Stratzenblitz75

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Everything posted by Stratzenblitz75

  1. Stratzenblitz75

    What did you do in KSP today?

    Today, I went to Gilly:
  2. Well, its been a long time since I did a Jool-5 mission, so I figured now would be as good of a time as ever to revisit it. Here's a fully reusable, low-mass take on the challenge (without using jets, NERVAs or Ions). Of course, resource tab and KER are open throughout all important burns and maneuvers. Let me know if you'd like me to provide anything else. Thanks!
  3. Stratzenblitz75

    What did you do in KSP today?

    Today, I went to Jool:
  4. Stratzenblitz75

    What did you do in KSP today?

    Today, I went to Mars:
  5. Stratzenblitz75

    High speed stock Aircraft challenge.

    Here's 2.032 km/s <1 Km. The real trick to doing this is a fairing + sideways heatsheild. I didn't optimize this very much so someone could probably take the same principle and make faster one. And yes, it does fly at lower speeds and can be landed without a parachute (although, with much difficulty).
  6. Stratzenblitz75

    What did you do in KSP today?

    Today, I built a communications network... With math!
  7. Stratzenblitz75

    What did you do in KSP today?

    Today, I built a big rocket...
  8. Stratzenblitz75

    Reusable Staging Off Eve

    Indeed, having a TWR <1 on Eve is a bad idea. You really need to be ascending as quickly as possible to start out. However, my point with a horizontal take off isn't to try gradually climbing to orbit, but instead, is a different way of getting the vehicle vertical. After a horizontal take-off, you can quite easily leverage the engine gimbals + lift to point yourself upwards. You could even use the upward slope of a hill to help out too. Of course, as you said, during this initial pull up maneuver, you aren't making any progress, but the horizontal take off isn't as bad as it seems. Also, yeah the suborbital hang-time is a problem for the second stage. To get around this, I think you could build the first stage so that it is almost an SSTO (maybe 500-1000 m/s of orbit). From here, you should be able to get the second stage into orbit before leaving KSP's 40 Km unload range.
  9. Stratzenblitz75

    Reusable Staging Off Eve

    I haven't tested this, but my first thought for reusable Eve infrastructure is to have a ISRU equipped rocket spaceplane with a detachable, winged second stage. The first stage of the rocket plane would take off horizontally and then climb into a suborbital trajectory where it would deploy the second stage. The second stage would reach orbit, while the first stage would glide back down to a flat, high altitude landing site (>5000 m). From here the first stage could use ISRU to refuel, and the second stage could deorbit and glide back down to this landing site. Since they are both horizontal when landed, they can be redocked and the arrangement can take off again without too much trouble. Alternatively, you can setup a ring of high altitude ISRU bases around the planet for the plane to land at. This would require more setup, but would enable better payload fractions. While this may work on Kerbin, it probably won't work as well on Eve. This is because Eve's oceans are much denser than Kerbin's: An ore tank on Kerbin will sink just fine, but will barely sink on Eve. If you want ballast for Eve, you pretty much need to use Vectors, or the I-beams to be effective. And even then, you need a surprising amount to get something to sink, much less sit upright in the water. Not to discourage you from this approach, just be sure to do your testing on Eve first because their oceans are quite different.
  10. Stratzenblitz75

    Reaction Wheel Kinetic Launchers

    You can actually get quite a boost from a centripetal launcher... Given that your reaction time is fast enough and your launcher can keep itself from tearing apart. As mentioned by EpicSpaceTroll, tangential velocity is calculated from ω*r, where ω is the angular velocity and r is the radius. However, there is another factor to consider; centripetal acceleration, which is calculated from ω2*r. As you can see for a fixed radius, tangential velocity depends depends on ω, while tangential acceleration depends on ω2. This means that as you double your tangential velocity, your centripetal acceleration will quadruple. So, what does this mean for KSP? Lets look at an example. Lets say you want to build a centripetal launcher to put launch an object from the surface of minmus into orbit. Lets say you choose your launcher to have a radius of 10 meters. Since minmus orbital velocity is ~160 m/s, you would have to achieve an angular velocity of 16 rad/s (150 RPM). This would induce an acceleration of 2560 m/s2 or 261 Gs. Okay, this is probably not viable. Even ignoring the G force, the high rotation rate would make it very difficult to time the release. Lets shoot for a more reasonable rotation rate then. Say we want 2 rad/s. In this case, we would need a radius of 80 meters. A launcher of this size would induce 320 m/s2 or 32 Gs of acceleration. Something like this is totally within the bounds of human reaction time, and KSP's auto-strut strength. However, with a radius this large, the launcher's moment of inertia becomes very large as well. Even if you use a lot of reaction wheels, you'll be waiting a long time for this thing to get up to speed. Another electric power source you can use are wheels. If you are launching from the minmus flats, you can feasibly use wheel power. The bugged differential steering on the large rover wheels could be the perfect power source. While a cool idea, for most cases a centripetal launcher is likely not a good option. Rocket engines are far less complicated and are much lighter. That said, screw practically! Centripetal launchers are a fun engineering challenge to build and are an excellent physics demonstration. I encourage anyone who is interested to give it a try!
  11. Stratzenblitz75

    What did you do in KSP today?

    Today, I celebrated Christmas... On Laythe:
  12. Stratzenblitz75

    Do something nobody has done before

    This may not be a first in KSP, but I'm fairly certain its a first since the aerodynamics changed in KSP 1.0: Duna and back on electric power and xenon:
  13. Stratzenblitz75

    What did you do in KSP today?

    Today, I went to Duna and back... Using only electric power and xenon:
  14. Greetings! If you’ve ever tried to build a landspeeder and tried to set a landspeed record at Kerbin’s poles, you may have run across a strange bug. For whatever reason, you simply cannot get your craft to go above a certain velocity. It just sinks into the ground and explodes as if the terrain colliders simply ceased to exist. Even stranger, it appears that the speed at which the bug occurs is related to the acceleration of the craft. The land speeder above can reach 1808 m/s at full throttle, but at 50% thrust limiter, it fails at ~1600 m/s. So what is going on here? Curious, I devised an experiment to see if there was some sort of predictable relationship between acceleration, final speed, and distance traveled. Here is what I came up with: Hyper edit THIS CRAFT (which for the purposes of this report, we will call “Craft 1”) to 40 W and 80 N (These coordinates do not have a special purpose; they simply give plenty of room on the north pole to perform the experiment) Remove Atmosphere with hyper-edit Enable infinite fuel (For constant acceleration) Detach Beacon Quicksave Quickload Set Thrust Limiter to 100 Engage full throttle and ignite engine Pause the moment the camera clips through the surface (You can rapidly pause-unpause the game to do this. I found that this does not affect the speed at which the bug occurs) Record velocity and distance from beacon in a table Repeat steps 7 through 12, decreasing the thrust limiter by 5 each time (thrust limiter = [95, 90, 85, etc.]) Calculate the acceleration for each entry using the thrust and mass of the craft Calculate the time elapsed for each entry using the distance traveled and acceleration Here are the results of my experiment: Very interesting. It appears that the speed at which the bug occurs IS affected by acceleration. In fact, looking at the graph of distance vs. time, we get something that looks strikingly linear. If we take the equation of the trend line of that graph, y = 683.83x + 4367.8 solve these kinematic distance equations for the final velocity, d = (1/2)*(vi + vf)*(t) d = 683.83t + 4367.8 (1/2)*(0 + vf)*(t) = 683.83t + 4367.8 vf = (1367.66t + 8735.6)/(t) and take the limit as ‘t’ approaches infinity, lim t->INF (1367.66t + 8735.6)/(t) = 1367.66 we get a speed of 1368 m/s. This suggests that a craft traveling at a constant velocity above 1368 m/s will encounter the bug, while a craft below this speed will not. To test this prediction, I simply took the previous craft and accelerated it up to speeds ranging from 1350 to 1400 m/s. Then, I checked if the craft encountered the bug or not. Here are my results: Speed Bug? (T/F) 1350 F 1360 F 1376 F 1380 F 1381 F 1382 T 1385 T 1390 T 1400 T This data shows that my estimate of 1368 m/s is very close to the actual value. The real limit appears to be 1381 m/s. Below this speed, it does not encounter the bug at all. Once a higher speed is reached, it encounters the bug within 5 seconds, but not immediately. So, once a craft reaches a speed above 1381 m/s and remains at that speed for a certain amount of time, terrain colliders cease to exist. For curiosity’s sake, is it possible to go past this speed, and then slow down and have the colliders come back? To test this, I built this thing and set it off. And there you have it. Once the craft slows down to 1380.8 m/s, the terrain colliders instantly come back and shred it to pieces. What happens if we vary the frame-rate? Do we still get the same results? To test this, I built a new craft, which we will call “Craft 2,” with rings of inward facing seperatrons. When firing, they tank my framerate to 10 FPS. Then, I repeated the above procedure with and without firing the seperatrons. Here are the results. From this, it appears framerate does not have an effect on the final velocity of the craft. Note the differences between Craft 1 and Craft 2 are likely due to the fact that I launched them at different headings (270 and 120 degrees respectively). More on that later. Alright, so it appears that something is going on at 1381 m/s, but what exactly? The game doesn’t instantly stop reading collisions after this speed, since a speeder can go much faster. What if the game loads a “radius” of terrain colliders around the craft, and after 1381 m/s, the game stops loading new colliders? This would explain why a craft at a constant velocity encounters the bug 5 or so seconds after reaching 1381 m/s, rather than immediately. Using this kinematic equation, we can find the distance traveled by the craft from 1381 m/s to the speed at which the bug occurs. From these distances, we will be able to calculate the radius of the terrain colliders. Here are the results from applying this calculation to all of our data entries: So the data seems to be scattered around ~7.4 km, with the variation from the lowest and highest value being about 2.5 km. Since all the distances are similar, despite the acceleration, it seems that KSP does STOP loading new colliders after 1381 m/s completely, leaving just a 7.4 km radius of colliders left to travel on. But why does it vary by 2.5 km? This could make sense if we consider that KSP does not load terrain continuously, but rather, loads it in chunks. Would this explain the variation? In an ideal KSP, the distance from the craft to the boundary of the terrain colliders should be constant. However, KSP likely does NOT load terrain continuously like that. Rather, it loads it in square chunks. In such a system the distance from the craft to the boundary can vary depending on direction and distance traveled. If this assumption is correct, then it should be possible to map out one of these terrain chunks by slightly changing the angle at which the craft is launched at and measuring the final distance. So, I did just that. First, I tested headings from 80 degrees to 100 degrees in increments of 2. Then, I converted the results from polar to Cartesian coordinates. Here are my results: Hmmm, it looks like a corner of a square. In fact, if you multiply the slopes of the trend lines, you get a value very close to -1, which shows that the edges are perpendicular. 1.183*(-0.8245) = -0.9753835 So indeed, KSP does load terrain in square chunks. Alright, now let’s take ALL the data gathered from this experiment, and apply the kinematic equations from above. Here is a plot of that operation. In conclusion, this study shows that KSP loads terrain colliders in squares, and completely stops loading new colliders after reaching 1381 m/s. Effectively, this means that once a land-speeder passes 1381 m/s, it only has between 6 km and 9 km (depending on the direction and distance traveled) to hit the land-speed record before falling off the remaining colliders. But, why does the game stop loading new colliders after 1381 m/s? My theory is that the devs coded a limit into how fast the terrain loaded in an attempt to optimize the game. After all, why load terrain colliders past this speed if a collision at these speeds would almost always guarantee death anyways? If any KSP devs would like to comment on this, it would be greatly appreciated! Comments? I’d love to hear your thoughts on this as well. Also, feel free to download my test craft and perform my experiments. I have not tested this on other computers, so I’m curious if that would make a difference. Just be sure to conduct them on a STOCK INSTALL with only hyperedit and KER. This is because I've found that some mods such as kopernicus change the way the terrain colliders are loaded. Bye everyone! -Stratzenblitz
  15. Stratzenblitz75

    What did you do in KSP today?

    Today, I sent a rocket to the seafloor of every ocean.
  16. Alright, after reviewing your design, I see some areas where you can make improvements. For your first stage, it doesn't look like you have enough wheels. Evenly supporting your craft is very important for stability, so try to distribute your wheels evenly to balance the mass of your speeder. In the case of your first stage, add some more wheels to the back to support the mass of those three vectors. Also, you'll need some fins on your first stage to keep your craft going straight. This is because the ablative fairing at the front creates a lot of drag and will tend to cause the craft to flip. This true of all of your stages. These two adjustments should get rid of the side-to-side wobbling you see at the start. Also, giving your vectors more gimbal can help with stability. That said, right now, your final stage needs the most work. First, I suggest you opt for using 3 or 4 wheels instead of 2. You can get 2 or even 1 wheeled designs to work, but they take far more effort to balance properly. Having at least 3 wheels will ensure your craft's stability without sinking a ton of time into balancing its aerodynamics. Additionally, you need a tail to keep your final stage going straight. Once again, this is because of the drag the front fairing produces. I'd suggest using a rearward facing fairing plus some control surfaces to keep it pointed straight. If you want to use seperatrons for the final stage, you need to clip them into a fairing or otherwise they produce an insane amount of drag. My favorite way of doing this is to angle them by 15 degrees, and attach them to an octagonal strut to create a ring of outward angled seperatrons. You can then place this assembly inside a fairing so that just their nozzles poke out. This system is especially useful because you can simply add more rings if you need more thrust. If you want to avoid clipping of any kind, then don't bother with seperatrons; use only vectors because they have the best combination of low-profile and high thrust. One more thing for your final stage; make sure the flap you have mounted to the bottom is deployed upward slightly, but not too much. At high speeds, you will need a down force to keep your craft on the ground. If its too low, your craft will easily bounce off the ground. If its too high, your craft will be smashed into the surface. It is a fine balance so you'll have to do several runs to find the right angle of deployment. In general, make the "show aerodynamic forces" option your best friend. This handy stock feature allows you to see what parts are creating drag and lift, and how much. I found it invaluable for locating high drag parts, and either replacing them or adding fins to counteract their drag.You can enable it with F12, or through the debug menu. Hope this helps! BTW, what was the highest velocity you achieved with your design?
  17. There's two main techniques I use to make my craft more stable. For one, reduce the friction control on the wheels. In KSP, the friction control is wholly incapable of handling high-speeds so you need to set it to as low a value you find tolerable. For all of my runs, I had the wheel friction control set to 0 so that it wouldn't interfere with the performance of the craft. Of course, without friction control, your wheels don't get any grip so you have to raise it again when going slow. The other technique is downforce. When going fast, you will need some force to keep you pressed against the ground so that your car doesn't become an airplane. For this, I find flaps very effective because you can fine tune their deployment angle. If you're willing to share craft pics, I can give you more specific advice. Hope this helps!
  18. Hey everyone! I want to thank you all for giving your inputs in this thread. I've certainly learned a lot from the information you've brought to the table, and the ideas you have given me. It is because of your inputs (@suicidejunkie 's suggestion in particular) that I've managed to break escape velocity with a stock land-speeder: You made this video possible! -Stratzenblitz75
  19. Stratzenblitz75

    What did you do in KSP today?

    Today, I went fast. Faster than I've ever gone before:
  20. Yes I did. Turns out, the physics delta makes no difference to the max speed. The only time it does make a difference is when the FPS is very low (10 ~fps), and the physics delta is high (0.12). In this case, you will experience the bug much sooner. I believe there is some collider below the surface that instantly destroys anything that touches it. That said, I've managed to get around it sometimes. On a few runs, I've had the craft fall through this collider into the ocean. Its very inconsistent though. I don't think this is possible. In stock KSP you can't switch vessels while "moving over the surface". So, I just got around to testing this and YES. A lower terrain quality does increase the maximum speed reached significantly. With this knowledge, it should now be possible to break escape velocity over the surface.
  21. Stratzenblitz75

    S75's Video Collection

    Greetings! As part of my new-year's resolution, I wanted to get more serious about my Youtube channel. Before, I was very sporadic in my uploads: My Jool-5 mission video was released on June 7th, 2015 and my next video was released on Jan 1st, 2016! Its not like I was working on a video for 6 months either, I was just lazy. Now, I've become more settled with my video-editor and recording software and thus, I want to start releasing one video every month. To start the year off, I decided to go to Eve, but with a twist...
  22. Stratzenblitz75

    S75's Video Collection

    10,000 subs! You know what that means; time for another sub special!
  23. Stratzenblitz75

    What did you do in KSP today?

    Today, I sent a station to Eeloo:
  24. Stratzenblitz75

    Master Engineer Challenge (Sanic Challenge)

    Here's a land speed record for ya: 2490.3 m/s. Completely stock.
  25. Stratzenblitz75

    What is the strangest bug you have found?

    Over my time of playing KSP, I've had my fair share of bugs. But none of them come close to a bug I encountered on one of my Laythe missions. I honestly have no words...