combustion gas forces and transfer them to the upper part of the raised bed plate.  The cylinder heads are pressed by studs on the working cylinders and thus form the upper abutment for the cylinder cans.  The fuel oil is injected into each cylinder by a fuel oil injection pump (Bosch design) and a fuel oil injector (type G.W.) into the combustion chamber.  Oil from a fuel oil feed pump (gear pump) is transmitted to the individual fuel oil injection pumps.  The delivery rate of the fuel oil pumps is controlled by shifting the regulator linkage (changing volume by means of beveled edge).  The control regulator linkage can be moved by governor as well as by fuel oil control lever at the operating station.    The governor is

built as a centrifugal governor and is driven by an idler gear from the camshaft drive.  Charging (increase in the amount of air to burn) takes place via a Roots type supercharger (G.W. type).  The charger is arranged on the clutch side of the engine and is driven from the crankshaft by means of gear wheels through a hydraulic clutch.  This hydraulic clutch and interlocking mechanism allows the charger to be used only while driving forward and engaging and disengaging it only when the engine is running.  Cylinder barrels, cylinder heads, exhaust valves and exhaust manifolds are cooled by sea water, which is fed by a coupled cooling water pump (piston pump).     The coupled lubricating oil pumps (gear pump) feed lubricating oil that is used to operate the hydraulic governor as well as for lubrication of the crankshaft bearings, cylinder barrels, camshaft bearings, the fuel oil pump control linkage and drive as well as for supercharger blowers.  The engine can be reversed either by means of compressed air or by means of a special hand oil pump.  Altering the direction is controlled by shifting the cam shaft in the longitudinal direction, so that the cams for the opposite direction of rotation engage push-rod rolls.         c) Auxiliary machinery associated with G.W. engines.   1. Superchargers.     In order to have a greater air supply available, a Roots type blower is mounted on the clutch side of the engine.  The blower is powered from the crankshaft of the engine by means of gear wheels.  The blower is driven by means of a wrap-spring coupling, which prevents torsion vibrations and which takes up the distortion of the rotating motion.  The supercharger clutch is a double cone type which can be engaged and disengaged from the operation station only while in "Ahead" drive, and only when the engine is running at full operational speed.  In order to preserve the friction lining, the operating speed is to be lowered if possible when engaging to on.

2. Pumps.           Cooling water pump.     The cooling water for cooling the engine oil cooler, cylinder barrels, cylinder heads and the exhaust is fed by a double piston pump, which is at the front of the engine.  The drive takes place via a crank, which is driven by gear wheel transmission from the crankshaft of the engine.  A safety valve on the discharge side of the pump should respond when outlet valves are closed.           Lubricating oil pump.     The entire engine as well as all important contact surfaces are lubricated by oil fed from lubricating oil pressure line under appropriate, reduced pressure.  The lubricating oil pump is driven by the gear wheel of the cooling water pump drive.  It is a gear pump and operates in both directions of rotation.  The adjustment of oil pressure takes place via a pressure control valve from the operating station.           Fuel oil feed pump.     The fuel oil is supplied by a special feed pump from the gravity fuel oil tank to the fuel oil injection pumps.  It is a gear pump and is suitable for both directions of rotation.  It is arranged over the camshaft.           Auxiliary cooling water pump.     For the cooling of the engines in case of failure the coupled cooling water pump an electrically driven centrifugal pump is provided in the diesel engine room as an auxiliary cooling water pump.  The pump performance is 48 m³/hour of water against 30 meters H2O.  The pump housing is directly connected with the associated driving motor.           Hand cooling water pump.     The hand operated water pump is designed as a double-acting piston pump.  It draws sea water and discharges it to the cooling water control manifold.

Auxiliary lubricating oil pump.     The auxiliary lubricating oil pump serves for the lubricating of the engines in case of failure of the coupled lubricating oil pumps and before start-up.  The pump is an electrically driven vertically arranged screw pump and supplies 38 m³/hour of oil with discharge head of 50 meters H2O and suction head of 5 meters H2O.  The auxiliary lubricating oil pump can be also be used for the distribution of fuel oil.           Hand lubricating oil pump.     The hand lubricating oil pump is used to transfer lubricating oil from supply tanks to the collective tanks, and in case of failure of the auxiliary lubricating oil pump to pump oil before the start-up of the engines.  It is designed as double acting piston pump and its performance is 4.2 m³/hour.         3) Governor, filter, lubricating oil cooler, starting air tanks, lubricating oil purifying system.           Governor.     A centrifugal regulator is used as a governor which is mounted on the clutch side of the engine and is driven by an idler gear from the cam shaft drive.  The governor prevents exceeding the maximum permissible engine speed by more than 10 percent.  If the maximum permissible engine speed is exceeded, the governor pushes control linkage towards the zero position.     As soon as the number of revolutions decreases, the governor returns to its previous position and the control linkage brings the fuel oil lever back to the operational position by means of a spring.           Fuel oil and lubricating oil filter.     The purifying of the fuel oil is done by means of a system of EC-edge disk filters.  To protect these filters against coarse impurities in the fuel oil

a coarse sieve is inserted in the line before the fuel oil gravity tank.     For purifying lubricating oil an EC-edge disk filter is used for each engine.  The bearing lubricating oil as well as oil for the clutches and the hydraulic governor is filtered by these filters after branching from the oil cooler.           Lubricating oil cooler.     The entire lubricating oil cycling installation is cooled by a lubricating oil cooler attached to each engine.  The cooling effect is achieved by forcing oil through coils, around which sea water flows.  The cooling water installation is so designed that oil cooler can be bypassed as a whole or partially.           Starting air tanks.     Starting and reversing the engines is done by means of compressed air at 30 at.  The compressed air is stored in dedicated tanks of capacity 200 liters each, connected together to the high pressure distributor (high pressure air bank 1 – high pressure manifold) through the reduction valve.   The pressure reducing valve works automatically and holds the pressure in the starting air cylinders at 30 at. The tanks have safety valves set at 30 atmospheres at as well as necessary connecting valves, drain valves and control valve with pressure gauge.           Lubricating oil purifying system.     An electrically driven purifier with a capacity of 250 liters/hour is provided in the diesel engine room for purifying dirty lubricating oil.  The purifier is equipped with an electrical oil pre-heater and a hot water pre-heater.  Directly coupled with the drive shaft are the pure oil and dirty oil feed pumps.  These two geared pumps arranged one after the other.  The attached dirty oil pump sucks the contaminated oil from the lubricating oil collecting tanks and passes it over the oil pre-heater into the lubricating oil purifier.  The cleaned oil is then pumped by the pure oil pump.

	The waste water from the oil purifying process drains into the bilge.  A hot water pre-heater is provided for better cleaning of engine lubricating oil.           1-1 Comparison between engines M.A.N. - G.W.
	M.A.N. Krupp (G.W.) Number of cylinders 6 6 Piston displacement 57.8. liters 57.8 liters Piston speed 7.2 meters/second 7.2 meters/second Efficiency 82.5 81.0 Speed 470 RPM 470 RPM Supercharger speed 10,900 RPM 10,900 RPM Performance 1400 SHP 1400 SHP Stroke 460 mm 460 mm Cylinder diameter 400 mm 400 mm Length (whole engine) 5630 mm 5600 mm Width (whole engine) 1400 mm 1400 mm Height 2810 mm 2895 mm Engine weight 38.476 tons 43.440 tons Weight to power ratio 13.75 kg/SHP 15.5 kg/SHP Fuel oil consumption (+) 0.165 kg/SHP 0.182 kg/SHP Supercharger Buchi Exhaust gas turbine B.B.C. Roots type charger G.W. Fuel oil regulation Over flow adjustment Chamber volume by means of beveled edge adjustment

 

 

Yves

[yvesvidal]

To stay on the subject of the Diesel engines used in the Type VIIc vessels, it is important to note that these motors could turn in both directions.

Switching from one direction to the other did not take much time and could be done in less than 30 seconds by seasoned mechanics.

 

The reversing mechanism was cleverly designed and was controlled by a single cylinder on top of each engine: 

The control was done from the front of the engines and the following drawing provides a detailed diagram of the mechanism: 

Finally, these engines had rather fragile bearings. It was not uncommon to have to replace them during a cruise and trained mechanics could do that daunting and extremely dirty task in a few hours. The movie Das Boot depicts such intervention being done: 

Mr. Tore, the expert who navigated the U-995, recounts in his memoirs how delicate and tedious it was to replace one or multiple crankshaft bearings while navigating.

 

Yves

[popeye the sailor]

superb job on those engines........they look awesome!  

[mtaylor]

I have to say "wow!" on the engines also.  

[Don_]

I believe the GW 6 cylinder diesel engine firing order was 1, 5, 3, 6, 2, 4.... The 6 cylinder diesel engine was a joining of 2 - 3 cylinder blocks, and the 9 cylinder diesel engine was a joining of 3 - 3 cylinder blocks.  On the Type VII U-Boat, the cylinder blocks were turned around to set the exhaust valves facing the interior of the Diesel room and the control links modified to facilitate this arrangement. That way they didn't need to create a mirrored image of the GW Diesel engine and this also created the counter-rotating engines and props. It was all about minimizing the spare parts situation and scarce resources.

Regards,

Don_

Edited December 14, 2019 by Don_

[yvesvidal]

We are coming soon (hopefully) to a conclusion on the Diesel engines compartment. I am now working on the front bulkhead: 

The bulkhead is cut on the starboard side, to show the various tanks, since this section will be visible from outside. And to make sure that the rear kitchen bulkhead matches that one, we cut them together: 

And then, it is the delicate assembly and endless touch-ups with paint, to make it look decent and realistic: 

A few more details, a light above the desk and we will move to the walkway assembly.

 

Yves

 

 

 

[Blue Pilot]

8 hours ago, yvesvidal said:

We are coming soon (hopefully) to a conclusion on the Diesel engines compartment. I am now working on the front bulkhead: 

The bulkhead is cut on the starboard side, to show the various tanks, since this section will be visible from outside. And to make sure that the rear kitchen bulkhead matches that one, we cut them together: 

And then, it is the delicate assembly and endless touch-ups with paint, to make it look decent and realistic: 

A few more details, a light above the desk and we will move to the walkway assembly.

 

Yves

 

 

 

Oh my gosh a few more details he says!  Incredible detail.

[mtaylor]

Such detail.  The only thing missing are the crew's fingerprints and some grease smears.

[yvesvidal]

I have been working on the exhaust system of the Port diesel engine. Most of it will be completely invisible, but I have the satisfaction to know that it is there....

 

First, the ceiling had to be slotted to allow the fixed exhaust pipe to go through. In fact, it is almost impossible to present the piping correctly, if you plan to use the hole provided by the kit. Below is a picture before: 

And after: 

The right hole will be used to insert just the elbow, from the top, and as such does not need to be slotted.

 

The exhaust is built by carefully gluing the pipe to the ramp: 

The tube is coiled with some heavy cotton thread to simulate the insulation band, that was used to insulate against the noise and heat.

 

Finally, after gluing in place the exhaust: 

Most of it is frankly invisible. So, let's enjoy it as we will never see it again, once the ceiling is installed.

 

Yves