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wefalck

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About wefalck

  • Birthday 05/01/1956

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    http://www.maritima-et-mechanika.org

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    Male
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    Paris, France
  • Interests
    19th shipbuilding and naval history, indigeneous boats and their history

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  1. Well, it depends what you are doing with them on a ship model ... Actually, I think there are four different topics here: 1) how to convert a 2D-paper drawing into a CAD-drawing 2) how to loft such drawings into a self-consistent data-set that produces a fair hull, and 3) how to convert the resulting CAD-drawing into instructions for the laser-cutter that produce the expected results. 4) is the laser-cutter available suitable for the task in hand As Chuck suggested, it may save a lot of time, effort and money to verify point 4 first. If the available laser-cutter is not suitable, it may be simpler to work the traditional way. On the other hand, as the envisaged model is planned to be only a foot and a half long, one may get away with quite thin (ply)wood or even cardstock. The bulkheads are only needed to define the shape of the hull, if the spaces in between are filled with a softer wood, e.g. balsa. The bulkhead do not need to be structural parts. One has to adapt the building technique to the available tools, in this case the laser-cutter. Some people work from sets of copies of original builders' plans, but it may be worthwhile going through steps (1) and (2) in any case, as this allows you to verify the fairing of the hull before one cuts anything. Even going only through step (1) is useful: if it turns out that a bulkhead is wrong, one can easily correct it in the 2D-CAD and print it out again.
  2. Well, it seems that Gruson in Magdeburg specialised in 'Hartguß' for armour and armour-penetrating projectiles: https://de.wikipedia.org/wiki/Grusonwerk. I would need to bring myself up to speed as to the metallurgy of the various types of 'Hartguß' developed for armour and amunition by Krupp, Gruson and others. Both the metallurgy and the processing determine the their properties for different applications. My area of interest in general is before 1890, so I am not so familiar with the later materials. To my knowledge HSS-tools were the only ones available to turn/mill steel during WW1. Carbide (WiDia) tools were only invented in 1926. So pre-forming shells by drawing and drop-forging saved a lot of difficult machining and, as noted before, aligns the grain in the material favourably. I gather the classification of artillery into guns, howitzers and mortars became a bit fluffy in the course of WW1, as certain howitzers were given a maximum elevation more like that of mortars. They became effectively longer-range mortars. Or, one could say that mortars were made longer in order to give the projectiles a greater V0.
  3. I didn't actually say that the shells as such were cast. I was referring to a special steel-alloy developped from the 1870s or so on by Krupp, which in German was called 'Hartguß'. Say in the 1880s, the shells, to my knowledge, actually were cast into cockilles, where the quick cooling surface hardened them. Howitzers like the one we are talking about were designed to destroy bunkers and other hardened facilities, so the shells need to be hard and tough. Too soft and they will use much of their kinetic energy for deformation and the energy will be distributed over a too wide cross-section - too hard and they will fragment on impact, again dispersing the energy. At that time, turning hardened steel was difficult to machine, so they wouldn't turn and bore shells from solid bar-stock. Rather, a process of drawing and drop-forging was used to give most of the shape. Drawing and forging also arranges the structure within the steel, to make it tougher. The square billets from which the process started in the film were presumably cast. Not sure, whether continuous casting and hot cutting would have been available at that time. At 16'10" in the film one can see that even late in the war (I gather the film is 1917/18ish) the shells were painted and were given painted/stencilled marks as to their type. Otherwise they may rust quickly, even if greased for the transport to the front. Firing a rusty shell would not be good for the gun and may difficult to load. Interestingly, our peace-time stocks and production capacities are just not capable of keeping up with war-time demands, as the war in Ukraine shows again. These large artillery barrels had only a limited life-time, after a certain number of shots they would be worn out. Peace-time shell supply presumably was calculated on this basis.
  4. @Jack12477, the young gentlemen seated to the right is wearing 'knickerbockers' or 'plus-fours' - this was the hip outdoor sports attire from the late 19th century to around the 1930s. They were used when cycling (no chain-guards, so that the trousers don't get caught), golfing (to prevent trousers getting dirty), hunting (same reason), etc. While not acceptable at formal occassion (unlike today), they were worn to show that you were a sporty person (very much like today people are wearing those horrible track-suits and the likes, even when they are not pursuing any sports). As to the colour and appearance of the projectiles: they would have been special 'hard-cast' steel, so when bare, a metallic grey. There would be also two or three guidance rings that are pressed into the rifling, probably copper or perhaps brass. The detonator (which in this case may be in the bottom of the shell) would be brass. I don't know what the WW1 practice at that time in Germany was, but normally shells would be colour-coded according to the type. I would assume that they were painted 'field-grey' or something like that to prevent rusting, perhaps with coloured bands or lettering to indicate the type. You would need to verify this against the literature.
  5. I think this has been discussed before, watch out for key phrases, such as 'digitising plans'. In general you can import an image of the body plan into your CAD system and then retrace the frames. Once this is done, you have to complete each frame station with the contours of what you actually want to cut. I gather so are aiming for a so-called POB (plank-on-bulkhead) construction. So you need to draw the respective lines for cutting out. There is a lot more detail that has to go in than can be described in such a short post. You should look at the various contributions in this section here to get an idea. Once you have the basic hull representation in the CAD system, you have to turn this into the files needed for laser-cutting, i.e. arranging the pieces to be cut to fit the machine, efficiently use the wood etc. This file has to be saved in a format that is readable by the laser-cutting software. I gather there is also information on that in this section of the forum. Not sure that basswood is a good choice, I think plywood would be better.
  6. In general, when the bowsprit is next to the stem, rather than on top of it, you are likely looking at a running bowsprit. For obvious reasons, in this configuration there is no gammoning, but either an opening in the bulwark or an iron ring to hold the bowsprit down. Gammoning seems to be also associated mainly with galion-style bows. As one can see from the first two illustrations above, a closed bow would requires some akward arrangements for the gammoning as the stemhead is too narrow. When closed bows came into fashion around the middle of the 19th century the gammoning was replaced by wooden clamps or iron straps.
  7. Looking good, the work! Somehow I thought that the exhaust pipe(s) from the safety-valves are connect to those steam-relief pipes that are attached to ships' smoke-stacks. Unlike for railway- or traction-engines and the like, you cannot just let the steam off into the the (usually enclosed) engine-room. Do you have drawings of the prototype arrangements?
  8. No update for the past three weeks - I hope everything is ok over there ... we seem to get rather mixed messages from that region.
  9. I haven't build anything with decals since about 1980*, I think. Decal technology must have advanced considerably since then. If I understand the process correctly, then you can apply the 'softener' to already set decals in order to coerce them around obstacles? I am asking this question, because I just had the idea of laser-printing flags onto decal-sheet and then apply the decals on both sides to a piece of aluminium foil cut to the right size. With this softening and drying technique, the aluminium foil with the decals on could be 'draped' realistically. Does this sound feasible? *apart from the white boot-topping above the waterline that I put onto my current project, for which I used thin strips of white decal-sheet.
  10. Thanks, gentlemen. I have not intention to leave this World in the next few months, so this is not going to be a 'project for life' 😉.
  11. Thanks, in the meantime, when I did some searches on Fowler B6 it popped up there ... 100 € for a kit is quite a steep price actually (for me, as I am not used to buy kits, but only tools and books). How long is the model by the way ? I didn't look up the measures of the original.
  12. OK, we are in serious thread-drift now ... the phenomenon we are discussing is called 'planned obsolescence'. It's something industry has been using for decades to keep up their sales. Perfectly useable hardware is made unserviceable by designing electronic components too flimsy so that they fail prematurely, well before the actual hardware is worn out. Or making software on purpose not backward compatible anymore, claiming that otherwise performance cannot be improved (even if objectively no improvement may be needed). The component concerned are often trivial, such as capacitors, but one has to replace the whole electronics and replacements are either not sold or made uneconomically expensive. In fact, the European Commission has been working for some years now on legislation to curb such practices, because they are wasteful of mineral resources and energy. I gather, as long as our economic philosophy is built on 'growth', it is difficult to combat such practices. Another dimension of the problem is, that industry faced with this 'threat' is switching to renting out 'services', rather than selling goods. To some degree this is also supported by environmentalists, as they claim that there is too much 'unused stock' in our society. Gone are the days (well into the 1990s) that Apple prided themselves that all their operating systems were backward compatible with existing software (their own). You could run ten-year old versions of wordprocessors on the latest version of the operating system. But even back in the 1990s already there were complaints that 'productivity' software had too many bells and whistles that very few people actually use in practice. Perhaps I am not such a sophisticated user, but there are very few functions that I constantly use in my wordprocessor, spreadsheet or drawing programs that were not available already 30 years ago ...
  13. P.S. Where did you get the kit from? I could not find a source on the Internet ... BTW, this is a comprehensive history of the John Fowler works: LANE, M.R. (1980): The Story of the Steam Plough Works. Fowlers of Leeds.- 410 p., London (Northgate Publishing Co. Ltd.).
  14. I am a great fan of Fowler traction engines, because of their looks and perhaps also because of their German connection: a young German engineer in search for better opportunities than on the continent ended up with Fowler in the 1860s. He made some important inventions/improvements to their ploughing engines, reorganised the Egyptian cotton industry with the help of Fowler engines and eventually became their agent for the German states and Eastern Europe with a seat in Magdeburg. Some 35 years ago, I built a Fowler Z7-type ploughing engine from a 1:76 Keil-Kraft kit (which at that time were readily available in model shops) with a lot of 'scratch'-building, as I had just acquired a watchmakers' lathe. The actual engine was virtually absent from the kit and various other aspects of the kit had to be corrected: Before painting showing the amount of detail added to the Keil-Kraft kit. Finished and painted Fowler class Z7 ploughing engine in 1:76 scale. I was lucky to live in the UK at the time, so I could visit various steam-fairs to take pictures of originals and there was also a local museum that owned a class BB ploughing engine. I didn't know that there was an 1:35 scale kit of a class B6 traction engine. I always wanted to build a model of those. The kit looks good, but it is a pity that the whole engine-block has been cast in one piece. I would want to make the metal parts from real metal ... does the kit come also with wheels with rubber tyres? This is the configuration as agricultural engine. Not sure what the army would have used. The agricultural wheels would give more traction 'off-road', but are rather uncomfortable to ride on paved roads. Incidentally, the German army experimented with traction engines as artillery tractors in the 1870/71 Franco-German War. I believe they were Fowler engines. There are not many accounts of their performance in the published literature - military writers of the time mostly were no techno-freaks and quite conservative. While their pulling capacity was judged favourably, the logistics of supplying them with fuel and water became too difficult as they moved away from railway lines. One should read up how the British did this during the Boer Wars, where armoured traction engines were used. Looking forward to the progress in this building log 😃
  15. Sounds (almost) familiar. My iPod is of 2006 or thereabouts. It was jumping tracks (I thought). So when I (unfortunately) dropped my trusted iPhone SE onto a tiled floor and the screen cracked, I decided to get an iPhone 14 pro - because of the telephoto lens and got one with 256 GB. With the old SE I had the same problem, that there was not enough memory to update the OS - but you can hook it up to the MacBook as virtual memory to go around the problem. Anyway, I managed to push across all the music including most of my CDs onto the iPhone 14, so that I now don't need to carry two devices. The same CDs still jump tracks, but this must be a problem when uploading them into iTunes. So it wasn't a problem with the hardrive of the iPod. Must do this again ... My wife tells me that I am IT-challenged, but I am simply not running after the latest things, if there is no need. Well, things have changed a bit since the days, when I did (scientific) coding on VAXes and the likes ..., but coding is still the basics.
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