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tavert

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Everything posted by tavert

  1. Cool idea exm. I personally manage my crafts with a naming convention (start at 1a, bump the number for a major redesign, bump the letter for minor tweaks) but the end result is my craft folders are pretty cluttered. You should absolutely apply the versioning to quicksaves and persistence files too!
  2. A nitpick: the scale height of Earth's atmosphere is a bit higher than Kerbin's, and the sea level pressures are the same. Earth's atmosphere doesn't behave isothermally or have a hard cutoff at 1e-6 atm, but that doesn't make Kerbin's atmosphere thicker. It's the force of drag that is much higher in stock KSP than in reality, for aerodynamically shaped objects.
  3. Europa scientific lander. Automated Mars ISRU demonstration payloads. Deep space habitat, for Lagrange point and/or asteroid missions.
  4. Part of the reason for turning immediately is so if something bad does happen, you don't destroy your launchpad infrastructure with falling debris.
  5. Oh. Hah, there you go then, that makes sense. Didn't look at the numbers carefully enough to see that.
  6. That's highly unlikely. The stock game won't adjust your throttle setting unless you tell it to via shift, ctrl, or x.
  7. Volume is one way to measure a quantity of a liquid, but mass is more useful in most contexts (particularly for stock KSP where we don't really have to worry about tank construction or different-density fuel types). In common usage mass and volume can be used roughly interchangeably since most liquids we commonly deal with are approximately incompressible across the temperature and pressure ranges we normally encounter. The resource quantities are also not just liquids - electric charge certainly isn't in units of liters (or any other volume unit) and never has been, the liters tooltips were removed before electric charge was implemented as a resource.
  8. You guys appear to have missed my point about densities. There's no point in trying to apply real-life fuel densities and calculating internal volumes when we're taking off from a planet that is several times denser than any known element. If you're using realism mods then it matters, but not in the stock game. I agree with Kasuha that the volume unit is irrelevant, if the resource units are even supposed to be measuring volume. It's quite arbitrary, but calling them liters and assuming resource units are in terms of volume is for the most part inherited from older versions of the game.
  9. In Kasuha's particular case, his rocket was at full throttle for almost the entire flight, his TWR was low so he needed extra hang time to reach orbital speed. It's interesting that the result you're showing achieves some of that hang time by overshooting the apoapsis, instead of relying on higher angle of attack and a slower but monotonic climb (which would've been my intuition-based guess as to the best trajectory in this situation). I'd have to find in the code exactly where you're using the specific impulse data, but judging by that input table it looks like you might get slightly incorrect behavior at atmospheric pressure between 0 and 1. Let's take an example of 2 engines, with thrust1, ispvac1, ispatm1, and thrust2, ispvac2, ispatm2. isp1 = ispvac1 + p*(ispatm1 - ispvac1) isp2 = ispvac2 + p*(ispatm2 - ispvac2) isp_combined = (thrust1 + thrust2) / (thrust1/isp1 + thrust2/isp2) This is not the same as taking ispvac_combined + p*(ispatm_combined - ispvac_combined), except at p = 0 or p = 1. So you can't enter things just in terms of combined Isp at vacuum and atmospheric conditions, you need the thrust and Isp curve of each engine type. And if you're inputting thrusts as kN, may as well input stage and fuel masses in tonnes, for consistency with every other mass measurement in KSP.
  10. Could be liters. Used to be explicitly labeled as liters. Leads to some unrealistic densities, but so does everything else in KSP.
  11. But hey, its engines live on, propelling Cygnus to the ISS in 2014. These engines are half as old as "liquid fuel rocket engine" being a thing, and they're still useful!
  12. Up to 0.22, if an engine was deprived of one but not all of the resources it required (which you could always do manually by disabling flow of that resource from all sources), it would continue to drain the remaining resource types while throttled up. The behavior changed in 0.23 along with the introduction of tweakables (or maybe unrelated?). I don't think there's a stock way to do this right now, you either need a mod, or dock with something that has extra space, or rely entirely on setting your tweakables exactly right before you even launch. Would be nice to get in-flight fuel/oxidizer dumping capability back in stock somehow.
  13. If you had perfectly lossless electronics, bearings, and no air friction, you could maybe put something together that would sustain any initial motion (which would need to be initiated by an external input of energy) indefinitely. Otherwise, no.
  14. This was several versions ago, 1.26 units of oxidizer unmanned SSTO: Or sort-of manned, 0.12 units of oxidizer (full album at http://imgur.com/a/2DAhq - note I had to drain oxidizer from the jet stage on the launch pad, which these days you'd do with tweakables):
  15. Looking better. You can probably get away with only 1 or 2 engines on your lander, you don't need much TWR for the Mun. If you're already building asparagus, try to use as many of your engines as possible at all times. An engine that isn't burning is dead weight and hurts your delta-V (unless it's got lower Isp than the engines that are currently burning, then it just hurts TWR). If you're using SRB's, a neat trick is to put a few fuel tanks on top of the SRB's, with fuel lines feeding your core stages. If you set it up with slightly less than the SRB's burn time worth of fuel for your inner liquid engines, then you'll drop some tank mass along with the empty SRB's.
  16. Do you want to build it yourself, or buy from a manufacturer? Does $1k include peripherals like keyboard/display/mouse, or not?
  17. In the stock tech tree the LV-909 is at Survivability, the same tech as the basic medium-sized landing legs. Unless you're unlocking techs one component at a time, you probably do have the LV-909. You might need to scroll the propulsion page to see it? On the subject of landing legs, 12 is probably overkill. You rarely need more than 4.
  18. No problem. You probably read the Wikipedia article on the rocket equation and saw that the common derivation method is to note that force is the time derivative of momentum (= m v), but since both mass and velocity change with a rocket, you get both mdot and vdot terms. Your way works fine here though. For derivation of Kepler orbits, are you able to follow either of the derivations here: http://en.wikipedia.org/wiki/Kepler_orbit#Mathematical_solution_of_the_differential_equation_.281.29_above ? You need to do a few not-immediately-obvious variable substitutions and apply conservation of angular momentum to get the central body inverse square force problem into an easy to solve form.
  19. Don't use the Mark 55, it's pretty lousy. For early-tree rockets, you should use the LV-T30 when you need TWR (replace a couple of them with T45's if you need more control), and LV-909 when you don't. You also don't need RCS if you aren't docking. I remove the monopropellant from the capsules pretty much every time for a little extra dV.
  20. Ooh, sounds interesting, what for? RCS balancing? Something related to fuel flow? Estimating costs for contracts?
  21. Your integral has the wrong sign. The indefinite integral of f/(m0-mr*t) with respect to t is (-f/mr)*ln(m0-mr*t). You want the definite integral from t1 to t2, which equals (-f/mr)*ln(m0-mr*t2) + (f/mr)*ln(m0-mr*t1) = (f/mr)*ln((m0-mr*t1)/(m0-mr*t2)) = (f/mr)*ln(m1/m2).
  22. None of the rover wheels are going to stay intact up to takeoff speeds on anything heavy. Aircraft landing gear are it for high speeds, as far as stock parts go.
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