SaparotRob
Unter Gemeine Geschwader Murmeltier XIII
Most impressive.
1:48 Engine Room #3 Battleship USS New Jersey for Permanent Display on Board. (2 Viewers)
- Thread starter Builder 2010
- Start date
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Looks great so far!
- Thread starter
- #83
Builder 2010
Staff Sergeant
After returning from a New Years Eve wedding in Miami, I got a gift from Southwest Airlines; a nice, annoying head cold. This kept me out of the shop, but not off the laptop and a lot of design work contrinued. The HP turbine is done and with accurate drawings of its foundation, I was able to draw that too. I stopped work on that because it was now esssential to finalize the main reduction gear since the MRG's fore foundation also supports the aft end of the HP turbine foundation. I continued designing the steam piping, but see a decision lurking. Too much piping will obscure the wonderful machinery that lies below. I'm also thinking that the undersides of the main piping will serve as convenient locations for LED lighting.
I was able to estimate the actual MRG gear diameters using the overall ratios, the output speed, and the relative space within the housing. I produced a spreadsheet to do the calculation. There is a slight difference in diameters between the first pinion on the HP and LP sides. The HP input rpm is 4,905 and the LP is 3,913, but the second pinions on the bull gear have to be spinning at the same speed to create the 202 rpm at the properller shaft. After doing all this, I realized that viewer will not discern any difference so I made both sides the same. I'm cutting away the gear covers on both sides so the innerds can be viewed from either direction. i did a test setup in the print slicer to print the gear set (sans bull gear) as a single part facing vertically so no supports will go on ANY gear teeth. It will work.
This was a very challenging piece to draw. I was fighting all the usual SketchUp challenges coupled with the mechanics of creating parts that will assemble correctly.
The frames were equal on both sides. I drew the overall shape and then slice in half using a big rectangular brick as the cutter and insecting the faces and removing the half I didn't want. You group the good half, MOVE-COPY it directly next to it, and mirror is using the MIRROR tool. Match them up a mating corner, explode both parts and then remove the center line making them a single part with perfectly symetrical features on both sides.
Another annoying, but necessary detail with making a SU drawing 3D printable is all the faces being "normal" not reversed. I set my default colors so reveresd faces are quite obvious. When reboring some of the bearings, the inside faces come out reversed. If this was just for an illustration, it wouldn't matter a whit, but to print they must be all forward faceing. I had to go back and reverse then on facet at a time. It's very finicky, time-consuming work that must be done. Reveresed faces are seen as missing in the slicer and missing faces don't print. This screen shot was taken in the middle of the face reversing task.
I "line bored" the bearing mounts by creating a set of shafts that were used to "cut" their channels in all the support struture. Even with this cleverness, I still created problems for myself when I didn't have the frames properly aligned when I did the cutting. I have to close up all the bearing holes and redo the whole operation. I used the same setup to cut corresponding bearing in the gear covers.
Speaking of gear covers. While seemingly uncomplicated, they took a lot of hours to get resonsable. I was shaping them without paying enough attention to my pictures. Like the gears, I don't have technical drawings of these highly-visible parts. When you come down the ladder into the engine room, the first thing you see is the top of the MRG. I tried to fix my errors, but gave up and redrew the part from scratch. Since the same on both sides—although one side has the electrical turning gear attached—Made one, copied it and then mirrored it using a -1.00 scale factor.
When I first drew the gear covers I had the lid face curved on all sides. After closer look at the pictures, it was only curved on the front and back edges, not the sides. Making the curved edges is EASY. I have an SU Plugin, Fredo6Corner, where you dial in the amount of edge to be curved, select the edges and click. Voila! Curved edges. But… to fix curved edges, or in this case, remove some of them and re-square the edges, it's a complete pain-in-the-derriere. It's not hard to erase the curve, but it's very finicky, re-laying the lines to create the square edge. You make heavy using of SU's "inference" facility that highlights the line end that corresponds to an adjacent/nearby edge. You draw out one segment at a time to the inference point of the bottom line, and then connect these lines to make faces, and finally close the long wall. It's complicated to write about it and complicated to pull it off. This shows the lines pulled out to the correct distances waiting to be connected to the same form on the other end of the part.
Today I spent time building the output end of the MRG. I didn't have a drawing of this, but a good photo I took. So the upper works are complete. I still have work to do on the MRG lower foundation and lubeoil tank upon which it all sits. The cutaway area is what's going to be printed.
The X-ray view shows the bull gear and why the housing so darn big. The bull gear is about 13' in diameter. The real one could be bigger or smaller. I don't have any information about it, but this size fits the housing appropriately, and I do have housing drawings.
So here's some eye candy to brighten up a cold winter day (for us Northern Hemisphere folks). It's definitely starting to shape up. Notice that there's now machinery on the top of the main condensate pump. The big four (HP/LP turbines, MRG and Condenser) are now almost finished. I don't expect that any of the auxiliary equipment should be more difficult.
This is the high pressure side:
And the low pressure side:
I was able to estimate the actual MRG gear diameters using the overall ratios, the output speed, and the relative space within the housing. I produced a spreadsheet to do the calculation. There is a slight difference in diameters between the first pinion on the HP and LP sides. The HP input rpm is 4,905 and the LP is 3,913, but the second pinions on the bull gear have to be spinning at the same speed to create the 202 rpm at the properller shaft. After doing all this, I realized that viewer will not discern any difference so I made both sides the same. I'm cutting away the gear covers on both sides so the innerds can be viewed from either direction. i did a test setup in the print slicer to print the gear set (sans bull gear) as a single part facing vertically so no supports will go on ANY gear teeth. It will work.
This was a very challenging piece to draw. I was fighting all the usual SketchUp challenges coupled with the mechanics of creating parts that will assemble correctly.
The frames were equal on both sides. I drew the overall shape and then slice in half using a big rectangular brick as the cutter and insecting the faces and removing the half I didn't want. You group the good half, MOVE-COPY it directly next to it, and mirror is using the MIRROR tool. Match them up a mating corner, explode both parts and then remove the center line making them a single part with perfectly symetrical features on both sides.
Another annoying, but necessary detail with making a SU drawing 3D printable is all the faces being "normal" not reversed. I set my default colors so reveresd faces are quite obvious. When reboring some of the bearings, the inside faces come out reversed. If this was just for an illustration, it wouldn't matter a whit, but to print they must be all forward faceing. I had to go back and reverse then on facet at a time. It's very finicky, time-consuming work that must be done. Reveresed faces are seen as missing in the slicer and missing faces don't print. This screen shot was taken in the middle of the face reversing task.
I "line bored" the bearing mounts by creating a set of shafts that were used to "cut" their channels in all the support struture. Even with this cleverness, I still created problems for myself when I didn't have the frames properly aligned when I did the cutting. I have to close up all the bearing holes and redo the whole operation. I used the same setup to cut corresponding bearing in the gear covers.
Speaking of gear covers. While seemingly uncomplicated, they took a lot of hours to get resonsable. I was shaping them without paying enough attention to my pictures. Like the gears, I don't have technical drawings of these highly-visible parts. When you come down the ladder into the engine room, the first thing you see is the top of the MRG. I tried to fix my errors, but gave up and redrew the part from scratch. Since the same on both sides—although one side has the electrical turning gear attached—Made one, copied it and then mirrored it using a -1.00 scale factor.
When I first drew the gear covers I had the lid face curved on all sides. After closer look at the pictures, it was only curved on the front and back edges, not the sides. Making the curved edges is EASY. I have an SU Plugin, Fredo6Corner, where you dial in the amount of edge to be curved, select the edges and click. Voila! Curved edges. But… to fix curved edges, or in this case, remove some of them and re-square the edges, it's a complete pain-in-the-derriere. It's not hard to erase the curve, but it's very finicky, re-laying the lines to create the square edge. You make heavy using of SU's "inference" facility that highlights the line end that corresponds to an adjacent/nearby edge. You draw out one segment at a time to the inference point of the bottom line, and then connect these lines to make faces, and finally close the long wall. It's complicated to write about it and complicated to pull it off. This shows the lines pulled out to the correct distances waiting to be connected to the same form on the other end of the part.
Today I spent time building the output end of the MRG. I didn't have a drawing of this, but a good photo I took. So the upper works are complete. I still have work to do on the MRG lower foundation and lubeoil tank upon which it all sits. The cutaway area is what's going to be printed.
The X-ray view shows the bull gear and why the housing so darn big. The bull gear is about 13' in diameter. The real one could be bigger or smaller. I don't have any information about it, but this size fits the housing appropriately, and I do have housing drawings.
So here's some eye candy to brighten up a cold winter day (for us Northern Hemisphere folks). It's definitely starting to shape up. Notice that there's now machinery on the top of the main condensate pump. The big four (HP/LP turbines, MRG and Condenser) are now almost finished. I don't expect that any of the auxiliary equipment should be more difficult.
This is the high pressure side:
And the low pressure side:
Last edited:
Vic Balshaw
Major General
I can probably count on two hands the amount of times I have travelled and NOT ended up feeling ill and believe me I've travelled far and wide in my lifetime. On the positive side you have been able to make good progress on the project, I am impressed. 
SaparotRob
Unter Gemeine Geschwader Murmeltier XIII
With above.
