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One thing about 3-D printing the innards, I believe it limits what can be coated or left uncoated. Not sure what secret sauce is required, but previous engines of this type relied on some sort of covering to protect engine structures. Matthew
The only question I have from that article concerns the use of heat exchangers. I always thought that you could tap the methane for pressurization right after it exits the regenerative channels and not need an additional heat exchanger for that. Do we know that the methane channel will indeed use an exchanger?
Quote from: Dante80 on 10/03/2016 05:02 pmThe only question I have from that article concerns the use of heat exchangers. I always thought that you could tap the methane for pressurization right after it exits the regenerative channels and not need an additional heat exchanger for that. Do we know that the methane channel will indeed use an exchanger?From looking at the engine, it appears that the methane is tapped right after it comes out of the regenerative cooling circuit of the main combustion chamber and nozzle. Only the oxygen feed has a separate heat exchanger for pressurization gas heating.
Quote from: ellindsey on 10/03/2016 05:16 pmQuote from: Dante80 on 10/03/2016 05:02 pmThe only question I have from that article concerns the use of heat exchangers. I always thought that you could tap the methane for pressurization right after it exits the regenerative channels and not need an additional heat exchanger for that. Do we know that the methane channel will indeed use an exchanger?From looking at the engine, it appears that the methane is tapped right after it comes out of the regenerative cooling circuit of the main combustion chamber and nozzle. Only the oxygen feed has a separate heat exchanger for pressurization gas heating.I see more a tap for the LOX preburner. It is not quite clear now what's the exact schematic.
It appears that Mondaloy is an Aerojet product, so I can imagine that SpaceX would not have access to it.SpaceX and Tesla have hired Charles Kuehmann to lead materials development, so SpaceX probably has its own solution.https://electrek.co/2016/02/24/apple-alloy-expert-tesla-spacex/
Quote from: RedLineTrain on 10/03/2016 06:08 pmIt appears that Mondaloy is an Aerojet product, so I can imagine that SpaceX would not have access to it.SpaceX and Tesla have hired Charles Kuehmann to lead materials development, so SpaceX probably has its own solution.https://electrek.co/2016/02/24/apple-alloy-expert-tesla-spacex/I have been wondering about this. Since SpaceX keeps so much of the details of its tech secret, what other than honor stops them from copying all sorts of proprietary things.Matthew
I think that Musk will be doing and AMA this week or the next. It would be pretty cool to get some more answers about Raptor, especially after the added info we got from this great article. 1. Was the test firing using the full engines' powerpack, or was it only a chamber test?2. Was TEA-TEB used, or a spark igniter (the video I think is inconclusive on that)?3. Will this dev article reach during development the high pressures intended for the ITS Raptor?4. Will the end of development for this 1MN variant involve an acceptance test at Stennis (as per the USAF contract)?
Mr. Belluscio, a very nice article – thank you. One note of correction: the 361s ISP you cite for the first stage's Raptors in vacuum is actually the sea level value for the three inner Raptors of the second stage. See pp. 36 of SpaceX's published PDF.
Quote from: dglow on 10/03/2016 08:42 pmMr. Belluscio, a very nice article – thank you. One note of correction: the 361s ISP you cite for the first stage's Raptors in vacuum is actually the sea level value for the three inner Raptors of the second stage. See pp. 36 of SpaceX's published PDF. I believe that you are misreading the information. Vacuum optimized nozzle can't be used at sea level since they would get into flow separation issues. When they say Sea Level and Vacuum they refer to the two different Raptor versions.There is no way you can get 361 seconds of isp with methane/LOX at sea level. Best I could get was 355 theoretical, without losses, and that was with a Pc of 70MPa. At 30MPa you can't get past 337s.