DocM Posted September 26, 2016 Author Share Posted September 26, 2016 BOTE, I'm guessing about 15 meters wide by 75-80 meters tall for the BFS lower stage. Betting BFS will be both the upper stage and the vehicle. A 4:1 aspect ratio would make BFS about 60 meters long, which means a stack 135-140 meters tall. Unobscured Vision 1 Share Link to comment Share on other sites More sharing options...
Unobscured Vision Posted September 26, 2016 Share Posted September 26, 2016 Yep. 15 meter hull, likely vertical assembly. No way they'll be able to do an erector from horizontal with something this size, even dry mass. Draggendrop 1 Share Link to comment Share on other sites More sharing options...
DocM Posted September 26, 2016 Author Share Posted September 26, 2016 (edited) And no way is it a 10-13 meter hull. It'd take a stack 150 meters (~500 feet) tall to hold the propellants, and there's not enough base area to hold 20+ engines with 4.2 meter nozzles. Unobscured Vision 1 Share Link to comment Share on other sites More sharing options...
DocM Posted September 26, 2016 Author Share Posted September 26, 2016 Looking like a ~4 meter nozzle for the vacuum Raptor, and just under 2 meters for the sea level Raptor. The combustion chamber won't be much larger that a Merlin 1D's, more than 3x the pressure, but that dual multi-staged pumping system is going to be something to behold. We ain't in Kansas anymore. Unobscured Vision and Draggendrop 2 Share Link to comment Share on other sites More sharing options...
DocM Posted September 26, 2016 Author Share Posted September 26, 2016 (edited) Looks like SpaceX updated the Raptor Wikipedia page - added proprietary info like mix ratio and more accurate thrust numbers. Raptor Propellants: LOX/liquid methane Mixture ratio: 3.8:1 Cycle: Full-Flow Staged Combustion Pumps: 2× multi-stage Chambers: 1 Chamber pressure: 30 MPa (4,400 psi) Sea level performance Thrust (S/L): 2.7 MN (610,000 lbf) Isp (S/L): 321 seconds Nozzle ratio: ?? (likely 50ish) Nozzle diameter: ?? (likely <2 meters) Vacuum performance Thrust (vacuum): 3 MN (670,000 lbf) Isp (vacuum): 362 seconds Nozzle ratio: 150 Nozzle diameter: ~4 meters (13 ft) Unobscured Vision and Draggendrop 2 Share Link to comment Share on other sites More sharing options...
DocM Posted September 26, 2016 Author Share Posted September 26, 2016 Typo correction Isp (vacuum): 382 seconds Unobscured Vision 1 Share Link to comment Share on other sites More sharing options...
Unobscured Vision Posted September 27, 2016 Share Posted September 27, 2016 Yeah, we always lose about 10% at SL. That's the way of things ... I stand by what I said though ... watching a night launch will be uncomfortable. Watching it in the daytime might be too. Two-dozen-plus Raptors going off at once is gonna be bright. DocM and Draggendrop 2 Share Link to comment Share on other sites More sharing options...
Draggendrop Veteran Posted September 27, 2016 Veteran Share Posted September 27, 2016 67th IAC calendar of events 151 page pdf for the 67th IAC, 2016 I really wish I was there...way too cool... Unobscured Vision 1 Share Link to comment Share on other sites More sharing options...
DocM Posted September 27, 2016 Author Share Posted September 27, 2016 Musk corrected himself about the production Raptor area ratio. @elonmusk @rocketrepreneur Meant to say 200 AR for production vac engine. Dev will be up to 150. Beyond that, too much flow separation in Earth atmos. Link to comment Share on other sites More sharing options...
Beittil Posted September 27, 2016 Share Posted September 27, 2016 Internet breaking day is upon us Draggendrop and DocM 2 Share Link to comment Share on other sites More sharing options...
+John. Subscriber¹ Posted September 27, 2016 Subscriber¹ Share Posted September 27, 2016 It's here! I've only been waiting since February! SALSN, Draggendrop and DocM 3 Share Link to comment Share on other sites More sharing options...
DocM Posted September 27, 2016 Author Share Posted September 27, 2016 18:30 UTC. Link to comment Share on other sites More sharing options...
Draggendrop Veteran Posted September 27, 2016 Veteran Share Posted September 27, 2016 50 minutes to "showtime"....xmas in September.... Jim K 1 Share Link to comment Share on other sites More sharing options...
anthdci Posted September 27, 2016 Share Posted September 27, 2016 that video! Link to comment Share on other sites More sharing options...
Beittil Posted September 27, 2016 Share Posted September 27, 2016 (edited) Initial response... Draggendrop and DocM 2 Share Link to comment Share on other sites More sharing options...
DocM Posted September 27, 2016 Author Share Posted September 27, 2016 Draggendrop and Unobscured Vision 2 Share Link to comment Share on other sites More sharing options...
anthdci Posted September 27, 2016 Share Posted September 27, 2016 mind blown if they pull this off! Draggendrop 1 Share Link to comment Share on other sites More sharing options...
FloatingFatMan Posted September 27, 2016 Share Posted September 27, 2016 Hurry up! Stupid minutes and seconds ticking by so slowly! Draggendrop 1 Share Link to comment Share on other sites More sharing options...
DocM Posted September 27, 2016 Author Share Posted September 27, 2016 (edited) 42 engines on BFR is about 28 million pounds of liftoff thrust. Boosback Unobscured Vision and Draggendrop 2 Share Link to comment Share on other sites More sharing options...
Beittil Posted September 27, 2016 Share Posted September 27, 2016 Draggendrop 1 Share Link to comment Share on other sites More sharing options...
anthdci Posted September 27, 2016 Share Posted September 27, 2016 thats smaller than the 15m predicted... those engines must be packed pretty tight Link to comment Share on other sites More sharing options...
DocM Posted September 27, 2016 Author Share Posted September 27, 2016 (edited) I figured 15m for 30 or less engines, but 12m for 42? Differential throttle steering? Link to comment Share on other sites More sharing options...
Beittil Posted September 27, 2016 Share Posted September 27, 2016 Le Meh... Link to comment Share on other sites More sharing options...
DocM Posted September 27, 2016 Author Share Posted September 27, 2016 28 km/s , about a 25 day transit. SALSN 1 Share Link to comment Share on other sites More sharing options...
Draggendrop Veteran Posted September 27, 2016 Veteran Share Posted September 27, 2016 Link to comment Share on other sites More sharing options...
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