Tores mailbox VIIC and VIIC/41 operation and technical details

[Don Prince]

Hi Vic,


I seen the error after I reviewed the reversing mechanism...  I could only partially read the 2 items left on the metal plate.


The lever to the right has 4 positions:


Stop       --  top
Operate
Reverse
Starting  --  Bottom


So the starting sequence would be:
1.  Turn the wheel to supply starting air
2.  Move the right lever to starting
3.  When sufficient rpm, move the left lever to a low fuel amount
4.  Move right lever to operate
5.  Turn off starting air
6.  Move left lever to higher rpm


Regards,
Don_

[tore]

Don.
Almost correct, but as soon as the cylinders ignite you move the starting air handle back to shut off the air to the cylinders. and then shut the starting air supply valve. The reason is that you  disengage the cylinder startingvalves from the camshaft as soon as possible shutting the valves.
Tore

[tore]

Mark.
The way the VIICs behaved in the rough sea fascinated me and the pitching gave a spectacular view. As you know the designers made some effort to reduce  the pitching by introducing the watertight bow and stern as well as on the VIIC/41s, the Atlantic bow, having a flare. The floodgates of the watertight bow and stern contributed even more to the dramatic sight of spray.
I don`t know much about the graphics but as I understand you are busy with the subject right now I have adopted one of my paintings of KNM Kaura ex U 995  (VIIC/41) to show my ideas about the spray. In the game graphic, the spray is almost absent and the sea gushing over the casingdeck drains very quickly. In real life the sea was almost constantly covering the casing deck.
The movie Das Boot gives an excellent impression of the real thing. I am not sure if it is feasible to achieve these effects in a game programme so excuse me for interfering.
Tore

[VIC20]

The mobile devices can't handle much more spray than shown in this video: https://www.youtube.com/watch?v=5PYCpmEKu5U&list=UU03RMMpKkHkZVROUHFTWYVA


Spray is transparent and everything that is transparent costs a lot of performance because screen pixels has to be drawn several times.

[tore]

Mark.
I had the feeling it was something like that
Tore

[Don Prince]

Hello Mr. Tore,


The lever to the right has 4 positions; Stop, Operate. Reverse. and Starting.  When is the Operate position used?


Regards.
Don_

[VIC20]

Tore, do you remember the color of the isolators(?) on this (colored) picture?

[tore]

Don.
The starting lever has a nameplate which is a rudiment from the direct reversible dieselengine, hence  the 4 positions. First of all, plate 29 has a wrong translation "Umsteuer"does not mean "reverse" it means shifting of the camshaft to ahead or astern position. As the direct reversible engine required a lot of complicated operations as, lifting the cylinder valve rollers up from the camshaft, moving the camshaft axially, lowering the rollers down on the camshaft, starting again etc. they combined parts of these operations in the starting handle by adding links and cams, including various interlocks,  to the startinglever movements. During these timeconsuming prosesses the handle had a position "operate". On the non reversible execution the starting lever had only two functions moving the rollers down ( start) or moving the rollers up ( run) from the camshaft, thereby distributing starting air to the cylinders (start) and shutting of same (run) soon as you achieved the proper revs.
Tore

[tore]

Mark.
It is hard to remember such details more than 60 years back. However I thougth they were dark green when I made my model, but it could be dark brown.
Tore

[Don Prince]

Hello Mr. Tore,


On Plate 29, what does the shaft Lenkerwelle do?  The stop and the operate positions have the same valve configuration; that seems redundent?  I think I was wrong on my start sequence; I believe 1st should move lever to start, and then turn on the air.  If I turn on the air first and start moving the lever down to start; I pass reverse (or lifting and reversing) and I would not want that to start???


There is a lot to think about on plate 29...


Regards,
Don_

[Don Prince]

Now, that photo I had of the engine levers where the starting lever only had two positions; Stop and Starting.  U-995's diesel engine did not have reversing...


Don_

[VIC20]

…On Plate 29, what does the shaft Lenkerwelle do?  …

A Lenker is something for steering. Sounds like it has something to do with dive planes or rudders… or maybe the governor?

[tore]

Don.
Lenkerwelle is a shaft going along the camshaft. One of the purposes is supporting the  leverarm for the cylinder startingvalve camshaft roller, the other (for direct reversible engines) having  cranks and rods connected to the HP fuelpump camshaft rollers pulling them away from the fuelcams on the camshaft when axially moving same for changing direction of rotation, see plate 30.
I don`t think your last proposal for starting is the correct one. You first open the main starting air supply valve admitting starting air to the cylinder starting valves and startingair manifold. Then you move the startinghandle to start, on a direct reversible engine you pass the "umsteuer" maneuvering position and the run position nothing happens, the run position is only the ventingvalve open the others shut. On the maneuvering position the air is only admitted to the slide for the ahead/asternhandle which remains in the position for rotation  selected by the handle.
When the starting handle is in start position  air is admitted to the top piston on the cylinder startingvalves pushing the rockerarm down and engage the rollers to the starting cams, on direct reversible engines to the cams which are selected by the ahead/ astern handle, and the engine start to run on air. When you obtain the proper revs you move the handle to "betrieb" or "run" the valves supplying air to the "umsteuer" mechanism and top of the cylinder starting valves are shut, the vent valve on the air manifold opens and the spring under the top piston on the cylinder starting valve  is forcing the piston up which lift the starting valve rollers from the camshaft.

[tore]

Don.
Yes the U 995 as well as the other of our VIICs did not have direct reversible engines. Thus I was never operating a direct reversible GW engine.
Tore

[Don Prince]

Hello Mr. Tore,


Can you please explain this sentence...


"On the maneuvering position the air is only admitted to the slide for the ahead/astern handle which remains in the position for rotation selected by the handle."

Does it mean the handle has to stay in the reverse position in order to start the reverse process?

Regards,
Don_[