Meecrob Posted September 23, 2020 Share Posted September 23, 2020 The problem is not how much unwanted roll would be generated, but how do you counteract the unwanted roll? The windward side needs to reliably be kept windward. You could use RCS, but I don't see that bringing any benefit to the design...in fact, as @sevenperforce mentioned above, it removes a redundancy. Quote Link to comment Share on other sites More sharing options...
Spaceception Posted September 23, 2020 Share Posted September 23, 2020 SN8 is getting fins SN1 of Superheavy spotted! Wonder if we'll get some news regarding Raptor before the end of the month. SN50 should be around the corner. Quote Link to comment Share on other sites More sharing options...
RealKerbal3x Posted September 23, 2020 Share Posted September 23, 2020 SN8 flaps! Super Heavy! Eeeeee! Quote Link to comment Share on other sites More sharing options...
RealKerbal3x Posted September 23, 2020 Share Posted September 23, 2020 SN7.1 has popped! Quote Link to comment Share on other sites More sharing options...
Ultimate Steve Posted September 23, 2020 Share Posted September 23, 2020 *pop* goes the Starship! Quote Link to comment Share on other sites More sharing options...
tater Posted September 23, 2020 Share Posted September 23, 2020 What for? Proof testing SN8? Static fire, then gets nose. Quote Link to comment Share on other sites More sharing options...
sevenperforce Posted September 23, 2020 Share Posted September 23, 2020 14 hours ago, Meecrob said: The problem is not how much unwanted roll would be generated, but how do you counteract the unwanted roll? The windward side needs to reliably be kept windward. You could use RCS, but I don't see that bringing any benefit to the design...in fact, as @sevenperforce mentioned above, it removes a redundancy. In the first two designs -- the 12m 2016 ITS and the 9m 2017 MBR -- the vehicle would have had no forward canards and would have used aft split flaps for pitch and roll. Roll would couple with yaw, but that could be handled by RCS, and overall yaw authority would also use RCS while using the aft flaps to maintain constant AoA. The vehicle would be flying at such a high AoA that longitudinal yaw would basically just be rotation around the prograde axis, which is undamped and therefore wouldn't require much expenditure of propellant (as opposed to altering pitch, which would require constant propellant expenditure to fight against the airstream). This would have worked well enough for Earth and Martian entry, actually (see for example the Russian Kliper concept), but terminal descent was very challenging, and it would have been even more challenging to make a descent and landing profile that would work reliably on both Earth and on Mars. That's why they added the forward canards/flaps/squidfins. With both fore and aft control surfaces, there's a much broader range of allowable entry modes and more control during terminal guidance. This, also, is why they had to move the header LOX tank from inside the main LOX tank (original design) to the nose: the forward canards would have made the front end too draggy and not heavy enough, inducing tailspins or total loss of control. 16 hours ago, Spaceception said: SN8 is getting fins IT'S SO FLUFFY 7 hours ago, Ultimate Steve said: *pop* goes the Starship! From viewing, it looked like a circumferential weld failure WITHOUT stress fracture propagation, which I believe is the best of all possible failure modes. Quote Link to comment Share on other sites More sharing options...
RCgothic Posted September 23, 2020 Share Posted September 23, 2020 Aft fins installed! Quote Link to comment Share on other sites More sharing options...
Spaceception Posted September 23, 2020 Share Posted September 23, 2020 @RCgothic Ninja'd But they're testing soon! Looking forward to seeing the forward flaps installed on the nosecone soon. Quote Link to comment Share on other sites More sharing options...
RealKerbal3x Posted September 23, 2020 Share Posted September 23, 2020 4 minutes ago, RCgothic said: Aft fins installed! Remember this? It's back! SN8 will avenge Mk1! Quote Link to comment Share on other sites More sharing options...
sevenperforce Posted September 23, 2020 Share Posted September 23, 2020 1 hour ago, RCgothic said: Aft fins installed! Educated guess about where we go from here: Pressure test with thrust simulator Nose cone completion Raptor mating 3x Static fire 1 Nose cone mating Static fire 2 Flight It makes sense they would pressure test and do the first static fire before mating the nose cone -- less chance of damage if things go south. Quote Link to comment Share on other sites More sharing options...
tater Posted September 23, 2020 Share Posted September 23, 2020 Looking at all those "pathfinder" nosecones lying around, they should transport (barge?) one to Houston, throw it under a tent at JSC, and provide foam core "equipment" with magnets (assuming it was cold-worked, else double sided tape or velcro). Then they can claim to have done all the hard work National team and Dynetics did on their mockups. Quote Link to comment Share on other sites More sharing options...
cubinator Posted September 23, 2020 Share Posted September 23, 2020 10 minutes ago, tater said: Looking at all those "pathfinder" nosecones lying around, they should transport (barge?) one to Houston, throw it under a tent at JSC, and provide foam core "equipment" with magnets (assuming it was cold-worked, else double sided tape or velcro). Then they can claim to have done all the hard work National team and Dynetics did on their mockups. ...and put in a computer in the top for astronauts to train in KSP. Quote Link to comment Share on other sites More sharing options...
tater Posted September 23, 2020 Share Posted September 23, 2020 9 minutes ago, cubinator said: ...and put in a computer in the top for astronauts to train in KSP. They probably can use their own docking sim, what are the chances they don't have a SS version to horse around with? Quote Link to comment Share on other sites More sharing options...
zolotiyeruki Posted September 23, 2020 Share Posted September 23, 2020 19 hours ago, Meecrob said: The problem is not how much unwanted roll would be generated, but how do you counteract the unwanted roll? The windward side needs to reliably be kept windward. You could use RCS, but I don't see that bringing any benefit to the design...in fact, as @sevenperforce mentioned above, it removes a redundancy. I imagine the passive stability enforced by the much larger rear fins would be plenty to minimize the adverse roll effects from the canards. Quote Link to comment Share on other sites More sharing options...
cubinator Posted September 23, 2020 Share Posted September 23, 2020 6 minutes ago, tater said: They probably can use their own docking sim, what are the chances they don't have a SS version to horse around with? They're developing the flight controls and interface now. I wouldn't expect it to be very polished quite yet. Quote Link to comment Share on other sites More sharing options...
tater Posted September 23, 2020 Share Posted September 23, 2020 7 minutes ago, cubinator said: They're developing the flight controls and interface now. I wouldn't expect it to be very polished quite yet. I literally mean the one we played with in a web browser they posted before the first crew mission. https://iss-sim.spacex.com/ (still better than the foam core with a color print out computer screen in the Dynetics lander mock up ) Quote Link to comment Share on other sites More sharing options...
sevenperforce Posted September 23, 2020 Share Posted September 23, 2020 1 hour ago, zolotiyeruki said: I imagine the passive stability enforced by the much larger rear fins would be plenty to minimize the adverse roll effects from the canards. Maybe, but now that I think about it, I am not entirely sure that the forward canards give enough pitch authority. It would be hard to pitch up unless the rear fins were much smaller, in which case you'd lose that roll damping. Quote Link to comment Share on other sites More sharing options...
SOXBLOX Posted September 24, 2020 Share Posted September 24, 2020 (edited) 7 hours ago, sevenperforce said: Educated guess about where we go from here: I've got a better one: Spoiler space! Edited September 24, 2020 by SOXBLOX Quote Link to comment Share on other sites More sharing options...
CatastrophicFailure Posted September 24, 2020 Share Posted September 24, 2020 9 hours ago, tater said: still better than the foam core with a color print out computer screen in the Dynetics lander mock up ) How about the National Team lander’s photocopied switches for... parachutes. Also, closeup of SN7.1’s fate: Quote Link to comment Share on other sites More sharing options...
Scotius Posted September 24, 2020 Share Posted September 24, 2020 It's not total heap of scrap Things are going in the right direction it seems. Quote Link to comment Share on other sites More sharing options...
wumpus Posted September 24, 2020 Share Posted September 24, 2020 20 hours ago, tater said: I literally mean the one we played with in a web browser they posted before the first crew mission. https://iss-sim.spacex.com/ (still better than the foam core with a color print out computer screen in the Dynetics lander mock up ) Don't mock foam core mockups. You can let the astronauts move around and make ECOs before things get too expensive. Ideally you want to make the cheap changes obvious to hide any really expensive changes they might want. Granted, foam core probably works better for people who work with sheet metal (In general the same CAD drawings will print both to "CNC machines"). But you really only want to have to design your carbonfiber molds once. Quote Link to comment Share on other sites More sharing options...
tater Posted September 24, 2020 Share Posted September 24, 2020 8 minutes ago, wumpus said: Don't mock foam core mockups. You can let the astronauts move around and make ECOs before things get too expensive. Ideally you want to make the cheap changes obvious to hide any really expensive changes they might want. Granted, foam core probably works better for people who work with sheet metal (In general the same CAD drawings will print both to "CNC machines"). But you really only want to have to design your carbonfiber molds once. I'm not mocking it, but the PR departments pushing lander play houses as "progress" is funny. I saw a post on twitter of someone actually saying NT and Dynetics were ahead of SpaceX because of these things, lol. I call one ahead when I see actual flight article hardware (even if test hardware). Quote Link to comment Share on other sites More sharing options...
kerbiloid Posted September 24, 2020 Share Posted September 24, 2020 If there were spacemen onboard, they could solder the crack and keep flying. Quote Link to comment Share on other sites More sharing options...
RCgothic Posted September 24, 2020 Share Posted September 24, 2020 41 minutes ago, tater said: I'm not mocking it, but the PR departments pushing lander play houses as "progress" is funny. I saw a post on twitter of someone actually saying NT and Dynetics were ahead of SpaceX because of these things, lol. I call one ahead when I see actual flight article hardware (even if test hardware). Yeah I know who you mean. Quote Link to comment Share on other sites More sharing options...
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