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Hagen von Tronje

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Posts posted by Hagen von Tronje

  1. Yep, as I said on flat terrain it will do what you want it to do: by trying to keep your pitch and roll at zero it will be keeping the plane of your wheels aligned with the terrain. It's hills where it won't work, particularly if you try to turn while on a hill, where it may actually cause you to flip

    I wonder if the fact that I've never relied on reaction wheels at all on my rovers, and even disable torque on some cockpits and probe cores that go on them, is part of why I seem to have such a different experience. I hear about people adding enough torque to straight up flip their rovers; mine don't have enough torque to do more than very slightly adjust pitch if I get air.

    Just a thought. Almost all my wrecks involve racking my undercarriage on terrain spikes, a hazard that I'm sure everyone is well familiar with; I almost never actually roll a rover over. I don't think that I'm nearly as good at this game as a lot of folks so I wonder what is making the difference. I sometimes suspect it is because I rely solely on directed force (dead weight, direct downforce, limited control surfaces, etc) rather than torque.

    Could be that SAS with lots of torque is bad news. I have never driven one for any distance, I disliked the way torque-heavy rovers handled immediately on testing.*

    *EDIT: Exception is playaround craft using anti-grav plates, I've used torque to steer those. But those obviously don't contact the ground.

  2. I run the OS on an SSD and I've tried KSP on the SSD, but it doesn't impact KSP loading times for me*, not even the initial load. I run other installs off the HDD and it's no worse; a pure stock load on either is about 20-30 seconds on my computer, and increases about the same on either disk as you add mods.

    To be clear, this isn't to say SSDs aren't much faster. I game off mine all the time and love it, but KSP somehow seems to avoid benefitting from it. In fact I'm thinking I will migrate the SSD install just to avoid wear on it.

    *Having the OS on SSD might improve KSP load times, I haven't run an HDD install OS to compare.

  3. Fair enough, I was actually referring to Stability Assist with my above post, I always forget that pilots can do that now, I never use it.

    To actually answer your question: I wouldn't think so. If your craft is thrown off course due to (for instance) - atmospheric pressures, the SAS won't try and hold your original heading, it will hold the new one once everything calms down. I'm assuming there is a certain tolerance there, but the stability lock will be lost eventually.

    If I'm wrong (and it's been known to happen occasionally), a better option may be to hold prograde? I presume your rover is going to be moving forward, so in theory that should do it (as long as the initial incline isn't too steep, otherwise you'd smack into the slope, as your prograde would be underground). I'm not sure if the prograde lock will hold your roll angle though.

    Just my experience, but holding prograde in a rover that has reaction wheels (or torque from a probe core or cockpit for that matter), or RCS/downthrusters for stability, is a great way to make minor bumps into full blown rollovers. Any time prograde undergoes unexpected changes, such as when you leave the ground however briefly, the rover will of course attempt to follow that prograde change, which can be disastrous when what you really want is to just hold level and land on all wheels.

    Stability assist gives good results on a lot of rover configurations. It tends to be surprisingly not-terrible at keeping wheels in contact with the ground and doesn't try to override your inputs. With rover wheels it seems to function almost like an ESC, if you drive along a slope it seems to adjust wheel speeds to "pull" you into the direction of best contact with the ground (i.e. the direction least likely to make you flip) if you let it; this can easily be overridden if you feel like you're going too far off course.

    Keep in mind that if you introduce real thrusters, or control surfaces in an atmosphere, you'll face input from those too, so rovers built with those systems will need them adjusted properly (note: control surfaces can be excellent for stability in atmospheres!). I find these types benefit from stability assist even more though, since they tend to be pretty fast.

    I've done all my circumnavigations with SAS enabled almost the entire time, I personally at least think it makes navigating things like hillsides a whole lot easier. YMMV.

  4. I'm thinking one approach would be to make a rocket SSTO with ISRU rated for both Tylo and Laythe, and a separate, staged Eve lander/launcher, both somehow stuck to the sides of a mothership transfer stage. The lifter isn't as tricky as making the SSTO and Eve return capsule docked firmly enough to be liftable rather than docked in orbit, and the whole thing stable enough to not be a disaster. The entire Eve vehicle can be ditched very early if you do Eve first, and at that point it's not much different than any other grand tour.

    Another thought, you could even attach the vehicles separately from how they will dock/fly in space and dock them to each other in orbit, no? Rules are one lift, not no orbital assembly.

    Not to say this is easy but I think it's plausible. Each step other than somehow sending it all up in one package has already been done by someone.

  5. I'm 99% sure that Randazzo's answer is pretty much the whole of it, at least in-game. Realistic or not, ablator lifespan is pretty much a function of how long the heat shield spends exposed to skin temperatures above 600K. Longer reentries will indeed consume more ablator even if they are gentler reentries, so in cases where such things matter, an "optimal" reentry will presumably want the shortest reentry trajectory possible without exceeding the skin heat threshold of any parts not fully occluded during reentry.

  6. Hmm. Do you have SAS on or any other control system? Sometimes SAS and/or parking brake causes endless jitter, though usually on slopes. It would certainly appear that you're on Minmus's flats, which should be a literally ideal surface, but with unorthodox craft designs I guess maybe it could cause jumping? Or maybe misaligned wheels as was suggested, using snap to angle when mounting wheels can bring this out without even noticing.

    It might also just be those wheels, I build several rovers a week and yet still never use the model 3 wheels because they seem to bug out a lot to me. YMMV but I've had them do nonsense like hurl me into the sky or convert my entire craft and anyone in it to cubist spaghetti.

    I've had this same problem before, I believe it's a bug. The only way I was able to fix it was by putting landing legs on the rover, and deploy them when landed.

    You can also try editing the save file and change the state of the rover to landed, but in my experience even that doesn't work, the rover just jumps right back off the surface.

    What happens if you timewarp? When I did, the rover exploded!

    Curious, was it using the huge wheels like this one is? Just trying to find some common thread to this. Of course, with just what you've said, it's also possible you were on a slight slope with either SAS or brakes engaged as described above, I've certainly had that happen to me in all manner of rovers.

    The timewarp explosion is because the craft is being registered as "in motion" and so with physics off it's just crashed into the surface.

  7. Hagen, I've got Planet Shine. Are there any other visual enhancement mods available at the moment?

    I just finished the cave man challenge so I'm up for the Elcano Challenge. I'm building my rig as we speak. I Can't wait to test my rover :D


    AVP is what I use, provides a range of nice effects from auroras (on multiple planets), dust storms, snowstorms, clouds at multiple altitudes, the works. Everything is optional/configurable so if you start running out of memory or if one of the effects bothers you, you can remove it.

  8. The plane I sent weighs just about 10t with payload and has about 8 lift available. But it's also sporting a .83 TWR which goes a long way, it's pretty floaty on lift alone. So I'd say 1:1 is a decent reference point.

    In stock your thrust options are Dawn ions or rocket engines of whatever flavor (RAPIERS certainly operate, in rocket mode). In an ion glider you're likely going to want a lot more lift, RAPIERs can likely keep a decently built plane aloft without much help so wings would be largely for control surfaces - which is important, it's not easy to turn in Duna's atmosphere, at least compared to Kerbin.

  9. Thanks hagen for your kind reply. You've convinced me to try and circumnavigate minmus. I'm currently working on the cave man challenge but when I'm done with that i will try to circumnavigate minmus. I can't wait. :)

    I do have to read up on the whole braking bug issue. Never heard about that before. :)

    On a side note. ...aren't the biggest rover wheels capable of withstanding a velocity of 200 m/s ? (I can't check because I'm not at home) It sounds like they would work well in these situations.

    The braking bug is probably the source of a LOT of gripes about rovers. Whenever you tweak a wheel, the brakes will go to a fraction of their effectiveness, and will never go back to full, ever. The bugfix gives you the normal braking torque range, so you can tweak them anywhere from dangerously stiff to nice and gentle.

    Out of stock rover wheels, the tiny wheels can take 20m/s, the balloon and ruggedized wheels can take 60m/s, and the huge XL3 wheels can take a paltry 30m/s, not that they can go that fast. The huge wheels also work on a cantilever and have all the maneuverability of a drunken cow, if you can do an Elcano with those, my hat off to you and mad respect, I can barely make a functioning rover with them.

    Unfortunately with stock wheels there's little question that the ruggedized are the wheels of choice. Balloon wheels are actually almost as good, main problem is, they're the same thing, just slightly inferior, and offer no even situational advantage that I know of. They're even more power hungry!

    Wheels themselves are actually really durable though, I've almost never had a wheel be the thing that blew up on me. They can be repaired infinitely in the field even in stock so feel free to use them as bumpers, I certainly have and they work great for that. I find it's a lot more common for impacts to transfer force through the wheel, jamming it into the chassis and blowing that up, or for minor irregularities in the terrain to poke up and rack your undercarriage or chassis and blow it up that way (they can be REALLY hard to see unless you're driving with your camera down under the vehicle!), hence the conflicting interests of ground clearance and low CoM.

    I look forward to seeing your Elcano! I might also suggest, if you're not already, consider visual enhancement mods. I know that sounds meaningless, but when you spend dozens of hours looking at a planet, it's nice if it's fun to look at! :)

  10. If you'd like to seek anomalies using a reasonable gameplay-involved mechanic, try SCANSat. A satellite in orbit can produce maps, including locating anomalies on the surface. You'll still have to make a vehicle that gets to that anomaly and use the map to pinpoint it, so there's some hunting involved. It also will not immediately tell you what the anomaly is so it will still be a surprise when you get there.

    Also be aware up front that some listed anomalies either no longer show up, or only show up on higher terrain detail. If you're very sure you're in the right place and can't find anything, look it up - some are just plain gone or buried underground now and there's no sense wasting your time hunting for something that isn't there.

  11. I kind of understand not having a manual, for KSP it would be a huge document, a wiki is better suited to such a huge game.

    There is access to the wiki, I'm personally working on updating it! It is experiencing migration problems, but the devnotes said that the server would be fixed soon. Anyway, the migration problems only affect some image stuff, not content. Join the wiki! It's easy, and you don't have to add anything if you don't want to.

    I'd heard similar vague mention of problems, but if you're saying it's all good now then I may try to update some of the planet articles, I'm pretty sure a number of them have outdated or incomplete information.

  12. How long does it take to perform a typical circumnavigation trip? This thread ignited some interest in me but it still sounds like a 2 hour waiting game. ... (even without all the crashes). The engineering part sounds like a really cool challenge though. :)

    Depends on where it is and what you'e driving. Minmus in a rocket sled could probably be done in a few hours. My Kerbin route took me 45+ real time hours (not game hours, it took me 11 days in game, I used physics warp frequently), maybe more, that's just an estimate.

    It's not just a waiting game, though. You will likely encounter some very hostile terrain at some point, and getting through that often takes some resourcefulness, particularly if you don't want to pull your hair out. However, they are typically very lengthy missions, for obvious reasons.

    If you'd like to try an Elcano, I suggest Minmus. It's got some of the smoothest terrain, it's got flats that will let you shave hours off your drive, it's got interesting sights (at least IMO), and the low g does provide an engineering/driving challenge to overcome. It's also one of the prettier and less oppressive places to drive IMO. If ends up boring you, it only takes a few hours to complete and you'll have it under your belt rather than giving up, and if you like it...there are a lot of planets and moons! ;)

    One nice thing is that because Elcanos are meant to be adventure challenges and mod parts are permitted and even encouraged, the nature of the drive is up to you! You can choose to set a land speed record on flats or you can choose to go mountaineering or boating, you can take a caravan through the desert, you can drive a train! You decide which mountains you climb, which gullies you dive into, which glitched terrain you endure for the wacky screenshot. You even determine the conditions you drive under, you can do all daylight driving or take the night as it comes, and all of those things completely change the character of the challenge.

  13. Duna is started - and completed! Includes a prelude detailing base construction for your enjoyment.

    Turns out Duna has some of the freakiest terrain I've ever seen and looks like it's about to burst at the seams. Read to find out what the kraken dragged in!



    Both Kerbin and Duna now complete! And I'm going to your favorite place next for an equatorial, amphibious circumnavigation of Eve, so that's gonna be good times. ;)

    BTW if you ever make a flat, low profile version of your spotlight for use as a landing or survey light for planes, I will...have very kind things to say about you, and will praise your name with high praise. I love that light so much I want it on every vehicle! :)

  14. Duna is up, and completed! Includes a prelude chapter that is not part of the official Elcano entry, but gives some background on the base construction and mission design.

    This was a much more elaborate mission, it took dozens of hours of planning and construction, not to mention launching and transferring, to get the whole thing in place. Ironic that the Elcano turned out to be a breeze and Duna turned out to have a lot less than I thought, but hey, I think I did good, and the base looks pretty sweet to me!

    I'm thinking I will do Eve next. I was planning to do Ike immediately, but after driving around Duna on treads, I think I'd like a faster rover for Ike. We'll be back. Eve is the big one, the scariest planet of them all. It needs no introduction, and it needs no help from horrifyingly glitched polar terrain to make it a terror to kerbalkind, so I'll be taking an equatorial route on Eve, just to keep things fresh. I've already got a base there, and the rover is delivered, so I hope to have updates soon!

  15. Airbrakes seem to work pretty great for me all things considered, the main problem is that they aren't going to be enough drag for the kind of titanic lifters that Eve demands to get back up. Good for orbital drops of cargo that won't be coming back up, maybe less good for what you have.

    I managed to land a 1000t lander on Eve as a new player (don't interpret that to be skill, it was purely persistence outweighing common sense), and pretty much what I did was retroburn a whole lot. Like empty out the tanks retroburn. This didn't matter because I had ISRU, and it also didn't matter because it turned out the lander was in no way capable of ever leaving Eve again and the whole thing was a silly idea, but the point is that it landed with minimal exploderating.

    If you can send down something with an ISRU unit and a claw (it would not need tanks of its own and could probably land with airbrakes and chutes only), and wheels so it can get up to the lander, you could use all the fuel you got retroburning into the atmosphere until you aren't catching fire, then deploy chutes for your happy landing. This means the only modifications to your design if it already launches is to decide if you need airbrakes or any of that other stuff anymore, so win/win! The catch is that you have to land the ISRU unit close enough to your lander that you are okay to drive it to the lander for refueling. Eve is hard to precision land on but easy to drive on if you ask me, so...might take a few tries but probably doable.

  16. A ship that can land on any planet or moon and come back to Kerbin is a monumental achievement of engineering and is going to carry numerous redundant systems (landing on Tylo is not landing on Laythe, taking off from Eve is not taking off from Minmus). For most KSP players building something like that would be their crowning achievement.

    If you just mean "how do I start exploring," I'd suggest doing flybys to inspect a place first, then building something to suit the destination and mission requirements. Duna landers don't need tons of fuel or thrust and can make some use of chutes, while Tylo landers need truckloads of fuel and thrust and chutes are worse than nothing at all. Interplanetary landing and return missions are significant projects so plan out each phase, how you will transfer to that planet's intercept, how you will land, how you will get back off that planet, and how you will get home to Kerbin, then whether you will land that vehicle back on Kerbin or just pick them up in Kerbin orbit with a rendezvous to save the trouble. Additionally, plan what you want to do there - it's cool if you just want to land and poke your head out, but you might want to take the opportunity to collect samples, test out a rover, set up a mining base, scout out sites for future operations, etc etc etc.

    The short version is that you keep trying until it works, then you keep getting better at it until you can take the next step! ;)

  17. I disagree. For any given design, optimal ascent in absence of atmosphere is to burn prograde and circularize before you pass Ap. Up and to the side has more cosine losses than launch at angle theta hold prograde and control throttle to both avoid mountains and circularize at Ap.

    You essentially want to turn an elliptic orbit with you at the Ap traveling a surface speed (with 1g constant radial thrust) to a higher circular orbit. We all know that the most efficient way to raise an orbit at Ap is to thrust prograde (horizontal). The radial (vertical) component is to push Ap ahead so we don't pass it and lose altitude (or hit a mountain). You want to minimize it as much as possible. Better to pay the cost as a trigometric fraction of that requisite prograde thrust.

    SAS function to hold heading relative to horizon would be godsend though.

    Not sure I follow. On initial ascent, prograde is wherever you point the rocket. Of course you will have to circularize with a prograde burn and you will want to do so at Ap. As I understand it, horizontal speed is retained, vertical speed is wasted after whatever it took to get you to safe altitude, hence why levelling with the horizon so your dV is going toward horizontal speed, no?

    To be clear, I'm not talking about what you do to create the desired orbit out of a suborbital trajectory, I'm talking about the procedure from going from surface to suborbital so you can do that. Maybe I'm an idiot and missed something, but I think if you stick SAS on prograde starting at ascent then do nothing to adjust your AoA, you're going to go in pretty much the direction you were initially pointed and nowhere else, so unless you can somehow adjust your rocket to your desired AoA on the ground, you're still going to be flying the initial part by hand until you get enough speed to safely start maneuvering. To be fair, I have little experience with nonatmospheric HTO ascent vehicles, so maybe some of you genius designers have made easily adjustable AoA takeoff craft, in which case you rock! :)

    But what do you mean about controlling throttle? Common wisdom seems to be that when fighting gravity, max thrust is king because less goes to waste. I can certainly see throttling up to avoid flying into a mountain face, but I wouldn't throttle down if I was pretty sure I was already clear of the mountain, I'd lower my AoA so my thrust is going in the direction I want, or I'd cut thrust entirely and just straight up prepare to circularize at low altitude when I get to Ap.

  18. Hey hey hey, a topic where I know useful things! :)

    On design:

    - I feel like your CoM is pretty high, at least for what I like. If you want more ground clearance, you gotta spread the wheelbase. You have a good idea with the I beams, try longer ones and see how it works. Or just stick the wheels out the side. But really you could bring your "belly" down to where your suspension currently is, if you clothesline that undercarriage you're toast anyway so no reason to feel like you need to protect the fuselage.

    - Don't forget to tweak your wheels! Steering with wheels that have enabled motors is method #1 to flip any rover. If you're using Claw's brake bugfix (you probably should, it really is a bugfix and really does help), you may need to tweak brakes to have enough to stop you but not so much to flip you.

    - Downthrusters. RCS thrusters are a popular choice, but I've found the most efficient method for me personally is to use either Twitch or Puff engines. This is because you can limit their thrust and throttle them for on-the-fly, as-strong-as-you-need-it downforce. Other engines work, including Dawn, Ant, etc, I just find those two to be the preferred type for me. See comments on driving below.

    - Ballast. Does that sound crazy? Actual mass = "free downforce." Assuming of course that mass is keeping your CoM low. Fortunately, KSP gives us an ideal ballast in the form of LFO, which is dense, transferable, and fuels the downthrusters. If you're concerned about putting more mass up, you can send it up with empty tanks, then dock and fill it on the Mun. For a circumnavigation attempt, you are almost surely going to want to carry lots of fuel for downthrusters anyway, and maybe want/need to refill them too. The only downside to more mass is that impacts will be more damaging to wheels, huge n' heavy rovers will break stock wheels with regularity just bumping into terrain edges.

    - Moar wheels. This also sounds crazy, who drives cars with six or eight wheels? Folks who need lots of traction, that's who - dualies. We don't have dualie wheels, or a great selection of wheels of differing profile, so we make do with more wheels. The trick here is simple - more area contacting the ground = more traction. Hence why tanks use treads (among other reasons). Worth mentioning that the motors in the wheels, true to life, seem to have really amazing torque, they will do their top speed of 25m/s even with pretty heavy loads!

    - Minor factoid I remembered: 1 RTG = 1 fully powered wheel. Unpowered wheels don't use juice even if they have steering enabled and powered wheels only consume EC when actually running the motor. Not that you have to use RTGs but this is a nice thing to know. However you don't have to have full power at all times, especially on Mun where you can coast nearly 90% of the time without hardly losing speed, so in practice you may need less power than you think. Not that I mind your overengineering, I admire it!


    - What it really comes down to at all times is traction. Downforce is about traction. Flipping is about losing traction, or getting uneven traction. Think of traction like a resource; any action you take uses part of your traction budget. Accelerating, braking, turning, all use traction, just like in real life. Unlike driving on a well maintained highway under Earth gravity, your total traction budget may subject to change without notice, which is what trips folks up (besides the fact that driving on Mun gravity reduces it significantly already). The problem is you can't see this resource, you have to guess at it. However, without seeing it you can still know that when you turn, you should neither accelerate nor brake, for example.

    - An extension of traction is slope. Going uphill gives you better traction, gravity is pulling you down the slope, and you are driving into it, so your wheels get good contact with the ground. So long as the slope isn't flipping you backwards, going uphill will be to your advantage in low gravity. Going downhill is of course the opposite; you are driving "off" the slope so your wheels have poor ground contact and hence poor traction. As a result you can go faster uphill but must take it easy going downhill; I advise coasting, tapping the brakes or reverse as needed to control speed, and engaging downthrusters if needed.

    - Avoid driving parallel to slopes, this is yet another wonderful way to roll your rover. Whenever possible you probably want to go into slopes straight on; when tackling more severe slopes where doing that is itself hazardous, you can snake up or down the slope, but you must be very careful, and practically stop when you make the S turns. Such maneuvers should be have a very wide "wavelength", just swerving back and forth in a generally forward direction is usually worse than just driving straight forward, but going in very broad waves can let you ascend or descend unreasonably steep slopes if the rover has a low enough CoM to not roll over while doing so.

    - Downthrusters are not something you have to run all the time. You don't want to, that's a waste of fuel. You'll need them when you make turns, when going downhill sometimes, and when you want to brake faster. Plan your turns; on the Mun, you should drop speed below 15m/s or so, then engage downthrusters, then begin a turn to a planned heading. Once you're stable on the new heading, turn off downthrusters. If you used engines with a throttle, like the Twitch, you can selectively use minor downforce for simple corrections, or heavy downforce for emergency evasive driving or if you panic. After a little driving, you should get a pretty good feel for how your rover behaves in the environment you've put it in, and how much downforce you want at which speed to make desired turns. Keep in mind the simple rule that the more downforce you use, the more traction budget you have, the more aggressively you can spend said traction (such as with a much tighter turn radius).

    - SAS stability totally works in a rover. Keep it on, and when it tries doing a little correction steering, don't immediately override it. Even driving a straight line is much easier with SAS on. You probably do this already, but if not, I'm not kidding, it's great!

    - Driving fast mostly means driving a straight line either gently uphill or on extremely level ground, and having enough downforce to deal with whatever terrain variances you encounter. On Minmus's flats, this a cakewalk, no downthrusters needed just don't make sudden high speed turns. On most of the Mun, this means jockeying the downthrusters diligently without being wasteful of them, and also picking out reasonably straightline paths between craters and holding to those vectors as well as terrain allows. Rough terrain is rough terrain, though - if you want to drive up and down mountains, you go slow up and slower down.

    Really truly speedy rovers that go even 50m/s+ consistently are gonna use all landing gear or mod wheels in all likelihood and IMO are a whole different category of build. They're much harder to make, harder to drive, and typically less versatile (rover wheels have potentially unlimited "dV" while rocket sleds do not, to say nothing of the difference in how speed is being acquired). They sure are fun though! But I'll let you in on a secret: physics warp can totally work with a rover. At x2, you should have mostly normal physics still, and in fact I almost always drive on x2 even when making cautious maneuvers. x4 might require you to bugtest the rover to make sure it doesn't do wacky crap when the physics inconsistencies from that warp level creep in, but you can absolutely speed across gentle terrain at x4 in many places. One great thing about this is that you get the "let's go faster" feeling but so far as the game is concerned, you're still driving whatever your actual speed is, so you won't actually be any more prone to going off the rails than normal, provided you can keep it in hand (and it doesn't spontaneously explode, many part combinations seem to do this so really do bugtest this).

    Sorry it's long and I ramble. I bet you can tell I love rovers. I hope this helps, and good luck in your adventures! :)

  19. I may be mistaken in this belief, but I think the "optimal" ascent profile on any nonatmospheric body is to level the navball with the horizon marker and keep it there as soon as you have enough vertical speed to clear the highest obstacle in your path.

    Indeed I sometimes find myself wishing SAS had a "hold horizon" function, because I do the same thing when gravity turning off Kerbin if I've nearly put my Ap up to desired altitude but I still want to burn off the rest of this first stage before doing space maneuvers.

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