HubertB

She’s got skinny legs, a fat belly, a flat nose with big nostrils … …but beauty is in the eye of the beholder, right ….🥴 ? I have reached a significant milestone in this marathon conversion : the fuselage is now closed, and the major conversion parts added. But first, some pics of the new undercarriage, with its brass rods reinforcements. After my geometry blunder, I changed the approach, and split the undercarriage design in two halves, with a front and a rear half. I could thus add the brass reinforcements rods whilst respecting the planned geometry. Brass loves CA glue, so that makes the build both easy and sturdy. Some in-progress pics : It looks good on the pics, but in fact the rear diagonal struts link to the main axle proved a bit flimsy, especially split in two halves. They did not resist the assembly process, especially as, although the cavities in the undercarriage struts were dimensioned with a margin, the mating with the other half resulted in some gaps to fill and sand. I resorted to cheat a bit with scale accuracy, by making the mating point larger in scale than it was IRL. I added some Milliput lumps which allowed to ensure a strong joint when regluing the rear struts in position. I could close the two fuselage halves, trapping the cockpit structure in- between. After this operation, I found a slight design issue with my conversion parts : when measuring the (flimsy, after cutting chunks of it) fuselage halves, i designed my parts around a 27 mm width. When they were mated together, I found that the width was in fact 28:mm . But the good thing about designing and printing your own parts is that accurizing them is a fairly easy operation. I had to re-design the under cowling with an extra mm width, and then the radiator to fit the larger nose. The lower fuselage fairing was too narrow at the rear end, also by a mm, and that was also re-designed and re-printed. And that is how it looks tonight, when assembled. The undercarriage had to be inserted before mating the new lower nose. I can confirm it is strong. Hopefully, it will remain strong when the weight of the main wing is added 🤞. The radiator is only loosely placed, as is the cockpit coaming (more on that later) and the fin - which is dutifully offset a few degrees to starboard, a point overlooked by Lukgraph, but visible on the factory drawings. The supplementary belly fuel tank is a solid chunk of printed resin, and I found that it had warped somewhat after a few weeks. This seems a more common issue with thick 3D-printed parts than one would think initially, apparently. I did not bother re-printing one : some filler and agressive scraping and sanding cured the issue, os in old-style modelling 😂. And the sharp-eyed among you will have noticed that the very thin resin of one of the undercarriage struts got partly broken off during the gluing, or sanding, process. Oh well, it is easy to repair, either by cannibalising an other strut - I have printed a few - or adding some properly shaped Milliput Now about some experimentation. I mentioned in an earlier post that I still had to design the windscreen parts. They are a fairly involved design, especially where they meet the fuselage. I ended up designing them in situ on the cockpit coaming, and decided to try to print the whole part in transparent resin. When it is coming out of the printer, clear resin is cristal clear. But the washing and curing process results in a more cloudy appearance. This is due to the printing lines, which generate a small light diffraction. However, the transparency can be restored somewhat, by buffing the part, and coating it with clear varnish. After a few trials, which involved trying different clear resins, different thickness for the print layers - 20, 30 and 50 microns - and different varnishes, as well as some buffing, I found what I think is a satisfactory solution, especially as we are looking at a 1930’s aircraft on a long-haul flight though the - dusty when landing and taking off - Sahara. I believe I can improve even more the transparency by some gentle sanding and buffing and then adding a second layer of varnish, btw. Now the masking is going to be « interesting » 🤪. Hubert PS: on the pics above, only the windscreens have been varnished. The rest will be painted, so transparency is not a requisite.

Good to read. Thanks, Tim. Hubert

Looking great Gus. And the pic setting is totally adequate for the excavator. You really get an « in the works » feeling 😂 Hbert

I am with you guys. Great NMF and also the checkerboard 👍 ! Hubert

I remember standing under the wing of a Gannet in a museum visit. I was shocked by the thickness of the wing. Talk about the aerodynamism of a barn door 🤣😂😂 Hubert

Following Rob’s advice, I played with the editing of the camel pics. Below are some pics that are more representative of the real life camel model … And the pic of the Japy pumps : And the pump in situ Hubert

With a camera, yes, Rob. But I have only my iPhone ATM. Hubert

Making some headway (at last) … the cockpit …with the Japy pump Well, after a few days wasted fighting a reluctant resin, some progress to show, at last I think I can call the cockpit finished. I resisted the AMS urge to add more details like the command cables (which were doubled on the Potez 25). A sense check with the fuselage taped together and tje cockpit coaming in place showed that there was more than enough in place for what would be visible in the end. Even the time spent trying to achieve a worn leather look to the seat cushions was not that necessary, as most is hidden by the safety harness I did add some variation to the wood finish with oils, pastels and inks. And I am happy with the aspect of the printed throttle quadrants and trim wheels. Better, IMHO at least, than the PE parts supplied by Lukgraph. The French Navy Potez 25 were liaison and servitude aircrafts, so no armament. The folded PE square on the right side of the main IP, which gives access to the machine gun breech on the fighting aircrafts, was filled-in with an additional instrument using Airscale’s bezels and instrument decals. I used the Lukgraph-supplied decals for the other instruments, but thecompasses, where I felt the decals were a bit too bland, and Airscale’s products came to the rescue again. And I added the radio sets I printed, duly painted. Anyway. On to the pics : But wait ! The Potez cutaway drawing of the « Black Cruise » Potez 25 - and my bet is that the « Pink Cruise » ones were no different in that respect - indicates clearly the presence of the Japy pump. I am sur you have all seen these pumps, used for manual transfer of a liquid from one container to another. For the Sahara flights, the Japy pump was used to fill-in the fuel tanks from the barrels. What is amazing is that Japy, a French company, still exists today, and is still producing the same hand-pumps (plus a raft of other pump devices) than a hundred years ago. So, I had no difficulty finding reference drawings with dimensions, to design a 1/32 Japy pump, and print it. I printed 5 for safety. They were - and are still - sold with a 1 meter-long plunger steel tube, and a 2 meters-long flexible tube to transfer the fluid to the tank. So I duly added them, on three of them. And the Japy pump in its place in the cockpit : Whilst I was waiting for oil paints to dry, I also prepared the fuselage halves for gluing them together. My concern throughout this build is to make it string to withstand the weight of the finished kit and its heavy one-piece main wing. I have added renforcement bulkheads where the cabane struts will be attached, and where the lower wing will be glued to the fuselage. Lukgraph has molded a recess for the lower wing, with holes for carry through spars. But this means the resin at the wing root is very thin, when it will be bearing a big chunk of the aircraft’s weight. So I added some 2 mm thick plastic card on the inside, that will insert into the cockpit frames and make the whole more solid. By the way, the French aircrafts of yhe era were painted a dark « interior green ». And I have also started painting one of the two key elements of the vignette The blue background, and the bench lighting, do not help to see the color modulations, but I am pretty happy with it TTFN Hubert

In principle, the idea of sharing 3D-files seems a good idea. However, designing a 3D part can be time consuming, even if this is a hobby and we do not see the time there in the same way as working time. Sharing a 3D-file for free means the designer looses control of the whereabouts of the said file. And who says that the file will not end up in the hands of someone who will then sell the file to others for a profit ? We already see a lot of this with music or video creations. This is basically piracy of intellectual property. There are already some websites that share - for free or for a fee - some 3D files. This was also the principle of Shapeways, who also did the printing, but finally priced themselves out of the market. I have already shared some printable 3D files, and asked the recipient that he did not re-share, or worse, resell, the file. But it’s a game of trust. Doable on one-to-one sharing basis, but making files available through a website or forum is opening Pandora’s box IMHO. Remember the rules that had to be established for the Xmas raffle ? Just another proof that people profiteering from others’ generosity do also exist in the modelling world. Hubert PS: nice progress Jeroen. Sorry abou the thread drift.

… And the first car to go above 100 kph, 125 years ago, was electric : La Jamais Contente. Hubert

Definitely for SMall pARTs Hubert

Plus, in my experience, all the paints of the Vallejo galaxy are difficult to thin. In theory, water should work, but it’s not that great. Most other thinners, but for Vallejo’s own thinner, will result in a goey mess. I really love that I can pour MRP paints directly in the airbrush cup. Plus they spray beautifully. Hubert

You're welcome PW You playing golf ? I live on a golf course, and the weather here is generally much better than in Ireland, Scotland or the UK in general. Golf is my second occupation now that I am retired. Hubert

Thank you Rob. I do not want to scare anyone away from trying 3D- printing. Truth is it can be very easy - both machine manufacturers and slicing software developers work hard for that - and you can get a success (almost) everytime, But it can also be extremely frustrating when using the same parameters results in a failure when it was a success the day before. I think you should read from all my errands that I am not as good as some said in this thread . Ruffling my feathers to send me back to the ground is not a bad thing , even if the landing may look more like a crash sometimes 😂🤣😉. Anyhow, I am now back to good printing results. FWIW, Anycubic’s « Translucent green » resin has proved to be both a high resolution and a fail-safe product, again, as I used it a few years ago for printing my Travel Air Mystery Ship. I intend to try a bit more modulation in the cockpit and follow your ideas. Right now, I shot some primer on the newly-printed cockpit-détail parts like the throttles or trim wheels. Modulation trials comes this afternoon. And I designed and printed yet more new parts for the Potez. I was wondering how Lukgraph had managed to print the wing and cabane struts hollow, in order to inset a reinforcement rod. Well, they have not. The holes are only about 8 mm deep. I managed to drill a complete hole in a 60 mm long strut, but it was tedious, frankly, and I was lucky to be able to - almost - meeting holes when I was drilling the strut from both ends. And then I realised that Lukgraph had the struts wrong anyway. They are angled outwards. Lukgraph says it should be 27 degrees. A drawing in the « Potez 25 » book shows 39 degrees, and is wrong, but checking on pics and the Potez factory drawings. I found the right angles, both from the front and from the side. And the print this night worked great, including see-through holes for the reinforcing rods. So far, I have designed and printed some 30 different parts for this project. i have still to design the pilot and passenger windscreens and print them in clear resin. More later. Hubert

She’s looking good Kevin Hunert

To be fair, the slicing softwares have a database of printers with pre-set parameters most suitable for the said printer. But some factors can influence the printing, and this is where you start playing with the parameters. In the end, I think the resin reacted badly to humidity and / or air temperatures, to loose the tensile strength that allowed the supports to resist the suction forces when lifting the plate and print. Hubert

Measure twice to print once, and then 3D printing woes ... Well, I expected far more progress than what I have been able to achieve over the last 10 days. I have started preparing the fuselage for assembly. When checking the fit of the various components, I realised that : 1) the cutout in the front corners of the main fuel tank extensionwere not enugh to ensure the fitting of the nading gear. SO back to the (virtual) drawing board. 2) but also, I had not designed properly the landing gear, with the rear diagonal struts ending some 4 mm too far forward than they should. To make matters worse, I had shortened the "wheel base" even more when I assembled the various parts of the landing gear with the reinforcing brass struts ! So, guess what, back to the drawing board again, this time with a different approach that will allow a correct geometry. Fine enough, but then I have to tell you more about 3D-printing finesses There are many variables you can adjust when 3d-printing with resin. To explain a bit more the way this works, once the slicer has produced the big file with all the thousand of slices, and you import it in the printer for printing, you can launch the printing operation. As i mentioned, the supporting plate for the printing is upside-down, lifting progressively, layer after layer. The bottom of the resin vat in which the plate is immersed has a transparent film bottom, and the "image" of the slice to be printed is projected with a UV-led through the film, triggering a photo-ploymerisation of the resin, the layer to be printed becoming solid. In the process, the printer then lifts off the plate, to break the suction from the resin on the film, and lowers the plate again, with just the new layer thickness difference. When setting a print session, you can adjust: 1) the layer thickness 2) the exposure time for the UV projection 3) the exposure time for the "bottom" layers, that will stick to the printing plate. You want to ensure a strong adhesion, that will fight the suction and tensions of the printing process 4) the rest time after exposure of one layer, i.e; .he time before the printer lifts off the plate 5) the delay after the rest time, before the actual lifting of the plate, 6) the lifting speed of the plate, for the bottom layers and the ordinary layers 7) the speed at which the plate is going down again 8 the area, shape and thickness of the "raft" which is the part that will stick to the plate, and hold all the supports for the printed part 9) the orientation of the part relative to the printing plate 10) its distance from the plate, which will determine the base length of the supports 11) the density of the supports, which is then automatically calculated. Plus you can then add more supports if you tink it is necessary 12) the shape of the contact point between the "raft" and the support, its diameter 13) the diameter of the support beam, at its "bottom", middle and tip 14) the shape and diameter of the contact point between the support and the printed part 15, the depth of the contact point "in" the printed part 17) the shape and density of cross braces between the supports, to ensure they do not bend or break as the printing process takes place, with its suction and tension forces to counter-act.... I am sure I am forgettig a few more parameters, but, if you count the multiple data in the above list, it means you have about 30 or more parameters you can adjust for the printing process ! Which means about as many reasons for a print to fail. Then there is the type of resin, its colour, its viscosity ... Then there is the cleanliness of the printing plate, its "grain' to ensure a proper adherence of the first layers ... Then there is the transparency of the film, and whether it develops its own stickiness - the isopropylic alcohol you use for cleaning can induce a stickiness to the film Then as I found out, you have outside factors like the air temperature, the relative humidity and the resin temperature that will also have an influence ... I mention this last point because the temperatures have lowered recently, and the humidity climbed like a rocket, as we got the successive storms coming from the Atlantic. So, to make a long story short, I have had 10 days of successive print failures, sometimes with 2 print runs in the day. And all of this using the same - new -resin I had used for my previous prints . The problem was that the supports failed to « hold » and seemed to delaminate and break away from the raft. All the tweakings I tried, and there are a few possibilities, as you can guess, resulted in the same miserable fails ... Yesterday, in despair, I came back to an older version of the slicer software, just in case, with the original parameters, and using a resin that is supposedly 2 years beyond its "use-by" date. And it's a 95 % success ! So, where do I stand to date ? I have started painting the cockpit structure. It was wooden, so I used oils on a sand base. The result is a bit too uniform for to my liking, but there is no way I am redoing this now, especially as the cockpit openings is larger than on some other biplanes, but not that large in the end. I have started adding reinforcements for the inside, for all the areas that will be carrying either the weight of the wing, or of the whole finished aircraft. This is when I decided that I did not like the PE parts from Lukgraph. The problem for me lies in the fact that the brass sheet is quite thin to begin with. After the etching process, you end up with too thin and too frail-looking bits, which do not resist the painting process to top it off. The solution to that ? Print some new parts like the throttle of the trim wheels (the latter wrongly placed on Lukgraph's instructions). Assming of course you can print them satisfactorily ... This what the painted cockpit looks like as of today. The front bulkhead is an add-on not yet fully painted, that, like on the real aircraft, bears the structural loads of the wings and landing gear. And a close-up on the PE parts Among the multiple fails, I had some parts that printed well, to replace the PE components. They are in dark grey or red clay colour in the pic : A lot sharper and with a more "solid" feel than the flimsy PE parts your can see on the right of the pic for comparison. But wait ! This is a French aircraft. And on French aircrafts, the throttle in the "off" position is pushed forward, not pulled backwards like on British or US planes. Who wrote "Measure (think) twice before commiting to printing ?" Some smart a#$$ I am sure . So back to the drawing bord. That's a two-minutes mod, so no big deal, but now I have to print those again. TBC Hubert

I really like the realism of your craters and stones. However, with 4 (counting the one that destroyed the bridge) very close shell impacts, I would argue that all of the church windows would be blasted away - at least the glass between the lead lattice - unless they were planked (or taped, but I do not know if this was a practice in WWII Germany) over for protection. Hubert

I think your skills are good enough for any Z-M kit, Mike, and it’ very obvious Hubert

Another shell crater would mean a lot more breaking all round. It’s good like that, with the broken bridge. The church façade should probably display some ( discreet, it’s stone after all) shrapnel impacts, though … Hubert

Agreed it makes a lot more sense now. The church windows should be blasted as well. Hubert

What an outstanding build, Peter ! I know you like NMF to show your metal work, but this one painted is just as great. What can I say besides that I have not enough superlatives to express my feelings ? So, what's next ? Hubert

Thanks a lot Kevin. I am happy to report that I have been able to assemble a reinforced landing gear. With 1.5 mm brass rod for the lower axle, 1.2 dia in the four front V braces and 1 mm in the rear diagonal struts, it is plenty strong, and nothing to compare with the resin-only first model. And it still looks the same, and scale-accurate Update pics soon. Hubert

I found this render (no idea if it is accurate or just artistic licence): https://steamcommunity.com/sharedfiles/filedetails/?l=portuguese&id=1820960444 And this illustration : https://sciencephotogallery.com/featured/northumbrian-locomotive-cci-archives.html And this picture : HTH Hubert

What John and Martin said : Hubert