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roma847

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About roma847

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  1. Hello everybody, unfortunately, there is no feedback from the two experts so far, whyever ... If I understood Vincent Morales right, that the Peak-to-Valley 5'' is the spacing from the top of the wavy pattern to the deepest point of the valley, then the Peak-to-Peak is the spacing from one peak to the next one. But somehow my 7th sense tells me that his 5'' can't be quite right, maybe it's a bit to large, or I'm misinterpreting his term Peak-to-Valley so far.  That's why I took a different approach, because ultimately for scratch-building it is crucial, how many rings were on the ET, whereby the difficulty is only to determine this number as accurately as possible, wherefore I used these two Hi-Res photos. This old photo from the initial phase of the shuttle program I wanted to evaluate anyway, because one can see this wavy ring structure on the LH2 tank quite clearly. And meanwhile I also know that this photo shows the rollout of the first LWT ET-8 for Challenger's STS-6. Source: forum.nasaspaceflight.com (Jester) However, especially in the front area at the beginning of the LH2 tank, this photo is simply too fuzzy for an exact counting of the rings, whereby this is made even more difficult by the foreshortening. Therefore, I have used another photo for this, where one has almost a direct view of this area, namely this one of the discarded ET-121 (STS-114), in which one in Hi-Res-Zoom with a little imagination and a sharp eagle eye it is also possible to count out the rings in this front area. Source: NASA For better orientation on the tank, I have numbered the 17 Ice/Frost Ramps, in order to find the exact point for continuing the count up to the Aft Dome. And then the counting went off, but first of all, I had to attach a few markings in order not to constantly have to re-count, when my eyes had gone on strike and lost the orientation. Source: NASA And at this first count I came to 64 rings at the rear end of the Ice/Frost Ramp No. 7, although I have to admit that the counting between the first two ramps was extremely difficult. And then it went on in the other photo exactly at this point Ramp 7 (64), where the count was now increasingly easier. At the end of the tank I came to a total of 132 Rings. What is following now from this for the width of the rings, which is actually the center distance of Valley-to-Valley? Luckily, this calculation is now quite simple if I refer it directly to the length of the Airfix-LH2 tank (without Aft Dome), which is 170 mm, whereby I rounded the number of rings to 130 for the sake of simplicity: 170 mm:130 = 1,3 mm per ring, which would be extrapolated 187 mm, which means 7,4'' at the original ET, which is less than the Peak-to-Peak distance (10'') by Vincent Morales. Now only the Peak height is still missing. But with the distance of 1,3 mm I can now at least determine the best width of the stripes and their distance for my test, possibly 0,75 mm instead of 1 mm with a 0,5 mm tape as a spacer, what I'm going to try on this ET dummy (Ø 50 mm), which I bought at the hardware store. Let's see what comes out of it ...
  2. Hi everyone, since I now know from two experts that I chase after no phantom, now a next step for the implementation of this wave-like ring structure on model ET. As I've said already, there are these two discussed possibilities, either by a 3D printing, if Michael Key finally would have time and desire, or by Scratch-building. Since Michael Key for his 3D model but already should know about what shape and especially what dimensions should have this wavy line, I have now tried to draw a first scetch. Starting from the Peak-to-Valley width of about 5'' = 127 mm = 0,9 mm (1:144) specified by Vincent Morales , which roughly matches my previous estimates from photos, I have sketched the following profile (1:2), which should show this wavelike foam structure, how I could imagine it. Considering that the average SOFI thickness on the ET is approx. 1'' (25,4 mm) , I have drawn a profile whose peak height I assumed with about 0,5'', which with approx. 0,1 mm in 1/144 would be very flat. Now it would be important to find out how large this peak-height actually was at that time in the foam insulation. Let's see if or how Craig Capdepon or Vincent Morales will comment on that, since they should actually remember it.
  3. Hello everybody, at the end of May, my friend Mike (crowe-t) from the ARC Forum asked me, if I could ask Michael Key whether he could also model an Intertank (WSF) for his Airfix STS-135 Shuttle Stack, for what he would have to modify my STS 6-IT only slightly. Since I thought that it would be quite feasible, I asked Michael Key and tried to make it tasty for him, since this would be a useful extension of his store offer and certainly would find even more buyers, since most Shuttle modeler rather would build the later missions. To do this, he would actually only need to remove some details such as the PAL ramps with the Cable trays, as well as the circumferential rings in the Thrust panels, since there were only Ribs, and needs modify the Access door. These changes should make it relatively easy for him to model an IT version for the Super Lightweight Tanks (SLWT) of the later missions from STS-91 (1998), since he has already done the main work. Here is a photo of the ET-138, which was flown at the STS-135, where one can see some of these details, Source: NASA whereby the Access door in the SLWTs was only closed by a Graphite Composite plate , Source: NASA as can be seen here on the ET-122 at the STS-134. Source: NASA After Michael Key had agreed to it and I had discussed with Mike some detail changes back and forth, it was time, and so you can now after the Airfix LWT-IT (1:144) Source: shapeways.com also order the Airfix SLWT-IT (1:144) both in WSF and FUD at Shapeways Source: shapeways.com
  4. roma847

    Launch 14 - Cooper's Rocket

    Hi Rich, I know these Evergreen V-Groove sheets, really an awesome stuff, that fits very well. I think you also know these and similar photos, where one can see these textured sheets on the other sides too, or this one. Just carry on tower building like the Tower of Babel ...
  5. roma847

    Launch 14 - Cooper's Rocket

    Hi Rich, great progress with the service tower. What kind of sheet did you use for the walls, is that an Evergreen sheet?
  6. Hello everybody, in the meantime another expert and friend of Craig Capdepon has joined our Facebook-Dialog, namely Vince Morales (Sr. Staff QA Engineer) from Louisiana, ie a quality assurance specialist, who among others was also involved in the repair of hail damage at the ET-124 (STS-117) in the KSC. And he has spontaneously shared more details on my questions. The rotation of the tank varied during sprays depending on the required SOFI thickness and averaged approximately 2 rpm for the LH2 Tank and up to 6 rpm for the upper part of the LO2 Ogive. As he said the peak to valley was about 5 inches due to the tanks being sprayed in a shingle pattern (barber pole style), what did confirm my estimated approx. spacing between the wavy rings of about 1 mm (1:144). BTW, the Pencil sharpener was only applied to the most affected area at the top of the LO2 Tank during the repair work on the damaged by hail ET-124. Due to the high density of golf ball-sized holes at this point, the entire area had to be repaired, Source: NASA while the rest of the approx. 1.000-2.000 impacts further down in painstaking detail was repaired hole by hole by hand. Source: NASA This amazing tool, mounted on the Lightning Rod on top of the Composite Nose Cone, was be swung all-around for grinding the hand-sprayed SOFI foam. Source: NASA Viewed from up close, one can see that the device was a kind of Multi-belt sander. Source: NASA And with this speckled ET the Atlantis stack came back to the pad, seen here from the west side, Source: NASA and here from the south side, Source: NASA and was then ready for launch again.
  7. Hello everybody, BTW, some friends in the Raumcon forum did mean that this flat wavy ring structure was just an optical effect, but this was a three-dimensional effect, as Craig Capdepon has confirmed. "The SOFI (spray on foam insulation) was applied with automatic spray gun sets on vertical moving rails I think in 3 locations 120 deg. apart around the tank. The tank would rotate and the guns traveled down the rail to apply the desired thickness. The 3 locations were required because the overlap max. time was 45 seconds. We desired the "as sprayed" finished condition because it was more durable when exposed to sunlight and the weather conditions in Florida. There was no attempt to create a "pattern" to the finish. We tried for a smooth uniform finish. The wave like patterns were unique to each tank as a result of the variations in the spray foam insulation process. The spray guns pattern control tip would accumulate a build up of foam causing a less than perfect pattern. There were engineering drawing requirements limiting the peaks and valleys of this finish. The critical area near the nose cone was often machined to obtain a smooth surface using a tool we nicknamed the "pencil sharpener". I found this photo, on which one can see this tool during the repair work of the hail damage on the ET-124 during the start preparations for the STS-117, in which he was involved too. Source: NASA Of course I had asked further questions, including a term "Barber pole", which I found that characterizes the SOFI mode. "It was a non-stop procedure. The tank was rotating as the guns started spraying a predetermined amount of SOFI. Carriages holding the spray guns traveled (down the rail) at a set speed until the end of the spray operation. The correct tank rotation, travel of spray carriages, temperature of SOFI components, pressure of component supplied to guns, substrate temperature, cell environment, (temp. & humidity) and the pattern at the gun pattern control tip all determined the thickness and as sprayed condition of the finished product. "Barber pole" was a shop term to generally refer to the method. The travel of the gun carriages was slow because of the large area (diameter) of the tank. If a smaller cylinder was sprayed (i.e. feed lines) this same method may produce a "spiral-effect" surface." That these rings actually have a three-dimensional structure can also be seen in this video (unfortunately without sound) which shows an SOFI piece of the ET-93 used in the fateful last Columbia mission STS-107. Craig commented about this video: "This was not an optical effect. I would have to see a larger cross section to know exactly where this piece is from. It looks like part of an automatic spray possibly from the aft dome of the LH2 tank. I see two knit lines and it appears the three passes were approx. 1 inch each. SOFI is pliable for about 5 seconds after components are mixed and exit the spray gun. The rough surface in this picture is an example of "roll over" caused when SOFI is formed by an outside force soon after application such as excessive air movement from the direction of the gun." Furthermore, I have learned from him, that he has worked on every shuttle that has flown, what I found next to this photo. "Endeavor the newest shuttle STS-134 (16.05.2011) on the pad. This is ET-122 - we did the mod in February. I've worked on every shuttle that has flown." A very interesting contemporary witness from that time, I have met in this way.
  8. Thanks Rich, I also followed up on exactly this exciting question, and meanwhile I have received a first-hand answer by Craig Capdepon from New Orleans, here during Trimming on ET-122, Source: facebook.com which was flown during the last mission of the Endeavour (STS-134). Source: NASA And so we are now close to the SOFI application. To his Facebook site I came across more or less randomly during my search in the MAF, but thereto and to your thought later more, because that would lead now too far, especially since I got pretty tired now ... ...
  9. Thanks Mark, and Hi everybody, after my successful Ultrasonic cleaning of my FUD-IT I am currently on one of my obligatory voyages of discovery, still looking for the origin of this wavelike SOFI structure of the first generation of ETs, which one can see both on this photo of the ET-33 (STS-36) by George Gassaway, Source: georgesrockets.com as well as on the LO2 tank (ET-137) in this video (5:14) before Discovery's last mission ( STS-133). https://www.youtube.com/watch?v=gD2iT8hSm0k In the meantime, I was following the traces concerning the ET production, which are known to lead directly to the Michoud Assembly Facility (MAF ), popularly NASA's Rocket Factory. Although I have not found any photos of the SOFI Cells, a friend from NSF forum (psloss) has posted an interesting hint to drawings from the assembly process of the tank production. And they come from the PDF Space Shuttle/External Tank System Definition Handbook SLWT, Volume II/2, among others. also this picture here. On it one can see the manufacturing and assembly cells, in which both the priming (Prime) and the SOFI Application of the LH2 and LO2 tanks, as well as the Intertanks took place. From there all ET parts went into the Cell A, where they were assembled vertically. And of this largest cell at that time, I also found an impressive picture by Jester, namely this one, which is linked to the Hi-Res. image, in which one can see a plate at the lower right corner with Cell A. Source: forum.nasaspaceflight.com (Jester) This success made me even more curious, and since I really wanted to find these special SOFI Cells of the MAF, I searched further. The difficulty lies in the fact that Google-searching for SOFI Application & MAF lead almost without exception to actual photos of their equipment there, but it must be noted that in the MAF after the end of the Shuttle-Program 2012/13 all former equipment was dismantled or modified for the bigger tanks of the SLS program, which does not help me much. But in this context, I finally found what I was looking for and found this great photo-combination on which the Cell B & C in Building 110 see before (top) as well as after (below) the dismantling, in which the LH2 tanks got their SOFI-TPS. Source: blogs.nasa.gov Since then, at this lace is standing the new Vertical Assembly Center (VAC) with the world's largest Friction Stir Weld Machine for the production of the larger SLS tanks. So far, so good, but that still left the answerless question of the explanation of the typical wavy SOFI structure of the ETs. As far as I know by now, 90% of the total ET-SOFI insulation was applied with an Automatic Gun Spray System, and only 10% by hand, as can be seen here on the connecting flange between the Intertank and the LO2 tank. Source: NASA But how this automatic system worked in the SOFI cells and how and why this wave-like structure was created during coating still remains a mystery, but which I still want to solve it somehow, why the search goes on ...
  10. Hello everybody, after finally defeating the wretched wax residue of my FUD-IT, now I have to find a solution for the mysterious wavelike SOFI texture on the STS-6 ET-8 surface, what is a further exiting chapter. Source: wikimedia.org And then I'll hope finally to come back to model building ...
  11. roma847

    Launch 14 - Cooper's Rocket

    Very impressive start with the beam framework. Do you have to cut all the profies individually or have you a cutting tool like the Chopper? Source: evergreenscalemodels.com
  12. Thanks Mark, they clean their prints already a bit, but they needed to do it more thoroughly, which would take more time, but time is money ...
  13. Thanks Rich for your nice congrats! Yep, the IT looks clean as a whistle, as the saying goes. If one knows how to do it, Ultrasonic cleaning is really easy, and now I have the know-how, and all of you too ... One either needs sa good equipment, or one has a good dentist with a helpful lab team. BTW, the IT already has its SOFI and is ready for priming and painting.
  14. Hello everybody, after the tough struggle for the rings of the ET now back to the grooves of the last FUD-IT, whose ultrasonic cleaning in the Dental lab was still on the agenda. For that I had procured the recommended intensive cleaner TICKOPUR R 60, which we wanted to use based on the conditions recommended by BANDELIN. Soure: bandelin.com Since this cleaner i.a. Sodium hydroxide (5-15%), also called caustic soda, caution was bidden, which is why protective gloves were required. After the nice colleagues of the ChiliDent Lab were back on board after their short break, it was finally time and the Final Countdown was imminent. In the beginning of May in my #1457 I had presented the critical areas with the strongest wax nests and captured in pictures. In order to shorten the cleaning time, we have increased the concentration of the TICKOPUR to approx. 20 %. Through the rubber ring, the height of the glass insert in the ultrasonic bath could be adjusted so that it hung about 3 cm above the bottom of the tub, which is as important for optimal cleaning as filling the tub with the same solution, that the boss has personally mixed. Due to the size of the glass insert, the Intertank could be inserted lengthwise, which is also advantageous for the cleaning effect. After setting the thermostat to 70 °C, the appliance was switched on by the assistant, and the bath began to bubble. After every 30 minutes, the IT was turned a quarter turn further. Overall, the cleaning time was about three hours. After that, the tank looked white and completely clean, which one could already see at first glance. So finally the work was done, and with a tip into the kitty I thanked me once again and light-hearted said goodbye. And as one can see in this photo, the cleaning was really perfect, because there are no wax residues left, which is why no aftertreatment was required too. This is especially also illustrated by comparing the photos before and afterwards. And here once again a few pictures of both ITs in comparison, where the FUD-IT looks even more filigree than the WSF-IT. Nevertheless, I think that one can use both ITs, depending at whim and purse.
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