sevenperforce Posted December 14, 2023 Share Posted December 14, 2023 1 hour ago, tater said: That is a CHONKY boi. Quote Link to comment Share on other sites More sharing options...
Spaceception Posted December 14, 2023 Share Posted December 14, 2023 Instagram has an interior shot which looks like it includes a new second stage. https://www.instagram.com/p/C01geu4LksD/?igshid=MjM0N2Q2NDBjYg== Quote Link to comment Share on other sites More sharing options...
tater Posted December 14, 2023 Author Share Posted December 14, 2023 32 minutes ago, Spaceception said: Instagram has an interior shot which looks like it includes a new second stage. https://www.instagram.com/p/C01geu4LksD/?igshid=MjM0N2Q2NDBjYg== Quote Link to comment Share on other sites More sharing options...
Spaceception Posted December 14, 2023 Share Posted December 14, 2023 (edited) 3 hours ago, tater said: Thanks, I'm on my phone. According to Lapsa, it's not the full length first stage tank. Edited December 14, 2023 by Spaceception Quote Link to comment Share on other sites More sharing options...
tater Posted December 14, 2023 Author Share Posted December 14, 2023 6 minutes ago, Spaceception said: Thanks, I'm on my phone. I had to grab the image and rehost it. Quote Link to comment Share on other sites More sharing options...
sevenperforce Posted December 15, 2023 Share Posted December 15, 2023 7 hours ago, Spaceception said: Thanks, I'm on my phone. According to Lapsa, it's not the full length first stage tank. Ah, yep, that makes sense. I was going to be pretty shocked if the fineness was THAT low. I could see it for a hydrolox rocket but not for methalox. Quote Link to comment Share on other sites More sharing options...
SunlitZelkova Posted December 15, 2023 Share Posted December 15, 2023 15 hours ago, tater said: Nice. Moses Lake is not that far north. When I lived in the Seattle area, my middle school satellite club (really weather balloon club) stopped there for a potty break and stretching the legs after having recovered the balloons a few tens of miles to the east. Very cool to have rocket development going on so close to home. Southern California and, of course, Texas and Florida feel so distant from Oregon. Quote Link to comment Share on other sites More sharing options...
AckSed Posted December 15, 2023 Share Posted December 15, 2023 We going to see cold boom? Quote Link to comment Share on other sites More sharing options...
tater Posted December 16, 2023 Author Share Posted December 16, 2023 Quote Link to comment Share on other sites More sharing options...
AckSed Posted December 17, 2023 Share Posted December 17, 2023 Aww, no boom. Wonder why it wasn't full-size: lack of space in the workshop? Quote Link to comment Share on other sites More sharing options...
Scotius Posted December 17, 2023 Share Posted December 17, 2023 Probably money saving measure. Why crumple 12 meter tank if you can get the same data from destroying 8 meter one? Quote Link to comment Share on other sites More sharing options...
darthgently Posted December 17, 2023 Share Posted December 17, 2023 1 hour ago, Scotius said: Probably money saving measure. Why crumple 12 meter tank if you can get the same data from destroying 8 meter one? The structural characteristics will be fairly different for compression, pressure, tension, etc, but if they are confident in their ability to model and translate/extrapolate the test result numbers from one form to the other then it's useful to them I suppose Quote Link to comment Share on other sites More sharing options...
Pthigrivi Posted December 18, 2023 Share Posted December 18, 2023 (edited) 8 hours ago, darthgently said: The structural characteristics will be fairly different for compression, pressure, tension, etc, but if they are confident in their ability to model and translate/extrapolate the test result numbers from one form to the other then it's useful to them I suppose Hmm good question... if you have a pressurized cylinder are the hoop stresses any different along the length? I wouldn't think so but I could be wrong. Edited December 18, 2023 by Pthigrivi Quote Link to comment Share on other sites More sharing options...
cubinator Posted December 18, 2023 Share Posted December 18, 2023 55 minutes ago, Pthigrivi said: Hmm good question... if you have a pressurized cylinder are the hoop stresses any different along the length? I wouldn't think so but I could be wrong. The only thing that would make a difference is if your cylinder has different properties along the length. Quote Link to comment Share on other sites More sharing options...
darthgently Posted December 18, 2023 Share Posted December 18, 2023 If all you are testing is pressure, then no issue detected. But if testing lengthwise compression as in SpaceX's "can crusher" wouldn't the different length play a role in the force at which it may buckle? Quote Link to comment Share on other sites More sharing options...
Spaceception Posted January 4 Share Posted January 4 (edited) I found an interview from last January. From what I could tell, it wasn't linked here. I haven't finished it, and it might not have anything new, especially since it looks like something done for high school students (the interviewer is a physics teacher), but I thought it was interesting to share. Katherine Cruz (the Stoke engineer being interviewed) works on their test site. As a general question that I don't believe I've seen an answer for, have they talked about the decision to use hydrogen for the regenerative heatshield? Is it simply impractical, at least on a vehicle this size, to use methane instead? Additionally, it looks like there's going to be a new interview with Andy Lapsa on NSF, maybe new info (fingers crossed for engine development on the first stage)? Edited January 5 by Spaceception January, not Janurary, I blame being sick. Also NSF Quote Link to comment Share on other sites More sharing options...
StrandedonEarth Posted January 5 Share Posted January 5 (edited) LH2 has a higher specific heat than methane, so it’s more effective at cooling the heat shield. I’d cite my source, but it’s tricky on mobile; I just asked Siri and by the graphs it appears H2 is better 2 hours ago, Spaceception said: I found an interview from last January. From what I could tell, it wasn't linked here. I haven't finished it, and it might not have anything new, especially since it looks like something done for high school students (the interviewer is a physics teacher), but I thought it was interesting to share. Katherine Cruz (the Stoke engineer being interviewed) works on their test site. As a general question that I don't believe I've seen an answer for, have they talked about the decision to use hydrogen for the regenerative heatshield? Is it simply impractical, at least on a vehicle this size, to use methane instead? Additionally, it looks like there's going to be a new interview with Andy Lapsa on NSF, maybe new info (fingers crossed for engine development on the first stage)? Edited January 5 by StrandedonEarth Formatting… Quote Link to comment Share on other sites More sharing options...
Spaceception Posted January 5 Share Posted January 5 (edited) 2 hours ago, StrandedonEarth said: LH2 has a higher specific heat than methane, so it’s more effective at cooling the heat shield. I’d cite my source, but it’s tricky on mobile; I just asked Siri and by the graphs it appears H2 is better I figured that much, I didn't have specific heat on the top of my head though. But that aside, could it be effective enough if you used methane instead, or do the drawbacks outweigh any sort of commonality? This kind of graph? table? Hydrogen is ~2.5x better on a MJ/kg basis, so you need more propellent to cool the same amount, but is it significant enough to be a show stopper? Hydrogen needs a higher mass ratio compared to methane for the same delta-v, so I'm wondering if it evens out at all. Edited January 5 by Spaceception Quote Link to comment Share on other sites More sharing options...
AckSed Posted January 5 Share Posted January 5 I think methane could work, but there could be a side-benefit to hydrogen that Stoke is depending on: its low density means large tanks, which means that the second stage is also low-density and slows down much more quickly upon re-entry. I don't know where the constraints are any more than I know how good methane is for cooling, but Rocket Lab's Peter Beck has stated that small launchers can be incredibly tight on mass margins. It might be a series of requirements: IF hydrogen AND low-density second stage EQUALS low consumption of fuel for cooling heatshield PLUS lighter heatshield AND high vacuum specific impulse... THEN hydrogen. Quote Link to comment Share on other sites More sharing options...
Spaceception Posted January 5 Share Posted January 5 2 minutes ago, AckSed said: I don't know where the constraints are any more than I know how good methane is for cooling, but Rocket Lab's Peter Beck has stated that small launchers can be incredibly tight on mass margins. Yes, there's that as well, so if it is possible, it could be used on a larger successor to Nova that has those margins. Like how SpaceX discarded full reusability for Falcon 9 and went up to Starship. The low density being a possible benefit is a good point though! Quote Link to comment Share on other sites More sharing options...
sevenperforce Posted January 5 Share Posted January 5 11 hours ago, AckSed said: It might be a series of requirements: IF hydrogen AND low-density second stage EQUALS low consumption of fuel for cooling heatshield PLUS lighter heatshield AND high vacuum specific impulse... THEN hydrogen. Also, keep in mind: a lot of start ups gravitate toward kerosene for their first stage (or even solids). Because of the high density of kerosene, you tend to have a much thinner rocket. Not only are they going for full reusability, but they want a methane first stage, so it makes sense to use a wider stage due to methane’s low density, which in turn gives them more volume to work with for their hydrogen upper stage. Quote Link to comment Share on other sites More sharing options...
Spaceception Posted January 23 Share Posted January 23 (edited) And the video! They're really moving quickly. And according to this video (shared on the Stoke subreddit, I didn't watch it), they're planning for a full hot fire of the engine early next year Edited January 23 by Spaceception Added the video of the test Quote Link to comment Share on other sites More sharing options...
darthgently Posted January 23 Share Posted January 23 55 minutes ago, Spaceception said: They're really moving quickly. And according to this video (shared on the Stoke subreddit, I didn't watch it), they're planning for a full hot fire of the engine early next year If they don't have "Get Stoked" + logo items in their merch store I'm going to be disappointed. Because I want a hat Quote Link to comment Share on other sites More sharing options...
Spaceception Posted January 23 Share Posted January 23 4 minutes ago, darthgently said: If they don't have "Get Stoked" + logo items in their merch store I'm going to be disappointed. Because I want a hat There's a hoodie with their old colored flames logo that Andy Lapsa was wearing in his EDA interview, but they don't have it on the store. I don't know if it was an exclusive design, or they just stopped selling it when they updated the logo and stuff. Quote Link to comment Share on other sites More sharing options...
darthgently Posted January 23 Share Posted January 23 Yeah, not seeing anything must-have in the shop. If the fitted cap had Get Stoked on it, I'd have a tracking number by now, lol https://shop.stokespace.com Quote Link to comment Share on other sites More sharing options...
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