Jump to content

UmbralRaptor

Members
  • Posts

    1,582
  • Joined

  • Last visited

Everything posted by UmbralRaptor

  1. My rule of thumb is that any engine that burns all the way from surface to orbit gets 80% of its vacuum Isp. Eg: an LV-T30 (320 - 370 s) would get 360 s, and a Mainsail (280 - 330 s) would get 320 s. For stages that burn only partway, it's more of a best guess thing, depending on what altitudes are involved, how many stages to orbit, etc. Anything that doesn't start burning until >10 km will get >90% of its vacuum Isp anyway...
  2. There are design ranges where craft using lighter low Isp engines outperform heavier high Isp ones. That said, I would expect anything using the Mk2 lander can and a rockomaxx x32-800 to push you outside of that.
  3. The Hitchhiker pod sounds like it would cover this. As would EVAing a few kerbals from one of the capsules.
  4. The breakingFroce and breakingTorque listed in the part.cfg are relatively low (150), but I've never had issues with it. Usually other parts fail first.
  5. It's doable provided either the center or outboard engines are not directly connected to the tanks (say, separated by decouplers). Then it's possible to run fuel lines from the unconnected tanks to the connected ones, and from the connected tanks to the unconnected engines. I ran into similar issues when designing an Atlas clone.
  6. The top of Kerbin's atmosphere is ~69,078 m. There is currently no reentry heat, and aerodynamic forces will only rip panels apart once you're fairly low. That said, a craft that's on-rails (really, >2.5 km from whatever craft you're controlling) will not experience any drag, but will be removed by the game if it reaches the 0.01 atm level (~23,026 m).
  7. More realistic, yes. It's debatable as to whether it makes things harder. Mass ratios required for orbit are pushed back to where they were circa 0.15, but you need to watch your maneuvers and structures more carefully. Also, aerodynamic stability becomes much less trivial.
  8. Sort of. In principle, you could get both, but the level of precision required is impractical in KSP. And like skipping a Mun slingshot for interplanetary missions, skipping a Jool slingshot for interstellar missions costs comparatively little ÃŽâ€V. (My assumption is that you're burning >>20 km/s at periastron. Possibly hundreds or even thousands of km/s, if we assume new engines.)
  9. Chute parameters are here. It sounds like your probe is running out of electricity on the way down. What does the resource tab say? (Probes need electric power to be controllable)
  10. When they're suffering from flameouts at 1/15 or less of max-throttle. This assumes a design that can safely fly east until it's in an unstable orbit, though. (If you do this right, you need only ~30 m/s on the rockets to pull your Pe out of the atmosphere) The exact amount of intake air at flameout seems... wacky. It's higher when you have more intakes.
  11. I suppose Jool could be interesting for entering the system, but how much aerobraking would be possible/survivable? Even without reentry heat, the force differences on parts at hundreds (or thousands) of km/s would be... substantial. Yep.
  12. This poll seems b0rked. None of the prebuilt stock rockets quite correspond with any of those. Worse still, some of those missions used multiple rockets. For Mercury, do you mean Atlas or Redstone? For Apollo, do you mean Saturn Ib or Saturn V?
  13. For the purposes of starting out a journey to another star, I'd go with Dres or Eeloo (Low mass worlds somewhat far out). From there, do a stardive, with a large burn at peristron periastron for the purposes of maximizing my hyperbolic excess velocity. What to do when entering a star system seems like a rather harder problem (aerobrake? Ha!)
  14. N/A. If star systems are realistically far apart, getting to one in a useful timeframe will require a ÃŽâ€V budget that trivializes interplanetary travel. I suspect that the best place for a fueling station would be near a large resource supply (eg: Kerbin).
  15. Every time I run the numbers on SSTO and 2STO (4500 m/s) rockets, I get somewhat larger payload fractions on the LV-T30 powered ones.
  16. That only has LV-T30s on the bottom? Nothing with TVC? You're critically short on control authority once you're out of the lower atmosphere...
  17. Ah, the aerospike drag bug claims another rocket! Pbhead:The aerospike is missing the drag info in its part.cfg file. As such, it uses the default drag (0.1), which is lower than most parts use (0.2). Because it is less draggy, it wants to be at the front of an object, so rockets using aerospikes tend to be dynamically unstable. This can be fixed by either adding the drag info to the part file, or using another engine (eg: LV-T30). Rockets with enough control authority can simply brute force their way through it, FWIW.
  18. I'm not understanding the value of the poll; designing for a specific ÃŽâ€V isn't that hard.
  19. Struts, control authority, fuel drain, drag. Probably something in there.
  20. Not intentionally, but sometimes extraneous torques force it. Also, why do a 90° roll + pitch when you can yaw?
  21. Started playing with 0.8.4. Paid $7 around 0.13 or 0.14.
  22. 1) Use fewer and larger parts. This is easiest with tankage, and may give a performance improvement, given that the larger RCS tanks have better mas ratios than the smaller ones. 2) No doodads. If you're not using FAR, nosecones are worse than useless. Ditto antennas without remotetech or telemachus. Similarly, if you don't have any parts using electricity (ion engines, rover wheels, lights, scientific instruments, probe cores), there's no need for power sources. If your electrical needs don't include rover wheels or ion engines, then solar panels and batteries aren't really necessary. A single RTG will cover *everything* 3) Figure out what the minimum number of struts you need is. Struts are notable for increasingly lag. 3) You don't need very much RCS. A well designed rocket will reach LKO without using *any*. 4) Don't go overboard on stages. 2-3 is plenty to reach orbit. I'm unsure if 4 offers a significant performance advantage.
×
×
  • Create New...