Jump to content

ferram4

Members
 View Profile  See their activity

  • Posts

    3,132

  • Joined

  • Last visited

 Content Type 

Everything posted by ferram4

  1. ferram4
    @a1270: That would be because the projected area is marked "private" in the current version. I've switched over to a public projected area instead (labelled "S") in my version to fix that. Should be in the next version. @BrickedKeyboard: You would need to put the center of lift right on the center of mass to make that work without control surfaces; that would allow the small gimbal range of the jet engines to control the vehicle. Keep in mind that it probably won't be flyable at supersonic speeds though. Other than that, you need to shift your main gear forward or it's not going to pitch up and take off on the runway. The original complaint of flipping up like crazy as soon as it takes off sounds like it's unstable, which means you need to move the center of lift further back. The best FAR tutorial is to look up aerodynamic theory in real life; where do you think all these principles come from? @Camacha: Yup, wing sweep is accounted for.
  2. ferram4
    That would be a relatively light vehicle (remember, it is empty) producing quite a bit of body lift due to its angle of attack. Yes, things other than wings can produce lift.
  3. ferram4
    @KerbMav: The drag value of the nacelles is an issue whether FAR is installed or not; FAR doesn't change the stock intake behavior, and that's the source of the error. The reason Taverius' pack overrides FAR's jet thrust values is because my values are a modification of the stock behavior so that it is slightly realistic, but can still be used for the same purposes, but his values are more grounded in real-life jet performance. @XNerd_Bomber: Possible reasons: Your "gravity turn" is not an actual gravity turn but is instead an overly aggressive pitch-over maneuver that causes the rocket to move out of it's stable regime. Your rocket has a very light, but large payload at the top; this makes the rocket less stable. Your rocket's fuel drains in such a way that it becomes less stable as fuel is drained. You need more fins at the back of your rocket. Your rocket is not designed to be an aerodynamic shape, but instead is designed with traditional Kerbal engineering in mind, which ignores aerodynamics in favor of dV and TWR. Take inspiration from real-life crafts. A picture would really be quite helpful. @LoSboccacc: You probably need more struts to keep it from flexing. That is probably the cause of the issue. @jpinard: I have no idea; probably whenever I finally get the lift of reentering capsules right. Odds are airplane physics will not largely be affected by any changes, so don't worry too much.
  4. ferram4
    Part of the problem is that FAR doesn't currently model the lifting effect from heat shields properly; when it does, that should help add some stability to those vehicles, but I've had some trouble implementing it properly and working nicely with other aerodynamic properties. Another problem is that your reentry vehicle shouldn't be taller than it is wide; when it is, that leads to the CoM being way to far back, no matter what configuration you manage to come up with.
  5. ferram4
    @KerbMav: FAR makes a tank more aerodynamic when it has a nosecone by adding extra drag to unused attach nodes when there is no part attached there. Also, congratulations on building a lifting body; at ~2km/s pretty much anything will make significant lift (also, keep in mind that part of that lift effect is not actually lift, but the fact that you're very close to orbital velocities). At that speed, you only need to make about 1/10 the craft's weight in lift to keep it in the air. @HogDriver: Aware of that, it is fixed in my build and should be fixed in the next release.
  6. ferram4
    @Galane: That's probably due to the fact that physics are technically turned off for the small cubic struts. I don't know how that factors into how things work out, but it does mean that using them to do anything physics-based will most likely cause problems. @Surefoot: Playing with the non-drive settings generally results in nothing good, as far as I can tell. The drive settings tend to be better at controlling the behavior of the joint. Yes, the toroidal fuel tanks are still squishy; they weight practically nothing and are rather small, so they shouldn't take that much in the way of force in any realistic situation. Further testing indicates that setting "AngBounce = 1" seems to fix the surface attach joints, but causes the off-center-under-load stack attach joints to reappear. So I'll change some code to allow separate tuning of the different attach joints and we'll see what happens.
  7. ferram4
    Having gotten KSPX, I could not reproduce the issue. Every launch I did of the booster resulted in a successful launch and no sticking to the pad. Download 1.3 again, reinstall it and see if the issue still occurs. If it doesn't, I suspect some other mod is causing an issue, possibly involving an exception being thrown initializing physics on a part. From what I can see, KJR isn't causing this.
  8. ferram4
    Yeah, after the boosters come off it's got a very lackluster TWR. Pitch over later and only start to switch from surface prograde to orbit prograde at ~1.6 km/s or so.
  9. ferram4
    @Dragon01: I just ran a launch with these figures for it: Boosters: Dry mass: 3.78 tonnes Full mass: 44.5 tonnes Liquid Fuel: 3528 Oxidizer: 4312 Thrust: 991 kN Isp vac: 310s Isp atm: 245s Core: Dry mass: 6.9 tonnes Full mass: 105.4 tonnes Liquid Fuel: 8586 Oxidizer: 10494 Thrust: 997 kN Isp vac: 311s Isp atm: 264s Upper stage: Dry mass: 2.35 tonnes Full mass: 22.9 tonnes Liquid Fuel: 2061 Oxidizer: 2519 Thrust: 298 kN Isp vac: 330s Isp atm: 280s Everything else the same. The Soyuz craft was released at 300 km and 7.5 km/s; I believe the difference can be made up with my poor piloting, which meant that the upper stage spent some time burning at 45 degrees above prograde to keep the rocket at apoapsis. Is it possible that your numbers might be wrong somewhere? @ZRM: I hope that density and pressure curves can be specified separately; density should still follow a simple exponential curve. If that isn't the case, then FAR might do weird things, since density is more important for aerodynamic considerations than absolute pressure is.
  10. ferram4
    @Dragon01: I'm investigating. Hopefully it's something easy to fix. @praise the suuun: Vertical stabilizers do very little to affect pitch stability or to affect where the center of mass is; the only have significant effects on yaw stability. Horizontal stabilizers do help affect pitch stability by creating lift behind the center of mass, helping to tilt the plane into the airflow properly. Yes, it is possible to attach engines to the tops of vertical tails with this (it always was possible, even in stock KSP) but the pitch-down moment you'll get from that under thrust will probably be highly undesirable.
  11. ferram4
    Are you absolutely certain that it has a high enough TWR and enough dV? Unless you've made changes to the Bobcat Soyuz rocket, it only has 6 km/s dV, which means that it will always fall short of orbit. Drag losses will be higher with the fairing not working, but it won't be significant enough to prevent you from reaching orbit unless you're always a 100 - 200 m/s short; total drag losses shouldn't increase significantly above 200 m/s with the fairing not working, but the stability of the vehicle should become a lot worse.
  12. ferram4
    Ah, I see you changed the values for the angular limit. Set them back to zero and it won't to stuff like that anymore. Actually, just don't change any of the angular limit values. Only mess with the linear and angular "drive" values. I saw that same thing happen to many, many rockets. An alternative solution is to play with the angular drive settings and see if you can bring it back to an upright launcher. There is a damping value added in there that is removing energy from the system, but it's part of the problem with numerical simulations having to run things in discrete time; all motions will be less stable when run with discrete timesteps than if they were run with continuous time. Unfortunately, for that situation the timestep was large enough to make that thing unstable. So yeah, it is a limitation of the technology, and there's really no way around it, besides shorter timesteps and more lag (or more joints; try rebuilding your vehicle and connect the girders to each other with struts and see what happens).
  13. ferram4
    @Galane: That rocket has more non-stock parts than just Restock. Some kind of SAS module keeps me from loading it. To check the issue. You are running version 1.3 though, right? @Surefoot: Yeah. I've confirmed that. I think it's a result of a very large mass on the other end of that pendulum and the way that the springs reinforce each other; you've got ~42 tonnes on the end of a radial connection, and the struts that you added aren't set up to really reinforce things. The issue can be temporarily solved with struts connecting the pods to each other rather than relying solely on the central section. I'll look into what I can do to fix it.
  14. ferram4
    Well, what does your design look like? Which connection is the actual problem connection? How many physics-less parts are involved in this mess? Try boosting the damping values in the config.xml and see if that helps with the issue.
  15. ferram4
    @mwlue: I'd take Jack Wolfe's solution for the NP LES; there's no reason that it should be that overpowered. KJR also doesn't do anything to mess with gravity or aerodynamics. Perhaps you have installed another mod that is changing the way physics behave / your rockets behave.
  16. ferram4
    You're using an old version then; that would probably be version 1.1. Get 1.3 and the problem should disappear. Yes, there have been a lot of updates to this over the few days it's been out. Lots of really terrible bugs appeared that couldn't justify putting off a solution.
  17. ferram4
    You assume wrong. KW fairings pop off perfectly fine.
  18. ferram4
    What's happening is that when the engines are tilted like that at zero angle of attack they are producing 1) more drag, due to their angle, 2) negative lift, due to the same thing and 3) a pitch up moment at that lower angle of attack due to the negative lift. At a higher angle of attack they result in, overall, less lift, a more positive pitch moment, but less drag due to their lower angle with respect to the flow.
  19. ferram4
    Alright, version 1.3 is out, which fixes the horrible launch clamp bug and implements a bunch of changes by a.g. that make updates occur properly on docking and better approximations of joint forces. There's also a cutoff for masses below which joint stiffening isn't implemented; this can be changed in the config file. Hopefully there aren't any other problems. @iornfence: So you're saying that you brought a vessel with solar panels deployed from space down to the surface of a planet without the panels breaking. That sounds like a problem with something else, since solar panels breaking off is supposed to be handled by the stock solar panel PartModule; unless you can provide an output_log.txt that can trace the error back to KJR, I'm going to guess it's another mod causing that. There was a decoupler issue in v1.1; are you sure that you're using the most recent version of the mod? If you're using v1.3, would you be kind enough to provide an example craft so that I can debug it? @Traches: Meh, I'm used to it. Nobody calls support to tell them they're perfectly fine.
  20. ferram4
    You tried to activate the control systems using the buttons on the bottom of the main Flight GUI and it didn't work? Did you leave SAS on? It might interfere with the FAR control systems. Are you using any other mods that might conflict with this?
  21. ferram4
    Perhaps it's a memory issue. Install the lower texture packs and see if that helps; if it does, then you know that's the issue. If it doesn't, then you'll have to post an output_log.txt so that we can look at it and see if that helps find a problem. Honestly, this mod doesn't do anything in the VAB, so if it crashes when you switch to that it's probably not KJR.
  22. ferram4
    Does removing KJR fix it? That mod can (apparently) cause very weird issues with very light parts.
  23. ferram4
    @asmi: I've been trying out a similar system that would work for any vessel that loads, whether it's on the pad or it is landed and comes into physics range. So far nothing good has come of it, but I'm hopeful. If necessary I'll implement a similar system that scales up the Launch Clamp stiffness before adding gravity. I'll also have to figure out how to lock user control prior to all of this being completed. @a.g.: I think I'm just gonna add a check to ignore parts below a certain mass. Make it high enough that probe parts shouldn't be affected, but silly things like that will be. @Starwaster: If the clamps are too rigid, the forces applied to the rocket cause parts to break off / explode. If the clamps are too springy, the rocket falls to the pad or the extra fall distance results in the rocket bouncing around more, which can break things off.
  24. ferram4
    @NathanKell: Well, there are three main reasons: For the most part it doesn't seem to be necessary; there are only a few odd exceptions that seem to be mostly due to the behavior of mod parts, and I don't expect mods to mesh perfectly together. I'm not exactly sure what breakForce is measured against. I think that it is the force applied by the joint outside of the "Drive" parameters I use to really keep the stiffness in line, but I'm not too sure about that. What happens when something I didn't anticipate comes along and it is either too strong or breaks when you sneeze on it? Besides, further thinking makes me think that the actual issue with the parachute was the "crashTolerance" value being exceeded, since that seems to control whether something blows up or not (or is it the "strength" value... I'm honestly not sure. I'll have to look into that). Another possibility is that the workaround I did for the decoupler-no-ejection-force bug is causing the issue; that's been removed and replaced with a solution by a.g. that allows me to get away with not having to do that, so I can test in my build and see if anything happens.
  25. ferram4
    Then you need to increase the breakForce and breakTorque parameters for it in its config file. I can look into seeing if there is a way to scale down the stiffness to not break very low-mass parts, but that raises the question of what should qualify as "low-mass" and thus have low stiffness parameters applied to it.
×
×
  • Create New...