Jump to content


  • Posts

  • Joined

  • Last visited

Everything posted by foamyesque

  1. I'm impressed! I didn't think the Spark could do it without staging. On the other hand, I don't like the nose-cone-clipping technique for drag reduction much. But even with that said, I believe you're the first person in five years to beat my design, so very well done.
  2. I personally think Minmus is one of the most useful bodies in the entire solar system. It's easier in many ways to get to and from than the Mun and much better suited for ISRU projects with the lower gravity (and flatter surface).
  3. Load up the torchship I used to insert into a retrograde Kerbin orbit, wait for Kerbin to rotate to the correct angle, then launch more or less straight up. When you have 22km/s of 1+g thrust you don't need precision. I might be caught by the game having to slow down during the launch sequence, though.
  4. Yeah, about the only structural failure you can reliably get any more is ripping wings off when executing 40g manouvers in the atmosphere. Nobody used to modern KSP has any idea what Wobbly Rockets(TM) used to be like. I bent some rockets into a clean horseshoe in days gone by.
  5. Jully 2011, 0.8. I had a few days of playing without symmetry and no option for snapping placement before 0.8.1 was released. Those were some wobbly-ass rockets.
  6. It's actually something I do all the time. Engine gimbals give you enormous torque compared to basically anything else, excepting reaction-wheels on small ships and appropriately sited aerodynamic control surfaces. With particularly large craft I will often crack the throttle in order to align, and then zero out the (minor) translation drift over the course of the burn. And with small craft I begrudge any pennysworth of mass not strictly dedicated to the mission :p
  7. Gimbal control is by far the most effective way to perform attitude control in a burn, excepting perhaps atmospheric control surfaces. It's non-burn attitude control that it struggles with, since any rotation inevitably requires some translation if you're using gimballing, whereas RCS can null out and reaction wheels don't produce thrust as such (although they do generate angular momentum from nowhere, which means you can build some interesting contraptions).
  8. KSP's reaction wheels are literal magic. Things like the Hubble or the ISS do use them for attitude control and fine pointing, but there's a world of difference between precisely torquing an orbital telescope to a ten-thousandth of a degree, and shoving an airplane around in midflight :p
  9. This is one of the first things I do with a new game. Makes me sometimes wish I had a third hand, though.
  10. Your issue is the addition of the radiator and the removal of the fins. Radially attached parts have significant drag (and, if asymmetric, can also cause a torque), and because you've put it at the top of your rocket, you've moved your center of aerodynamic force upwards. At the same time, you've eliminated the fins at the bottom that would've moved the center of aerodynamic forces back down. For a rocket of that size the capsule would provide entirely adequate steering otherwise. The heat shield's probably also unnecessary for an LKO machine like this appears to be, but if it's in the stack it shouldn't be causing aero issues. My suggestion would be to eliminate the radiator -- I don't see anything on the rocket that would require it -- and, if that's not enough, putting the smallest fins on the second of the solid stages. First one won't get you going fast enough for aero instability to be an issue, but the first Hammer will. Note: The above is trying to work with your extant rocket. My own preference for using solids for launchpad kick is to radially mount them and co-fire them with a gimballing liquid engine; the liquid will give you a bunch of control authority and with its likely higher efficiency is better at sustaining your flight, but the solids will shove you up to working speed much faster and cut back on your gravity losses significantly since you don't have to painfully crawl up at 1.1 TWR or what not. By the time they fall off you'll have burned enough liquid fuel, and gained thrust by getting into thinner air, that the liquid engine can now propel you just fine on its own. In addition, because they're a radial attachment at the bottom of a rocket, they can -- it depends on the weight distribution of the rest of the rocket -- act to stabilize you aerodynamically as they burn.
  11. It wasn't tied to the throttle; you can see mine is set at zero. As far as I know it was completely meaningless, and I don't remember at this remove what made it light up or not. My favourite part about picture is that you can clearly see the great big divot I had to make in order to avoid crashing into the old launch gantry
  12. Rockets flip for one of (usually) two reasons: 1. A center of mass that has moved below the center of aerodynamic pressure, causing aerodynamic instability; 2. A center of mass that has moved out of alignment with the center of thrust, which will induce a torque, and that torque becomes larger than your ability to counteract it. A picture of the rocket would be useful in figuring out the cause. It's usually aerodynamics if you're in an atmosphere, since engines are heavy and so fuel draining will tend to move the CoM down over a given stage's burn if you have them at the back (as is usual). One of the advantages of a staged design is that the mass of the next stage up helps to counteract that.
  13. I have a sneaking suspicion I've posted this before, but the definitive More Boosters picture:
  14. Nah, I've used it for orbital manouvers too. When you're that light you have all the dV in the world, if you want it. Nulling out any unwanted translation isn't difficult unless you're trying for extreme precision. This is especially so if you've got a pair of engines; you can roll trivially, toggle engines on and off with action groups, and flip end-for-end with just the barest puff of propellant and barely any translation. You should try it sometime. It's a whole new way to fly.
  15. Yup. Can, have, and might well do so again. :p I prefer to use something like RCS or torque wheels on larger craft, but on a tiny probe, you get by far the best attitude-control-for-mass from a gimballing engine. Went to orbit on 670kg that way :p
  16. The OCTO-2 specifically, as the lightest probe core and the one that you'd probably use on anything that actually would mount an Ant in the first place, does not. Nor do lawnchairs, if you're building some kind of lightweight Kerbaled craft. Those would be the very supplemental control systems I am talking about. And their mass is poison for lightweight design. The smallest reaction wheel has a mass of 0.05t and is, in addition to being way more control authority than something using an Ant could possibly need, shoots the TWR in the foot. A pair of Spiders provides twice the thrust at under two thirds the weight of an Ant + wheel combination. And doesn't need electrical power, to boot. The (slight) vacuum Isp difference is more than made up for by the weight savings on these kinds of microsats. This is even more true if you're going really lightweight and using a single Spider through the use of the translate tool.
  17. The Ant engine has no gimballing, though. It'd be wonderful otherwise, but the absolute requirement to spend additional mass on a supplemental control system means it is heavier than a Spider.
  18. I've busted a lot of wheels on Eve or trying to haul things too big for 'em. Surface docking particularly can produce unexpected forces that just pop the suckers. So can jet-assisted roving on Kerbin.
  19. Oh yeah. I built a plane I couldn't get to stop, even with a parachute, by accident. And the souposphere was improvement over what came before it, what I call in retrospect the brickosphere. At least the souposphere faded gradually as you got higher. The brickosphere was a brick wall at 35km altitude, and vacuum beyond.
  20. Heh. It's true, they are a subject of debate! On non-delta designs, where your CoP naturally tends towards the midbody, you can build a tail out and have it work fine, using a couple of all-moving pitch control surfaces, maybe some autostruts to make sure they actually move the ship instead of just the tail. Deltas, though, tend to put the CoP far to the back, and if you want a CoM that doesn't shift, it usually means it's further forward. Canards are very helpful there. Sometimes I even use both. The alterations in drag between the nose and tail can give you significant control authority even in a stall situation, allowing you to force the nose down to get out of the stall, and reducing the strain on any supplemental control systems (RCS, wheels).
  21. I know for a fact this doesn't happen in stock. I lock or limit engine gimballing frequently and almost always fly with SAS on in some fashion, and I've never, ever, seen those gimbals move where they shouldn't. I would put money that the culprit is a mod you have.
  22. I'm pretty sure stock aero models a drag shift, yeah. It definitely models a drag spike through the supersonic region. I've had spaceplanes that have been completely uncontrollable through 90% of their entry suddenly flatten out and fly smooth as silk once I drop out of high transsonic, then turn to lawndarts in the subsonic area. If your plane is tumbling on re-entry you have a CoP/CoM inversion, there's no question there, but the cause can sometimes be tricky to diagnose. KSP stock aero does model stalls these days; if you turn on the aero overlay and generate enough angle, you will see the blue arrows from your wings disappear and red arrows spawn. If *some* of your surfaces are stalled out, and others not, your CoP can move around significantly, a situation that not only is very likely to occur in a tumble, it can make the tumble worse. In addition, stalled out control surfaces are dramatically less effective at actually steering your ship; you can pilot a nearly-unstable craft reasonably easily if you have good control authority, but if it jams up on you things will rapidly go downhill. As a general preference -- and particularly when working with a delta design as yours is -- I tend to use canards over tail-mounted elevators. It makes it easier to get a CoP nicely centered (which in turn makes centering the CoM on it easier), and they behave better in high-angle flight. It is also generally a good idea for anything going supersonic to use all-moving control surfaces, as real supersonic planes tend to.
  23. The most useless thing in KSP history was the old launch gantry :p
  • Create New...