Hello guys!I was thinking, a thickened common dome would allow higher pressure differentials in the two tanks. Maybe it is a benefit during pressure tests, or even normal tanking procedures.About the tapered sheet rolling:I think it is harder than it seems. On the thinner side the excess material has to "go" somewhere and the result is an axially curved sheet.
Quote from: Coastal Ron on 11/28/2019 02:24 amQuote from: Eka on 11/28/2019 02:11 amThat shipment of plates of stainless steel bocachicagal got photos of this morning are curved in 3D and cut into truncated pie wedges or circles. I wonder if some are for the nose cone, and others bulkheads.Not sure if all of the pieces are there, but it looks like the piece on top is the circular top to the dome, and the other 3D formed pieces are the sides leading up to the circular top.And they all look rather substantially thick, which leads me to think that they are beefing up the strength of at least the dome.There are two different types of plates. The big plates look to be about 4x the thickness of the small ones. Beefing up the domes could be in the plans but they look too thick. Without formal pixel count, and taking the trailer DOT tape as 50mm wide, they look ~12-14mm or thereabouts. The dome didn’t fail, it was the outer wall. Is this thickness called for?Could they be forms or proof pieces? Or maybe a new take on the thrust structure?We also had those plates with tabs on the corners. Where do they fit in?Phil
Quote from: Eka on 11/28/2019 02:11 amThat shipment of plates of stainless steel bocachicagal got photos of this morning are curved in 3D and cut into truncated pie wedges or circles. I wonder if some are for the nose cone, and others bulkheads.Not sure if all of the pieces are there, but it looks like the piece on top is the circular top to the dome, and the other 3D formed pieces are the sides leading up to the circular top.And they all look rather substantially thick, which leads me to think that they are beefing up the strength of at least the dome.
That shipment of plates of stainless steel bocachicagal got photos of this morning are curved in 3D and cut into truncated pie wedges or circles. I wonder if some are for the nose cone, and others bulkheads.
Quote from: Nomadd on 11/29/2019 02:23 pmQuote from: spacenut on 11/29/2019 02:18 pmCoils are limited in length to transport size. Right now a coil that SpaceX receives is only a few feet longer than the individual rings. So spiraling will not really solve anything. Not much scrap so the little there is can be used for fins etc. So if Starship needs a thicker skin on the bottom for legs, fins, engine mounts, etc, but thinner at top. A spiral would not solve that problem. Right now a coil of stainless steel is about 2m x 30m in length for road transport. It takes about 28.5m in length to make one ring. Only about 1.5m is left. Spiraling would only complicate matters. Just trim the end off to make each ring and use the scrap for something else. An easier solution would be to get the factory to trim to the exact length, so perfect coils can be made in the field. Way off. You need to figure those coil lengths again.Huh? 9m x Pi = ~28.3m, how is that way off?
Quote from: spacenut on 11/29/2019 02:18 pmCoils are limited in length to transport size. Right now a coil that SpaceX receives is only a few feet longer than the individual rings. So spiraling will not really solve anything. Not much scrap so the little there is can be used for fins etc. So if Starship needs a thicker skin on the bottom for legs, fins, engine mounts, etc, but thinner at top. A spiral would not solve that problem. Right now a coil of stainless steel is about 2m x 30m in length for road transport. It takes about 28.5m in length to make one ring. Only about 1.5m is left. Spiraling would only complicate matters. Just trim the end off to make each ring and use the scrap for something else. An easier solution would be to get the factory to trim to the exact length, so perfect coils can be made in the field. Way off. You need to figure those coil lengths again.
Coils are limited in length to transport size. Right now a coil that SpaceX receives is only a few feet longer than the individual rings. So spiraling will not really solve anything. Not much scrap so the little there is can be used for fins etc. So if Starship needs a thicker skin on the bottom for legs, fins, engine mounts, etc, but thinner at top. A spiral would not solve that problem. Right now a coil of stainless steel is about 2m x 30m in length for road transport. It takes about 28.5m in length to make one ring. Only about 1.5m is left. Spiraling would only complicate matters. Just trim the end off to make each ring and use the scrap for something else. An easier solution would be to get the factory to trim to the exact length, so perfect coils can be made in the field.
Nomadd was getting at the length of stock in a coil, not the stock length needed for a ring. A couple months ago I calculated the length of stock on a coil of some diameter, with a center void of some diameter, in 1mm thickness increments from 1-5mm. I’ll look for the post or rerun the numbers when I get a chance. IIRC even the 5mm had over 1000m of stock on it. These were theoretical numbers and did not take truck weight limits into account.Phil
The truck bed is 102” wide and the 4x4 blocking is full width. By eyeball I name up with a coil width of ~84” or 2.134m. Fudging that back to an even 2m feels right to me.If nobody has a better number I’ll go with that and use it to estimate coil width and core hole diameter from another pic. From the trailer sag it is a heavy load. There are two coils.I’ll also check on the density of 301 and use that for a sanity check. From this I’ll get stock length. An assumption here is that this is 301 or the new formulation is close in density. Can somebody give me a good range for reasonable thicknesses?Phil
Quote from: fael097 on 11/29/2019 05:36 pmlooks like the new steel rolls are from the same company that made the previous ones (outokumpu). not so sure about the much anticipated spaceX custom stainless steel alloy, seems to me that they're not changing the material for mk3.I can imagine Tesla having a foundry / facility to manufacture starship quantities of 30X (nor 250k+ Cybertruck quantities). Therefore I was wondering if Tesla developed the material but outsourced its production...
looks like the new steel rolls are from the same company that made the previous ones (outokumpu). not so sure about the much anticipated spaceX custom stainless steel alloy, seems to me that they're not changing the material for mk3.
I find 500'-1000' hard to believe. I figure 300' tops, but I still believe those rolls are only about 100' long. Another problem with spiraling. If you do have to have a long roll to spiral from top to bottom. The diameter may be too large to transport. Another reason for roll limits is road transportation due to weight. How much does one of those coils weigh? You also have lifting equipment limits and handling equipment limits. I have seen coils of steel like this come off a railroad car. Then it was stretched out by a machine, then bent around by another to make pipe. The pipe was cut at 42' lengths. One coil of steel made about 3 lengths of pipe. The pipe was only about 1/4" of an inch thick. This is why I don't think the rolls are over 100'. If tightly rolled, maybe 200'. I just don't think existing steel roll handling equipment is adequate for spiral welding. I also don't think Elon is going to go to the expense of making special equipment or building it to handle spiral welding. He already said he wasn't. I'm just trying to point out the 100's of reasons why spiraling long wide steel Starships would be cost prohibitive if you are on a tight budget.
A flatbed with a highway tractor w/sleeper berth will haul ~48,000lb or a bit under 21.8 metric tons. There are two coils per load.I don’t know why the yield on that pipe fab was so low but I’m sure I calculated over 1000m length on some normally sized coil for a 5mm thickness. A quarter inch would be ~6.4mm. I’ll run the numbers later based on the coils seen today and we can all poke at them. I do make the occasional mistake but disremember when that last happened. Just out of curiosity, what was the nominal size on the pipe you’re talking about?Phil
Quote from: OTV Booster on 11/29/2019 08:16 pmThe truck bed is 102” wide and the 4x4 blocking is full width. By eyeball I name up with a coil width of ~84” or 2.134m. Fudging that back to an even 2m feels right to me.If nobody has a better number I’ll go with that and use it to estimate coil width and core hole diameter from another pic. From the trailer sag it is a heavy load. There are two coils.I’ll also check on the density of 301 and use that for a sanity check. From this I’ll get stock length. An assumption here is that this is 301 or the new formulation is close in density. Can somebody give me a good range for reasonable thicknesses?Philnot sure if the roll width represents the actual width of the steel sheet, or if it could have some padding, but the mk3 ring in the tent is exactly 70" (177.8cm) tall, same height as mk2 and mk4 rings.edit: a quick pixel count, assuming the flat bed width you mentioned, gave me a coil width of 180.9cm. as expected, within toleranceno quick way (for me) to determine steel thickness from these images though
The max width on those coils is 74”. ID is either 20” or 24”, depending on the segments used on the mandrel. I think the thickness they’re using was 4 mm. If the OD is 50” (rough guess from the photo), the coil would weigh roughly 20 tons. Standard, not metric. If all that is correct, the coil would be roughly 1000 ft long.I can’t see space x investing the money to run this material themselves. That would require $1.5B + investment and a lot of people to run the site
Quote from: OTV Booster on 11/29/2019 08:16 pmThe truck bed is 102” wide and the 4x4 blocking is full width. By eyeball I name up with a coil width of ~84” or 2.134m. Fudging that back to an even 2m feels right to me.If nobody has a better number I’ll go with that and use it to estimate coil width and core hole diameter from another pic. From the trailer sag it is a heavy load. There are two coils.I’ll also check on the density of 301 and use that for a sanity check. From this I’ll get stock length. An assumption here is that this is 301 or the new formulation is close in density. Can somebody give me a good range for reasonable thicknesses?PhilNomadd took pictures of steel coils a week or so ago. They were labeled 2mm, 3mm and 4mm. This jives with thicknesses needed to resist hoop tension and head pressures.Assuming 2 coils per flatbed semi, OD=40in, ID=16in, W=78in, Wt=23325lbLength at thickness length 2 mm (.079 in) 1113 ft 3 mm (.118 in) 745 ft 4 mm (.157 in) 560 fthttps://www.carsley.com/Utilities/Steel-Coil-CalculatorsEdit: BTW, we got permission to post these thicknesses on the public side.John
Thanks, it’s kind of weird that I stumbled across this today. I actually work at the facility and in the department that trims these coils to width. I think we ran some 2 mm thick, but I know the majority has been 4 mm. I found this because I was googling what the 30x stood for that they plan to use in their cybertruck. I see there has been discussions about that too
The max width on those coils is 74”. ID is either 20” or 24”, depending on the segments used on the mandrel. I think the thickness they’re using was 4 mm. If the OD is 50” (rough guess from the photo), the coil would weigh roughly 20 tons. Standard, not metric. If all that is correct, the coil would be roughly 1000 ft long.I can’t see space x investing the money to run this material themselves. That would require $1.5B + investment and a lot of people to run the siteFor the sake of correct nomenclature, those are coils, not rolls. Rolls are what you use to roll coils and sheets of stainless
A morning delivery. I saw it parked off the road at the big dish area, on LBJ and then it was taken to the assembly area.