Search the Community

As the title implies, your goal is to land on the roof of the KSC, however, this is not your every day land on the roof challenge: Tight engineering restrictions make this a true challenge, one for the can-do-all types. You have to be good not only at engineering an aircraft that fits the rules, but also have the hands required to put it where I ask you to, in the way I ask you to. You might post any attempt with any craft for fun, but competing runs must adhere to the following: Procedures & Rules: •To create a fair experience for everyone, mods are not allowed for competing runs, in any form, save for information mods like engineer. Parts, physics or skill affecting mods (such as airplane plus, FAR/NEAR or mechjeb's autopilot respectively) are definitely not allowed. Again, for clarification: NO MODS - Even if not doing so with malicious intent or even knowledge, you might be gaining advantages over all-stock entries. With the tight regulation margins of this challenge, that's something I can't allow. •Create an aircraft that meets the following criteria •Your aircraft, once built, has to take off from the default runway without any kind of assistance (towers for example), and land at the two helipads on the KSC rooftop. The flight and landing have to meet the following criteria: Lastly, to validate your entry, your aircraft must meet the following criteria after completely stopping: As you can see there's no score system, a successful landing with a craft that follows the rules is all you need. I'll probably make a badge or something to include in your signature. TL;DR - Short, precision landing competition for "standard" aircraft, except the runway is the two helipads on the roof of the VAB. Have fun. You can post entries that don't follow the rules as well, but of course they won't count. My attempt, includes F3 screen to show that nothing fell off after that little slide lol: https://streamable.com/7r7mm

This challenge is built for precision, with SRBs. Rules: 1. SRB only. No other sources of propulsion, but having any other resources (including but not limited to EC) is allowed. No RCS. Decouplers are fine for separating stages, but not a major source of propulsion. 2. Stock only. Graphics or informative mods are allowed, though. DLCs are stock. 3. No cheats. No cheating of any kind. No autopilot. 4. Settings requirement: commnet on, plasma blackout on, require signal for control on, part G force limit on, part pressure limit on, Kerbal G force limit on, Reentry heating 100%(or higher if you like). All other options are optional. 5. Orbital construction is OK. If you think there are benefits, and you are capable of doing it. Multiple launches going to different places is not allowed for a single entry. You’re welcome to submit separate entries for that, Scores: 1. Reach circular orbit around Kerbin: + 5pts. Eccentricity between 0 and 0.01, with pe above 70km. Stable orbit required(engines not firing). 2. Flyby another body: +10pts, times body multiplier. Simply enter its SOI. 3. Circular orbit around another body: +20pts, times body multiplier. Eccentricity between 0 and 0.01, with pe above atmosphere, if it is present. Stable orbit required. 4. Land on another body: +30pts, times body multiplier. No damage to the craft, or, no unplanned disassembly (stagings are definitely OK), rapid or not. Stable landing required(engines not firing). 5. Successful docking: +500pts. Docking anywhere is treated the same, but make sure you’re on a stable orbit. 6. Be Kerballed: Double points! Make sure your crew returns safely. 7. Body multipliers: Entries should be proven by video/image and mission documentation. Mission report threads are welcome! Participants: This challenge is open to suggestions, especially for the body multiplier part, which may be not so fine-tweaked due to my personal limitations. Badges: You can put it in your forum signature as you like, if you get any positive points, according to the way you got it.

Hi everyone. I'm not an engineer, so maybe this is common knowledge already, but during TCA development I've encountered a problem with numerical instability of Vector3[d].Angle methods at small angles. Both methods use the same straightforward implementation: public static double Angle(Vector3d from, Vector3d to) { return Math.Acos(Math.Min(Math.Max(Vector3d.Dot(from.normalized, to.normalized), -1), 1)) * 57.2957795130823; } Which is fine, unless rounding errors start producing cosine values > 1 that get clamped, which results in angle "measurements" like this: *this, of course, depends on the vectors themselves, as most of the error comes from normalization. So I've started looking and, soon enough, found a paper reciting a much more numerically stable approach: https://people.eecs.berkeley.edu/~wkahan/Mindless.pdf (page 47, top, don't mind the title ) What's more, as it uses arctangent of direct quotient of sine and cosine, we can use the standard atan2, which is robust at all angles: public static float Angle2(Vector3 a, Vector3 b) { var abm = a*b.magnitude; var bam = b*a.magnitude; return 2 * Mathf.Atan2((abm-bam).magnitude, (abm+bam).magnitude) * Mathf.Rad2Deg; } No normalization, no clamping, and much, much more reasonable results: So if you happen to have the need for accurate angle measurements in Unity, this is a cheap and effective solution.

I have been trying my hardest to design a lander that is capable of surviving an Eve re-entry, and being able to return from sea level. My main problems are first that the lander needs to be quite big and so I need big rockets to haul them into orbit. Sometimes they are not light enough to get into LKO. The second issue is that I am trying to at least land on actual land and not the ocean so Jeb can plant a flag and the rocket can stay upright on landing legs. The problem with that is mainly that I don't know how to do atmospheric precision landings on Eve. Any tips?

Real pilots work in very fine increments. A jet airliner flies at a speed and height precisely calculated to give the lowest fuel burn at the current weight. Adjustments are made with the autopilot or by adding / removing one notch of trim. In the back, passengers pouring drinks into plastic cups never even notice. Harsh manoeuvres don't just spill beverages, they also create drag, so if you're a test pilot looking to set a speed or altitude record you also need to climb at the right angle. Unfortunately when flying with keyboard, control inputs are "all or nothing". At high speed, a brief tap of the S key results in a brief 15G pull-up. KSP joystick support is still patchy, an uncalibrated controller does little better. What we really want is something that lets us adjust angle of attack in one degree increments. When trying to get through the sound barrier, we want to lower our AoA close to prograde for minimum drag, not be stuck at 5 or 10 degrees above or below it like a giant airbrake. During the speedrun, when trying to milk as much speed out of the airbreathing engines as possible, we need absolutely level flight. At these speeds, a climb angle of 1 degree can stop us accelerating, or send us into air too thin for the engines to have power very quickly. A dive of 1 degree quickly sends us down into the soupy lower atmosphere where drag, heating and fuel burn are enormous. Other than autopilot mods, what can our intrepid pilot do ? Technique 1 - SAS Stability Assist lock Simply pressing T activates SAS in it's default Stability Assist mode. In this mode, SAS makes control corrections to try and hold the nose attitude same as it was last time you touched the controls. At high speeds, due to the curvature of the planet, this results in a slowly rising AoA. When it gets too high, pressing any of the control keys, resets SAS's target attitude and drops the nose a couple of degrees. For the same reason, this technique is less useful in situations where frequent corrections are being made , since every time you correct a roll or a yaw, the nose drops, which you might not want. Technique 2 - Pitch Trim Pitch trim cannot be used while SAS is active. However, if your plane is stable enough to fly without it, and you're not in a situation requiring rapid changes in pitch, it can give very precise control. Hold down the ALT key and press S to increase nose-up trim. ALT + W to decrease it, and ALT X to remove all trim. The effect of trim is like pulling back very gently on an analog stick and holding the controller there at the same angle throughout the flight, minus the wrist cramp. Technique 3 - Authority Limiter Adjustment The elevons at the back of the main wing are set to control pitch and roll. Note that as they are behind CoM, they get the nose UP by pushing the tail DOWN. At the front is a canard, currently doing nothing. And we have SAS enabled in Prograde Hold mode, so the rear elevons are controlling our pitch so that we have almost zero AoA. This means our wings aren't producing any lift so the plane is in a dive. After clicking the "Deploy" button on the front canards, they deflect and start creating a large amount of lift that picks the nose up. If SAS wasn't running that would cause the plane to fly with an AoA of about 10 degrees, but because SAS is still trying to hold prograde, it fights the effect by generating lift with the elevons at the back of the ship. This results in the plane flying at about 3 degrees AoA, an efficient angle for making enough lift to stay airborne whilst keeping drag low. Note you can adjust the pitch angle by tweaking the "Authority" slider. If you reduce the "authority" of the canard, it deflects at a lesser angle and our nose drops. If you lower the authority of the elevons that are fighting it, our nose goes up. Here we are doing the speedrun. 17km is a good altitude for a speedrun on the Whiplash - above this height, thrust starts to fall faster than drag. By tweaking this slider, I can get us to fly level here quite easily. This is easy to do because SAS is maintaining control of the plane and I don't actually have anything else to do as a pilot other than play with this slider ! Picture - Elevons lifting the back end, Canard lifting the front. Here's a video of me flying a different craft, where i accidentally discover this technique during the speedrun

I'm stuck at this challenge. Even with this small decoupler having a zero detach force, it still pushes like a small docking port. It doesn't allow you to do precise maneuvers as it imparts around 1 m/s and when you decouple it. If it says zero in VAB, I want zero pushing. Can we have this fixed? Also, if someone knows a quick solution to this, I'd really appreciate it.

Jenga with a twist: Take two vehicles, each crewed by a Kerbal, and land one on top of the other (one of them necessarily has to be able to fly). Here's the catch: your flying craft must then lift BOTH vehicles and carry the total weight OFF THE GROUND for a minimum surface distance of 1km, at which point the other vehicle (necessarily wheeled) takes over and roves both vehicles - still mated together - back to the start point at the West end of the runway. Prohibited mods: anything with a cable attachment (winch, EVA/dynamic struts, etc.) such as KAS/KIS. Use the stock docking ports. Anything else is OK. Vehicles may NOT share fuel or power sources. [Challenger's photos to follow]