Which ends still with the open question: What are the stats of the BE-3U?
The Expander Bleed is a Gas Generator implementation on the expander cycle: you take a very small amount of propellant (say, 2%), get it as hot as your turbine's blades can take, and after passing them through the turbines you dump it. So, you still inject liquid fuel into the main combustion chamber.
Quote from: Aeneas on 06/25/2020 07:30 pmWhich ends still with the open question: What are the stats of the BE-3U?Blue Origin, at:https://www.blueorigin.com/engines/be-3only tells us that it will produce 710 kN (160,000 lbf) thrust in vacuum, but there is a nice image of the engine on the page that someone might be able to use to reverse-engineer it a bit. Since it is expander bleed cycle, it should have lower ISP than RL-10 and Vinci (which are 460-465 sec), but more thrust. On the other hand it should or could have higher ISP than J-2X (448 sec). Then again, I'm not a combustion engineer, so I could be wrong! There is a chance that BE-3U could end up being a more important engine in future decades than BE-4. - Ed Kyle
Quote from: baldusi on 06/13/2020 01:22 amThe Expander Bleed is a Gas Generator implementation on the expander cycle: you take a very small amount of propellant (say, 2%), get it as hot as your turbine's blades can take, and after passing them through the turbines you dump it. So, you still inject liquid fuel into the main combustion chamber.So no actual gas generator involved. That means that the combustion chamber pressure is not limited to a level that the drive turbine can generate from the heat extracted from the CC. It also means no GG to generate, start or re-start. The lightest, cheapest parts are the ones that aren't there. And that T/W ratio for an LH2 engine is phenomenal
“We’ve continued to improve the RS-68 engine, which today remains the most powerful hydrogen-fueled rocket engine in the world,” said Jim Maser, Aerojet Rocketdyne senior vice president of Space. “This engine was developed entirely with company funds to be a very cost competitive and extremely reliable booster engine.”
IF, big IF, they replaced the ablative nozzle on RS-68 and used 4 of them on SLS, wouldn't they have to have a larger upper stage? This would be because the RS-68's would use more fuel than the RS-25's, right? And IF they used a pair of BE-3U's on say a larger upper stage, wider anyway to leave room for cargo, what would be the SLS payload capability?
Quote from: spacenut on 04/13/2021 01:20 pmIF, big IF, they replaced the ablative nozzle on RS-68 and used 4 of them on SLS, wouldn't they have to have a larger upper stage? This would be because the RS-68's would use more fuel than the RS-25's, right? And IF they used a pair of BE-3U's on say a larger upper stage, wider anyway to leave room for cargo, what would be the SLS payload capability?Remember the original 10 meter rocket, Ares-V? 6 RS-68 engines and dual 5.5 segment SRBs?Core Stage"The 6 RS-68 engines powering the Core will fly at 108 percent power levels (6 percent higher than used on Delta-IV currently) and will each produce 702,055 lbs of thrust and have an Isp of 365 seconds at sea level and will have 797,000 lb of thrust and will have an Isp of 414 seconds in a vacuum." NSF David Harris 4,212,330 million pounds thrust for the 6 core stage engines 5.5 segment SRBs "Each new reusable 5.5 segment SRB, will contain over 1.5 million pounds of propellant which will produce a peak of 3,774,000 million lbs of thrust and will have a vacuum Isp of 275.5 seconds. The 38 percent larger SRB’s will burn for 116 seconds – a full 8 seconds shorter burn time than Space Shuttle – before being jettisoned." NSF David Harris7,548,000 pounds thrust for the booster stageCore Stage + Booster Stage= 4,212,330 + 7,548,000=8,424,660 pounds thrust off the pad. Would have been a monster. The N-1 moon rocket was 10,200,000 lbf/45,400 kN off the pad.
Quote from: Hog on 04/16/2021 05:13 pmQuote from: spacenut on 04/13/2021 01:20 pmIF, big IF, they replaced the ablative nozzle on RS-68 and used 4 of them on SLS, wouldn't they have to have a larger upper stage? This would be because the RS-68's would use more fuel than the RS-25's, right? And IF they used a pair of BE-3U's on say a larger upper stage, wider anyway to leave room for cargo, what would be the SLS payload capability?Remember the original 10 meter rocket, Ares-V? 6 RS-68 engines and dual 5.5 segment SRBs?Core Stage"The 6 RS-68 engines powering the Core will fly at 108 percent power levels (6 percent higher than used on Delta-IV currently) and will each produce 702,055 lbs of thrust and have an Isp of 365 seconds at sea level and will have 797,000 lb of thrust and will have an Isp of 414 seconds in a vacuum." NSF David Harris 4,212,330 million pounds thrust for the 6 core stage engines 5.5 segment SRBs "Each new reusable 5.5 segment SRB, will contain over 1.5 million pounds of propellant which will produce a peak of 3,774,000 million lbs of thrust and will have a vacuum Isp of 275.5 seconds. The 38 percent larger SRB’s will burn for 116 seconds – a full 8 seconds shorter burn time than Space Shuttle – before being jettisoned." NSF David Harris7,548,000 pounds thrust for the booster stageCore Stage + Booster Stage= 4,212,330 + 7,548,000=8,424,660 pounds thrust off the pad. Would have been a monster. The N-1 moon rocket was 10,200,000 lbf/45,400 kN off the pad.Actually, it's 11,760,330 pounds of thrust (~52,313 kilonewtons).
Quote from: ZachS09 on 04/17/2021 03:03 amQuote from: Hog on 04/16/2021 05:13 pmQuote from: spacenut on 04/13/2021 01:20 pmIF, big IF, they replaced the ablative nozzle on RS-68 and used 4 of them on SLS, wouldn't they have to have a larger upper stage? This would be because the RS-68's would use more fuel than the RS-25's, right? And IF they used a pair of BE-3U's on say a larger upper stage, wider anyway to leave room for cargo, what would be the SLS payload capability?Remember the original 10 meter rocket, Ares-V? 6 RS-68 engines and dual 5.5 segment SRBs?Core Stage"The 6 RS-68 engines powering the Core will fly at 108 percent power levels (6 percent higher than used on Delta-IV currently) and will each produce 702,055 lbs of thrust and have an Isp of 365 seconds at sea level and will have 797,000 lb of thrust and will have an Isp of 414 seconds in a vacuum." NSF David Harris 4,212,330 million pounds thrust for the 6 core stage engines 5.5 segment SRBs "Each new reusable 5.5 segment SRB, will contain over 1.5 million pounds of propellant which will produce a peak of 3,774,000 million lbs of thrust and will have a vacuum Isp of 275.5 seconds. The 38 percent larger SRB’s will burn for 116 seconds – a full 8 seconds shorter burn time than Space Shuttle – before being jettisoned." NSF David Harris7,548,000 pounds thrust for the booster stageCore Stage + Booster Stage= 4,212,330 + 7,548,000=8,424,660 pounds thrust off the pad. Would have been a monster. The N-1 moon rocket was 10,200,000 lbf/45,400 kN off the pad.Actually, it's 11,760,330 pounds of thrust (~52,313 kilonewtons).Excellent, do you happen to have a quick breakdown of the core vs booster thrust? I can't seem to find an off the pad/sea level thrust figure for the 5.5 segment boosters.This read agrees with you stating 5306 tonnes/11,697,727 pounds/thrust/52,034kN.""One Later Design - Six RS-68s and Two 5.5 SRBsOn June 23, 2008, NASA's Constellation Program Manager Jeff Hanley announced that the Ares V baseline design had grown larger and more powerful than previous designs. The trans-lunar insertion (TLI) capability had risen to 71 tonnes, a 7 tonne increase. The theoretical Low Earth Orbit (LEO) payload had grown to 145 tonnes or more from the previous 130-ish tonnes (see Table 1 for Details).Planners added a sixth RS-68 engine to the core stage and specified a pair of five-and-a-half segment solid rocket boosters. The previous design used five RS-68s and two five-segment boosters. The core stage was lengthened. The Earth Departure Stage (EDS) diameter had already been increased to 10 meters to match the core diameter during recent design iterations. The payload fairing diameter also grew to 10 meters. Overall height jumped to 116.16 meters, 5.56 meters taller than Saturn V. Liftoff weight increased to 3,699.23 tonnes and liftoff thrust to an unprecedented 5,306 tonnes. """https://www.spacelaunchreport.com/ares5.html
Quote from: Hog on 04/20/2021 02:35 pmQuote from: ZachS09 on 04/17/2021 03:03 amQuote from: Hog on 04/16/2021 05:13 pmQuote from: spacenut on 04/13/2021 01:20 pmIF, big IF, they replaced the ablative nozzle on RS-68 and used 4 of them on SLS, wouldn't they have to have a larger upper stage? This would be because the RS-68's would use more fuel than the RS-25's, right? And IF they used a pair of BE-3U's on say a larger upper stage, wider anyway to leave room for cargo, what would be the SLS payload capability?Remember the original 10 meter rocket, Ares-V? 6 RS-68 engines and dual 5.5 segment SRBs?Core Stage"The 6 RS-68 engines powering the Core will fly at 108 percent power levels (6 percent higher than used on Delta-IV currently) and will each produce 702,055 lbs of thrust and have an Isp of 365 seconds at sea level and will have 797,000 lb of thrust and will have an Isp of 414 seconds in a vacuum." NSF David Harris 4,212,330 million pounds thrust for the 6 core stage engines 5.5 segment SRBs "Each new reusable 5.5 segment SRB, will contain over 1.5 million pounds of propellant which will produce a peak of 3,774,000 million lbs of thrust and will have a vacuum Isp of 275.5 seconds. The 38 percent larger SRB’s will burn for 116 seconds – a full 8 seconds shorter burn time than Space Shuttle – before being jettisoned." NSF David Harris7,548,000 pounds thrust for the booster stageCore Stage + Booster Stage= 4,212,330 + 7,548,000=8,424,660 pounds thrust off the pad. Would have been a monster. The N-1 moon rocket was 10,200,000 lbf/45,400 kN off the pad.Actually, it's 11,760,330 pounds of thrust (~52,313 kilonewtons).Excellent, do you happen to have a quick breakdown of the core vs booster thrust? I can't seem to find an off the pad/sea level thrust figure for the 5.5 segment boosters.This read agrees with you stating 5306 tonnes/11,697,727 pounds/thrust/52,034kN.""One Later Design - Six RS-68s and Two 5.5 SRBsOn June 23, 2008, NASA's Constellation Program Manager Jeff Hanley announced that the Ares V baseline design had grown larger and more powerful than previous designs. The trans-lunar insertion (TLI) capability had risen to 71 tonnes, a 7 tonne increase. The theoretical Low Earth Orbit (LEO) payload had grown to 145 tonnes or more from the previous 130-ish tonnes (see Table 1 for Details).Planners added a sixth RS-68 engine to the core stage and specified a pair of five-and-a-half segment solid rocket boosters. The previous design used five RS-68s and two five-segment boosters. The core stage was lengthened. The Earth Departure Stage (EDS) diameter had already been increased to 10 meters to match the core diameter during recent design iterations. The payload fairing diameter also grew to 10 meters. Overall height jumped to 116.16 meters, 5.56 meters taller than Saturn V. Liftoff weight increased to 3,699.23 tonnes and liftoff thrust to an unprecedented 5,306 tonnes. """https://www.spacelaunchreport.com/ares5.htmlThat, I never thought of yet. And I honestly don’t know what the “off the pad/sea level thrust” thing means.