Kerbal X now Mun-capable

[FlyingPete]

It's been a while since I've played with the stock Kerbal X spacecraft, but while messing around setting up my gamepad controller I've found that it's now capable of landing on the Mun and returning safely Previously it was slightly short of delta-V, just as how most of the stock craft are intentionally flawed in some way. Seems the changes in part spec in 0.24 were enough to push its performance high enough- you can now get it to orbit on the first stage+boosters alone.

[SpacedCowboy]

Do tell? I think I was still pretty new to KSP when I realized most of the stock craft were kind of "iffy" at best, and avoided them like the plague.

Guess I'll have to re-check them out. Nice catch!

[KerikBalm]

I guess that happened when the mainsail was buffed in response to the NASA ARM additions which made the old mainsail obsolete (I still think it is, but not as badly now)

[Renegrade]

It's been a while since I've played with the stock Kerbal X spacecraft, but while messing around setting up my gamepad controller I've found that it's now capable of landing on the Mun and returning safely Previously it was slightly short of delta-V, just as how most of the stock craft are intentionally flawed in some way. Seems the changes in part spec in 0.24 were enough to push its performance high enough- you can now get it to orbit on the first stage+boosters alone.

Yep, I did a 'there and back' IN 0.24, it's definitely Mun capable, mostly thanks to the 2.5m engine buffs. I even did that controversial directly-from-the-surface ascent on the Mun (which only works if you're somewhere near the Twin Craters since the Mun is tidally locked):

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Don't worry though, there's still plenty of improvements to make. Starting with the nosecone and poodle that pushes only 2.5 tons...

[FlyingPete]

I think the main change was the increased ISp of the mainsail engine. The poodle also dropped in mass which will have helped a bit (must do the delta-V calcs somewhen.)

I think the point of most of the stock craft is to provide the beginner with something which works, but can is flawed in some way. Thus prompting you to think about improving the design before developing your own craft. In my experience, the Kerbal X still has one flaw in that the asparagus stages collide with the core on staging. The vehicle still works though, as the decoupled stages just tend to blow up their nose cones on the way down.

[Renegrade]

I think the main change was the increased ISp of the mainsail engine. The poodle also dropped in mass which will have helped a bit (must do the delta-V calcs somewhen.)

The mass drop for the Poodle helps quite a bit (would have added about 110 dv to the top stage, plus some more to the lifter stages) - plus the more efficient Mainsail. The entire 2.5 line got buffed.

I think the point of most of the stock craft is to provide the beginner with something which works, but can is flawed in some way. Thus prompting you to think about improving the design before developing your own craft. In my experience, the Kerbal X still has one flaw in that the asparagus stages collide with the core on staging. The vehicle still works though, as the decoupled stages just tend to blow up their nose cones on the way down.

The boosters colliding with the core is a bug more than anything... The craft has plenty of flaws without that bug. For example, I threw together an XI version (I'm certain I've done this before, but what the heck), and it went from 72,420 space bucks/78 parts/9 stages to 53,456 space bucks/45 parts/6 stages, with a 400 dv increase.

Personally though, I don't think this "improve a flawed craft" concept is good idea at all. I never used these stock vessels (I wasn't aware that they were included to begin with), and I developed my own style of rockets. If I hadn't, I might be making Kerbal-X-looking designs today. Plus, users might end up learning the flaws as 'features'...

[samstarman5]

Kerbal X has actually been Mun-capable from its introduction. What it is not capable of as it is currently built, is returning back. Even Scott Manley has not managed that feat.

The mass drop for the Poodle helps quite a bit (would have added about 110 dv to the top stage, plus some more to the lifter stages) - plus the more efficient Mainsail. The entire 2.5 line got buffed.

The boosters colliding with the core is a bug more than anything... The craft has plenty of flaws without that bug. For example, I threw together an XI version (I'm certain I've done this before, but what the heck), and it went from 72,420 space bucks/78 parts/9 stages to 53,456 space bucks/45 parts/6 stages, with a 400 dv increase.

Personally though, I don't think this "improve a flawed craft" concept is good idea at all. I never used these stock vessels (I wasn't aware that they were included to begin with), and I developed my own style of rockets. If I hadn't, I might be making Kerbal-X-looking designs today. Plus, users might end up learning the flaws as 'features'...

Radial stages with a higher likelihood of colliding is not a bug, but a consequence of the aerodynamics being tweaked. Calling something a bug just because it doesn't perform how you like it does not make it a bug. A flaw in the rocket's construction, yes. When the stock craft were first introduced in the respective updates, they were actually ideal for the game mechanics at that time. You could actually do a lot with Kerbal X, and it has actually been upgraded a couple of times. However, since the physics got an upgrade with planes in mind, that has changed how stages behave when they are ejected radially. Taking the time to improve Kerbal X yourself to work better falls well within the parameters of the game, and does help you learn a bit more of how a rocket performs. I would actually prefer the stock craft remain flawed as they are, as they are certainly not doing anybody in career or science mode any harm, at least until all the parts get researched so the entire craft can become mission-capable. In sandbox mode you are just tinkering with all the parts anyway, so you would either be in the camp that wants to tinker with the stock ships, or in the camp that doesn't. Either case, there is no harm in them being around just as they are.

Edited January 11, 2015 by samstarman5

[Reactordrone]

Kerbal X has actually been Mun-capable from its introduction. What it is not capable of as it is currently built, is returning back. Even Scott Manley has not managed that feat.

It's not impossible, I used to bullseye womprats in my T-16 back home....oh, I mean I just did it then. Granted it's the only time out of a number of attempts that I haven't had to get out and push and I did pull off a near perfect suicide burn but I still had 46m/s delta V left after the burn back to Kerbin.

[Scarecrow88]

There was another thread recently asking if the Kerbal X was now capable of getting to the Mun as the originator of that thread was struggling to even get it to LKO. As I've not flown the Kerbal X (or any stock craft) for some time, given how bad most of them are, I thought I would give it another go, just a couple of days ago. The best I could manage was a landing on Mun, followed by take off, but not enough fuel to re-establish Munar orbit. I know I am not the best pilot in KSP, but neither am I the worst. I'm still playing 0.25, so I don't know if that makes any difference, but I would say that the Kerbal X is still not Mun friendly for a new player.

[cantab]

Yeah, I thought it was reasonably well-known that the Kerbal X was now capable of a Mun return. I don't think it should be really.

I think the stock craft are worth having. The full part range in the VAB in Sandbox can be very daunting. I also think that they shouldn't give you ideal performance on a plate, hence the flaws. The Kerbal X was originally a rocket overengineered for reaching orbit - useful since it will soak up bad flying and/or let you mess around with manouvres. The ability to strand your Kerbals on the Mun was a funny perk. Now the engine buffs have made it capable of getting back, it doesn't feel quite right.

The one I used most though was the Aeris 3A, because I wanted to fly planes but was rubbish at building them.

And bear in mind, of course, that most of the stock craft are to support scenarios. Having them in regular saves is a side benefit.

[Archgeek]

Radial stages with a higher likelihood of colliding is not a bug, but a consequence of the aerodynamics being tweaked. Calling something a bug just because it doesn't perform how you like it does not make it a bug. A flaw in the rocket's construction, yes.

...

However, since the physics got an upgrade with planes in mind, that has changed how stages behave when they are ejected radially.

Actually, that issue very much is a bug. In the course of looking up a different decoupling bug (Kerbodyne decouplers only wanting to fire one at a time), I came across a discussion regarding the weird inward pivot in question, and it turns out it's a case of certain forces winding up inbalanced (in such a way that stronger decouplers actually make it worse) anytime a radial stage is dumped below the altitude that Kraken'sBane kicks in. I think it was related to the fix for decoupling stages that had been joined with struts.

[Whirligig Girl]

During beta they definitely need to redo some of the older stock craft, because the Kerbal X is OP for what it's supposed to be. It (and other stock craft) are supposed to be "Almost Good". The Kerbal X is just good.

Honestly I think the Mainsail is just too efficient now, you shouldn't be able to make such a small Mun rocket with rocket engines like the Mainsail. I'd prefer if they were made to have a 275 Isp in sea level. This is higher than it used to be, and the Vacuum Isp can stay the same as it is now as well.

[Renegrade]

Kerbal X has actually been Mun-capable from its introduction. What it is not capable of as it is currently built, is returning back. Even Scott Manley has not managed that feat.

Uh, see my album above for a FULL Kerbal X mun mission. There and back again. Kashua and some others did it too in the same thread; this came up (and I made this album) when 0.24 was released.

(Just because Mr Manley can't do something doesn't mean it can't be done, FYI. Also I'd be surprised if he couldn't do it.)

Radial stages with a higher likelihood of colliding is not a bug, but a consequence of the aerodynamics being tweaked. Calling something a bug just because it doesn't perform how you like it does not make it a bug.

Anchored Decoupler Fix.

Radial decouplers causing huge torques in the object being decoupled is a well established 0.24+ bug. This torque (er, moment of force) is always smashing the nose of the booster into the rocket, even when it shouldn't.

Here's a diagram of what happens:

The red arrow is the moment of force. The yellow/black circle is a really awful COM indicator for the side booster. The blue square is the decoupler location.

In part A, the decoupler is below the CoM causing torque in the direction indicated. This is the correct behavior (although in 0.24+, if you're traveling at high speed, but below the krakenbane system's activation speed (750m/sec if I recall correctly), the magnitude of this force is insanely high).

In part B, the decoupler is moved up, above the CoM, and yet the torque hasn't changed direction! (also it's magnitude is also violently, stupidly wrong at speed). The moment should be around the CoM in the opposite direction.

Note also that in real physics, the closer the decoupler is to the CoM, the less torque there will be, until it's aligned perfectly under the CoM (at which point the torque is zero).

Also note that stock aerodynamics are terrible ; most objects generate no torque regardless of orientation in airflow. KSP still does not model non-wing surface area at all. Nor have there been any significant updates to physics, aero or otherwise, save for some minor underlying Unity 'fixes'. *cough*whichmadethingsworse*cough*

Anyhow, in the Kerbal X design, the decouplers are mounted rather low-ish, but since those are LFBs, the CoM is going to be low too, near the decoupler. In the worst case scenario, it will still be a bit above the decoupler, which would result in GENTLE inward torque.. not the violent smashing that you see in unfixed stock.

UPDATE: I've actually tested the Kerbal X in a pure stock game on the launchpad, and my statement above holds. The LFB's center of mass is just slightly above the decoupler, causing only the faintest 'inwards' torque on the launchpad. An empty booster being ejected does not touch the core at any point. If you launch and get up to speed, they suddenly start turning in more and more violently, touching and exploding. Put in Claw's AnchoredDecoupler fix, and the problem goes away, letting them fall cleanly away before turning enough to touch the core.

(NB: Decoupling FULL boosters would be another thing entirely, since the CoM is a lot higher)

I would actually prefer the stock craft remain flawed as they are, as they are certainly not doing anybody in career or science mode any harm, at least until all the parts get researched so the entire craft can become mission-capable.

To be clear: I'm in favor of removing them, as I don't see the limited benefits they have as outweighing the major risk of teaching people bad habits.

To be fair, I may be overreacting because of the awfulness of the designs (Kerbal 2? What the HECK is this thing!?!).

[cantab]

Kerbal 2? What the HECK is this thing!?!

The Kerbal 2 was built as a 'trainer' rocket. It's not meant to reach very far, but it does feature most of the important systems found in the larger vessels.

Yes it has way too much monopropellant and an excessive engine, but it still does the job of letting you familiarise yourself with the game controls. It's not meant for anything more that that.

[Renegrade]

Yes it has way too much monopropellant and an excessive engine, but it still does the job of letting you familiarise yourself with the game controls. It's not meant for anything more that that.

...and it has fins and a large reaction wheel ON TOP of the already overpowered wheel in the cockpit, and movable tailfins on top of that.

I did a quick redesign of it, I swapped out well, everything below the decoupler, put on an 8t rockomax tank, the skipper, some of the smaller monoprop tanks, and moved the RCS quads a bit so they're between the CoM and DCoM. Now it flies for a lot longer (what, about 9x as long?), you can play with the reaction wheels for longer, and there's a chance the RCS could actually run out before you crash. It's still sub-orbital and has all the same toys and is just as useless, only it lets you play for a lot longer.

Also... the last thing people need to be learning is to put reaction wheels into tiny ships, given how massively overpowered cockpit reaction wheels are...

[metl]

I put reaction wheels on everything. They work. They allow for fine control when trying to land without adding the extra complication of balancing RCS, until I am ready to begin docking missions.

As far as the stock craft, they always seemed a waste. Honestly I never considered them lacking for a specific reason, I just assumed whoever built the stock craft sucked at the game, even though he was the one making the game (paradox?) My personal feelings is that they craft should be capable of performing basic feats for those learning the game to be able to use as a reference. I avoided building anything that looked like the X for a long time because I knew it didn't work. It made learning the game that much more difficult for me because I did not have working examples of how to accomplish what I wanted to accomplish. If the X would have been able to do a Mun landing and return, I would have understood much sooner some of the little nuances of the whole process.

[Renegrade]

I put reaction wheels on everything. They work. They allow for fine control when trying to land without adding the extra complication of balancing RCS, until I am ready to begin docking missions.

Note that they're excessively overpowered and entirely unrealistic (ie un-authentic). I'd go into details but it's been beaten to death already on this very forum. Also, learning to build around weaker wheels (like the internal ones) will stand you in good stead should you happen across RO or BTSM or Stock Rebalance or such.

I just assumed whoever built the stock craft sucked at the game, even though he was the one making the game (paradox?)

That was my initial assumption as well (that's not really a paradox, btw).

[Overfloater]

The craft has always been Minmus capable, so it was ""overpowered'''' even back then! Because it was very good at it, there was plenty of error margin and ability to jump around on minmus and then safely return.

Let's give the Mainsail 150 isp, just to be sure...