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About Stratzenblitz75

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    Planetary Tourist

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  1. What did you do in KSP today?

    Today, I built a big rocket...
  2. 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.
  3. 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.
  4. 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!
  5. What did you do in KSP today?

    Today, I celebrated Christmas... On Laythe:
  6. 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:
  7. What did you do in KSP today?

    Today, I went to Duna and back... Using only electric power and xenon:
  8. What did you do in KSP today?

    Today, I sent a rocket to the seafloor of every ocean.
  9. 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?
  10. 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!
  11. 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
  12. What did you do in KSP today?

    Today, I went fast. Faster than I've ever gone before:
  13. 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.
  14. S75's Video Collection

    10,000 subs! You know what that means; time for another sub special!
  15. What did you do in KSP today?

    Today, I sent a station to Eeloo: