Tores mailbox VIIC and VIIC/41 operation and technical details

[tore]

Don.
As you are about to finish your Skizzenbuch I would like to mention a last item worth while to include, the clutches and the shafting system.
 In addition to the clutches described in the emergency manual operation of the hydroplanes, there are several clutches in the shafting system as well as clutches in the Roots blower of the GW engines.
The main clutches between the main engines and the E-motors/generators are double cone friction clutches pneumatic hydraulic operated and I have made some sketches and photos previously on this thread.
The double cone tail clutches, manually operated, are situated just after the E-motors/ generators and the Michel thrust bearings.
The Roots blower clutches are situated in the aft end of the main engines having  maneuvering handles extended to the maneuvering stand up front towards the pressurehull sides. The rods of same are  connected to the aspirated air inlet shut off valves and interlocks as well.
Tore 

[tore]

Don.
My description of the pneumatic/hydraulic clutch between the main engine and E-motor/generators can be seen on page 88 and 89 on this tread.
Tore

[Don Prince]

Hello Mr. Tore,


You are correct and I will add the clutches. Do you have any good photos of the back end of the Diesel engines with the clutches?  I believe the drive was both manual and hydraulic???.  I pulled a photo from u-historia and they show the e-motor clutches and levers to engage.  Was this only manual for the e-motors?


Also, there is a photo of the diesel engines from the back and there are three hand-wheels shown.  My guess is the two large ones are for manually engaging the diesel drive shaft clutches...  How do they engage the Supercharger clutches and I believe they are engages while the diesel engine is running.  I will post the photo.


Regards,
Don_

[tore]

Don.
The only pneumatic/hydraulic operated clutches were the two between the main engines and E motors/generators. As an emergency alternative they could be operated manually by the wheels shown on your photo my sketch below shows how they works. If you need further explanation just ask. The third handwheel (small) has nothing to do with the clutches and belongs to the ventilation system.
As to the clutches for the Roots blower they are operated manually from the maneuvering stand up front of the engine. However on your photo you see the casing of the clutch
just below the blowercasing. As there are interlocks and other elements in the manual operation of these clutches I shall revert to that system in a different post. You are right in your assumption that the Roots blower is connected while the diesels are running.
Tore

[tore]

Don.
The clutches for the Roots blower on the GW engines have to be interlocked for several reasons, for the direct reversible engine an interlock is needed to prevent the clutch to be engaged when the maneuvering handle is in astern position, for both reversible and nonreversible engines it is an interlock preventing the clutch to be engaged when fuel handle is in a position corresponding to, at normal load, the enginerevs are below 420 rpm. At the same time the normal aspirated inletair ducts have to be shut when the Roots blower is engaged.
All these functions are obtained via linkages from the manual clutch lever up front of the mainengines as can be seen on the drawing below. There is a slight deviation between the basic arrangement for the direct reversible and non reversible engines. The maneuvering diagram shown is a direct reversible execution. The Roots blower drive is a PTO of the camshaftdrive and having a wrap spring coupling for torsional vibration reasons and a double cone friction clutch as can be seen on the drawing. In order to save the friction lining of the clutches, you would like to engage the clutch at lowest possible revs as the inertia forces caused a heavily wear on the friction lining.
On the MAN engines these clutches were not needed as the turbocharging ( Buchi system) could operate during the whole rpm range as well as astern.
Tore

[Don Prince]

Hello Mr. Tore,


I have a question about the distribution cock for the pneumatic-hydraulic system...  Should the cock be a change-over cock with a central passage type valve?  My reason for thinking this way;


If the non active cock position provided a path to both pressure flasks so if the pneumatic-hydraulic system failed, then the hand-wheel could be used and it would move the piston via the worm shaft nut and easily move the hydraulic fluid from one side of the piston to the flask with no air compression.  There would be no back pressure???


What do you think?


Don_

[tore]

Don.
If you study the systemsketch you shall see the central passage is already there and the handle for the pneumatic/hydraulic system has three positions: In, Out and Neutral, the latter position allows the hydraulic fluids as well as the confined air to shift as there is no volumechange (external air supply) while in manual (neutral) operation position.
Tore

[Don Prince]

Hello Mr. Tore,


Thanks for the response...  Would the valve cock handle be spring loaded to return back to the neutral position connecting the channel between the two flasks?  That way if there were a failure of the Pneumatic-hydraulic system, then the manual operation would not require any distribution cock lever change?


Regards,
Don_

[tore]

Don.
The handle for the pneumatic/ hydraulic system is springloaded but only to lock the cock in the selected position, the lock is released by pushing the knob on the top of the handle. In the unlikely event of loosing the pneumatic pressure and it was vital to have the clutch engaged, I guess you could keep the clutch in position by moving the cock as indicated on my sketch however  this was not a standard position. I never tried it.
Tore

[Don Prince]

Hello Mr. Tore,


I wrote a section "Drive Propulsion Systems.pdf" and it is now in dropbox.  I quit building pages in the 3 Skizzenbuch sections because of file size.  I'm just guarding against file corruption this late in the book write-up because of MS Word problems with large files.


If at all possible would you please check the 8 pages?  And make any suggestions that you believe is needed.


Kind Regards,
Don

[tore]

Don.
I have read your 8 pages which seems to be OK apart from a couple of obvious misprints. It looks as if you have copied some old manuals as to the various diesel  operations as there are no mentioning of the alternative schnorcheloperations which you have described in your Skizzenbuch previously.
I guess a more extensive explanation of the thrust bearing would be worth while. The thrustbearing is a Michell ( pronounced Mitchell) type of bearing having thrustpads on both sides (ahead and astern) of a forged (intergrated) disc on a shaft stub which turns in ordinary slidebearings. The pads have whitemetal slidingsurfaces towards the disc and a ridge or knob on the backside able to tilt the pad, creating a wedgeshaped oilfilm between the thrustpad and the disc during rotation. The bearing has a selfcontained lubrication system with an oilsump which is watercooled either from the central cooling pipe or from the compressor coolingwater pump, see my sketch. Red is pressureline, blue is discharge. The bearing housing has a sturdy foundation secured to the pressure hullstructure (red) able to absorb the thrustforces to the submarine. Kindly note that the British version of coolingwater plate 13 is not correct on this point, the original German is OK. Aft of the bearing housing is a PTO to the propellershaft revs counter.
Tore

[Don Prince]

Hello Mr. Tore,


Thank you for the info on the thrust bearing...  I updated Skizzenbuch and the Propulsion Drive System starts at page 352...  The latest version of Skizzenbuch is in dropbox.


Regards,
Don_

[tore]

Don.
I checked your latest Skizzebuch page 352 OK. However I accidentally discovered on page 312 and 313 you have two almost identical drawings of the MAN reversing system. In your cramped space I guess only one drawing of the system is sufficient and page 312 has the best copy. On page 308 and 311 you have the same for the GW engine page 308 best.
Further you better check page 315 and 317 which has the same crossection drawing as well as page 314 and 316 which alltogether would save you some 4 pages.
Tore 

[Don Prince]

Hello Mr. Tore,


Those duplicate plates were intentional...  There are the plates with some English notation and there are the original plates with only German text.  I have done this throughout the book with the English index and the pure German indexes, and the English noted plates and the pure German plates.  It was sort of a verification of the information presented to the reader.


This duplication has definitely increased size of the book.  If the book is ever published, then perhaps the publisher may want to remove the German-English duplication.  For my own personal view this will stay for when I commit it to print my one own personal copy and place the pages into my black leather covered metal post binder.  That post binder cost me just over $245 USD and is expandable to any number of pages.


Thank you for noting the pages...


Kind regards,
Don_

[tore]

Don.
I guess your Skizzenbuch shall be some book. Be aware of that some of the translated copies of the system plates have some mistakes both with regards to the text and the sketch particularly with regard to pipelines crossing. Re: cooling waterpipes thrustbearings and cooling waterpipe spare cooling waterpump main engines.
Tore