Somerled

Tosh Sunbeam, LV-N's, and Netflix (Twitch as substitute).

I see you're using some mods. Are you sure you haven't grabbed some non-stock parts with different stats than you are expecting? For instance, I'm having a hard time believing that what looks like a FL-T400 fuel tank in your image is the same as the 0.21 stock version. It's too short based on where the legs are placed. The banding around the bottom doesn't look right either. Could it be much heavier than the stock version? What about the engine? Is it also a stock LV-909? The fairings look to be too short, but it's hard to tell given the perspective (and that could also mean a goofy connection to the decoupler). Since I haven't been to the Mun in 0.21 yet, I thought I'd take your lander and give it a test. To confirm: I used the LV-909, FL-T400, Command Pod Mk1, Mk16 Parachute, TR18A Stack Decoupler, Telus-LV Bay Mobility Enhancer, and four LT-1 Landing Struts. All stock parts (no mods installed). That's also Scott Manley's design in the vid you linked, with a different ladder setup and no ASAS. It lands just fine at 1km elevation on the Mun. Weight is not an issue in the least. Fuel isn't a problem either; I landed took off and landed again 1/4 around the Mun with fuel to spare. [Edit: scratched the rest, seemed irrelevant]

Beware that there are features on the Mun's surface above 3km, and the 0.21 Munar surface may have features above 4km [citation needed]. Frederf's plan is what you want to aim for, but be prepared to add some altitude during your final burns if you see you're flying too fast straight into a mountain.

Don't the old SAS parts have the new ACS, just like the pods? If you activate this and then detach the parts, would they continue to stabilize without any manner of player control? Stabilized debris might have its uses, and elsewhere someone mentioned something about command seats.

I have only one design rule: to minimally engineer a craft for the desired mission. The idea is that if I can't get to space, get to another planet, circumnavigate, or whatever my aim is, then the chances are higher that I'm simply flying it wrong, not designing it wrong. As I perfect my handling of every craft as much as possible, it turns out I can squeeze oodles of performance out of even the most underengineered flying bathtubs. I save airhogs for my silly days, when my mission is just to create fire as fast and as often as possible.

So I'm going all Kerward Hughes and ramping up my aircraft industry. Now, I've settled on a working design and I'm aiming for Kerbin circumnavigation. The thing is, I'm obviously getting different fuel efficiencies at different altitudes, if efficiency is measured as fuel used over surface distance traveled. Well, duh! Drag, surface speed, thrust and lift profiles, all of that stuff matters for making my plane fly the farthest. I want to ask the Lindkerbs around here what they think of my flight SOP. What I'll do is get up to my maximum safe altitude as fast as possible, then use turbojets on low(ish) power and trim to a pitch that maintains airspeed and altitude. My thinking is that there's minimal drag up there, so I can get up to higher speeds using less power. However, there's also minimal lift, so I have to spend more downward thrust to maintain altitude. There's also engine intake and ISP to consider. I have no feel for the tradeoffs between high- and low-altitude flight in relation to fuel efficiency. Anyone care to straighten me up so I can fly right?

Most explanations, intuitive or not, seem to miss the point of the Oberth effect. It's not mechanical force acting through a distance, since it's valid for impulsive forces (and is described as such, in fact). It's not the mechanical or chemical work of the propellant/rocket system, as it's valid for any system where a mass (of any proportion) is ejected from a system. And momentum is not affected: you'll always get the same delta-v from the same burn (notwithstanding any other physical effects) regardless of velocity or position within a gravity well. It has to do entirely with how you define your reference frame. Oberth originally described it between two systems, one considered at rest and one considered in a frame moving with a velocity oriented with the direction of motion of the mass of interest (the rocket). Kinetic energy, and therefore a change in kinetic energy, relies on the reference frame you define it in, and only this change in energy for the rocket is larger in the moving reference frame. Oberth supports this by proving that energy is conserved, momentum is conserved, but the mass of interest receives more kinetic energy in the moving reference frame versus the stationary reference frame. And the choice of reference frame is arbitrary. Want to see this in action? Get a rocket into orbit. Any orbit will do but to ease your mind, make it circular. Now, click on your speed readout above the nav-ball to change between surface and orbital speed readouts. Notice how it changes? Your velocity within an inertial frame (relative to the universe, you could say) never changed, your mass never changed, nothing in the simulation changed; but your speed does change between these two reference frames. Therefore you'll have a different kinetic energy in either of these two frames. Lower surface speed to zero and you'll still have orbital speed. Go one step further and do the math on your change in kinetic energy (0.5*m*v*v before and after the burn) for both frames and notice the difference. Bang! Proved Oberth in a game. In short, energy itself is relative. The binding law for energy is only its conservation, which is also relative. It's a meaningless term on it's own (similar to pressure or electric potential). Energy gains meaning only within its frame of reference. As such, it's less of a physical quantity and more a means of relating how physical quantities change in relation to each other. Quick quiz: according to Oberth, will your change in kinetic energy be larger if you burn retrograde instead of burning at rest? Answer: no, but your exhaust's will.

Lagstation deorbit:

Oberth effect (from wikipedia): the use of a rocket engine when travelling at high speed generates much more useful energy than one at low speed. For us, the operative word is "useful." The most useful energy you want to change in an orbit is your specific orbital energy. Like kinetic energy, this changes as a square of velocity. If you start your burn while moving faster, your SOE increases much faster. Mathematically, this is due to an extra term appearing as a result of the square of velocity (find an equation for SOE and do the math, V+dV, it won't take long). Physically, you must consider your reference frames: your orbits change in very different ways at periapsis and apoapsis. One change is more efficient than another in imparting orbital energy to the rocket. Intuitively, we think of gaining delta-v, but that's a term relating directly to burn times; our true goal of using delta-v is to change our energy, which changes as a square of velocity.

Philnard Kermin: Son of Kraken! a.k.a. playing with the North Pole singularity.

Did some fancy flying to land an SSTO spaceplane on the Mun. Came in extremely shallow, retro burned upside-down to lower my landing speed, then pitched all the way over, only meters from the surface, to come down on the wheels. It's such a different experience from any other landing I've done. No vertical descent, no hovering to a setdown, no atmosphere to provide lift or drag. Horizontal speed had to be below 20 m/s or the plane would just bounce off the surface. It's been a good day. The XSSTO III is a modified Aeris 4A: less weight, more lift, shifted CoM, wider gear placement, and a flintstones parking brake. Oh yeah, update. I didn't have enough damn oxidizer to get off the surface. So I stupidly heroically tried to land at 320 m/s. Brave Philnard EVA'd from the cockpit, which was ejected from the wreckage. He did actually survive the crash and awaits rescue. I love KSP!

My first mission to Jool started with a bad omen: my intended target was Eve, but I left Kerbin SOI in the wrong direction. So, I quickly changed the mission parameters and luckily managed a Jool intercept with a Duna assist. I hit the Jool system with almost no inclination and even managed to aerobrake through Laythe to close our orbit. Despite not wanting to even go to Jool, I was set up pretty nicely with a low delta-v corridor. I figured my first stop would be Bop. Not too easy, not too difficult. Again, I got lucky and had a nice and easy burn to Bop's SOI as I was finishing my Laythe aerobrake. It couldn't get any better. As I approached Bop and was preparing to enter orbit around it, it finally hit me: I had entered the system on a clockwise orbit! Every body of interest was orbiting opposite my direction, wasting all my delta-v to achieve any orbit. I didn't want to just scrap the mission after hitting so many perfect burn windows on accident, so as I neared Bop, I burned off every ounce of fuel in my rockets, sending my ship on a dive to Jool, and sent my one-seat lander to park around Bop. The ship was carrying two of my most valued heroes, Mallie and Sherburry, who had each set some amazing records (Mallie for the first to walk on Duna, Sherburry for the first to leave and re-enter the atmosphere). As they descended through Jool's atmosphere, Sherburry stayed with the pod and Mallie EVA'd. To this day, she's still standing on the 'surface' of Jool, waiting for a ride that can never come. I only just noticed yesterday that she's listed in the tracking station as 'Landed at Jool,' and her marker is only visible in the map view during flight, like a beacon of tragedy only for Kerbals to see. Turns out, while I was dealing with the last moments of the ship, the lander had disappeared. I must have put it in too low of a polar orbit and it smacked a high mountain as the orbit rotated around the moon. So ended my mission to Eve.

[snips - double post]

That's quite brilliant, actually. I have a bad habit of just dumping my craft in their parking orbit (usually with a loader probe that trashes itself afterwards) so they end up facing any damn direction. Orienting docking ports along N/S is a perfect guide. Say, fly north of your target, orient to south, burn and RCS correct to dock. Three easy steps. Though, I'm thinking displacing above/below the orbital plane gives you possible collision points at the AN/DN. Even though docking is a controlled collision, it's possibly something for time warpers to think about, maybe?

Took me a couple hours back in 0.15; I think, whichever version introduced folding landing struts, i.e. soviet docking clamps. Most of the time was spent within 1km, lining up and approaching the two craft just so. There was no targeting assistance, no magnetic dockotrons, and the craft not being piloted would always tumble ever so slightly. The last of a handful of failed captures ended up with a landing strut spinning away ... so I declared "Mission Accomplished" and made a grand fireworks show in the upper atmosphere to honor the heroic Kerbonauts (shame they didn't get to see it).

Since the math never works for me, I do something more or less the same. I do it instead by aligning the orbits as close as possible, then adjusting phase. The phase part is fun (for me at least). If you\'re lagging behind, then decrease your apoapsis; too far ahead, increase apoapsis (all adjustments done at periapsis, obv.). Correct as you get closer. No math, and just a few more burns than necessary. I like it because you have to burn away from your target to get closer. Squeeeee orbital mechanics!