Landing super heavy landers.

[rottielover]

So now that I've been playing KSP for several weeks, I started getting into all the cool mods. Besides the core mechjeb and alarm clock, I picked up KAS, Kethane, and ISA MapSat.

I've been really getting into the Kethane mod, and built some simple small robotic landers that drill and refine Kethane into usable fuel.

Unfortunately that's all those designs do. (It's a little like the Mars concept mission, send a robot to make fuel for the return trip).

Anyway, I've seen screenshots of people using "trucks" and "mining rigs". So I designed my own modular "trucks" to drill and store Kethane (still working on what I'm going to do about a refinery.).

So my heavy drilling rig (mechjeb) reports to weight in at 25 tons. Not only that but I built it "sideways" in the VAB. (Sorry I'm still pretty noobish at this point).

I have some super heavy lifters, so orbit and transfer are no problem, landing these things without smashing into atomic particles, is a problem.

Most of the designs I have stuck in my head right now would put the truck at the top, so once it's landed I can't get it down to the surface.

If I try and build a huge skycrane, well that's just not gone very well at all....

It's one thing to land a cylander upright on some legs, it's totally another beast to land a sideways cylander with a "this way up" sign on it, correctly.

Apologies for the long explanations, figured the more info I could spew into this the better.

Edited July 13, 2013 by rottielover

[stupid_chris]

Could you provide screenshots? Those are really helpful in this kind of situation. Also, if you were to give out a craft file, I could probably give you an example of how to land it.

Anyway, there are several ways of landing rovers. The most commonly used ones are skycranes I must say. But you can also build a lander around it. Building the launcher above it though is harder to use with larger rovers. Again, a screenshot would be the best to help you.

[NoMrBond]

Get the thrust laid out properly under/around your load (CoM) [Removed; Guitar man violation] and you can land anything.

If you want your landing rig to come off after landing, then you can probably attach it to the sides of your truck with radial decouplers

Or you can keep your lateral engines for hijinks after you've used them for landing

Either way, make sure that you position your engines taking note of the Center-of-Mass/Thrust so you don't end up getting the descent flips/death-spiral

Edited July 11, 2013 by NoMrBond

[rottielover]

Point taken, I'll grab screen shots and see about posting up a craft file(s).

[NoMrBond]

The Engineer Redux is also good to make sure your rig has enough thrust for where so ever you're landing it, this will let you check your Mün rig has at least TWR of 1 at the Mün, and so on for the other planets (unless you can additionally use 'chutes for bodies with atmosphere)

[Edit]

Balancing load and rocket positions so CoT is below CoM

TWR seems really high, when it's empty, I'm pitching that when it's got 16K of Kethane on board that'll be a lot more reasonable

Edited July 11, 2013 by NoMrBond

[rottielover]

Well here goes, I just signed up for Dropbox so I hope this works.

https://www.dropbox.com/sh/wqo76c3tc1zuora/7AWjA3kUdl

That is a folder that has a screenshot and two craft files.

One craft is the driller / tanker, the other is my "power truck".

The idea is that I can hookup a few drilling rigs to the power truck if they need to drill in the dark.

**** Mods Needed ****

MechJeb, KAS, Kethane, Quantum Stuts (possibly KSPX can't remember)

Btw- the quantum struts are on the power truck to keep it from flexing under its own weight. I tried to do this with normal struts and I beams but it didn't work. I'd prefer not to use quantum struts if possible.

There is a probe core mounted to the top for ease of "control from here" driving (couldn't figure out how to get the other command piece to drive correctly). I'd like to know if that's fixable?

These are Alpha POC (proof of concept) designs, please be kind with feedback.

Edited July 11, 2013 by rottielover
missed a mod needed

[rottielover]

Also: after further reading I'm going to redesign the wheels a bit to lower the center of mass down. Originally I had been thinking about ground clearance, but that doesn't seem to be as much of a concern as tipping over.

[Eric S]

Also: after further reading I'm going to redesign the wheels a bit to lower the center of mass down. Originally I had been thinking about ground clearance, but that doesn't seem to be as much of a concern as tipping over.

Ground clearance may become a bit more of an issue with the procedural craters, emphasis on may.

[stupid_chris]

Alright I'll take a look ASAP

[stupid_chris]

Alright, I put together (very quickly) an example skycrane for one of your rovers.

It has about 1450m/s of delta V and a good TWR. I didn't know exactly where you wanted to land, but it probably covers it. I'll include a download link so you can look at it and deconstruct it and try things like this yourself. You can add chutes, fuel tanks, engines, an apple pie, I don't know. It's always best to suit your lander for where you are going when dealing with large payloads.

Oh and symmetry was really weird with it, idk exactly what your root part was, but it'S always better to keep it vertical not to mess up symmetry. Building rovers in the SPH and then transferring them to the VAB for launch is also generally easier.

If you have any more questions, feel free to ask!

Download

[blizzy78]

I built myself a craft that I constantly use to launch and land things on Ike: Spider HULL Mk 3

I also have a few variants like a smaller one with weaker engines, or a tri-engine one for special base modules I use. Those variants are not on Spaceport, though.

Edited July 12, 2013 by blizzy78

[elkar]

I was using skyscrane design for Kerbin system all the time, but sometimes its really better to use lander with its own landing power.

[rottielover]

Chris, Really appreciate it!

I'll try the move craft file trick next time. I built it in the VAB horizontally and had to place each part individually.

If I recall correctly the root part was the large (rock o max) sized remote probe core then I built from there.

Obviously I'm still very new at this game, I've been getting around (rovers) by borrowing others designs, (sometimes I modify them), and doing my mission. These rovers were my first attempt at building my own design from scratch.

Rockets and spacecraft and basic landers I can do, but for some reason rovers have confounded me.

I plan to pick apart your design to learn from it.

Again, I really appreciate you taking the time to help me out!!

One of the reasons I love this game, the community base has been one of the best of all time for any game.

[rottielover]

Blizzy, thanks for sharing that! Looks very interesting, I def want to try that one out as well!!

One of my goals in my designs is to make them easily controllable. I feel my designs should work equally well if you fly/drive them manually or if you choose to use MechJeb. I've learned a lot from you all and I appreciate it!

[blizzy78]

No problem, let me know how it goes or if anything can be improved.

[stupid_chris]

No problem here too

And I'm gonna do a bit of self promoting, but if you never need help building something or there's something you wanna do but just can't get a good idea to put it together, just give me a shoutout in my thread (link in sig), it'll be my pleasure to help you

[rottielover]

OK, i'm feeling stupid, how do I mark this thread as answered?

[stupid_chris]

OK, i'm feeling stupid, how do I mark this thread as answered?

I think you can change it via the advanced editor on the OP, else it's only a moderator that can change it.

[rottielover]

I think you can change it via the advanced editor on the OP, else it's only a moderator that can change it.

Yep, thank you again! For future reference for anyone else: Go to your opening post, edit it, click "go advanced" and you'll see the drop down!

[rottielover]

Quick update: I mated Chris's skycrane version to the lifter stage of the MOLAB super rover (posted in the share ships section). I had to add fuel lines (a few were missing, later I changed the 2nd stage to gimbal engines.

After 4 hours of testing and trial and error, I was almost ready to scrap the whole project. Problem- almost no torque control and RCS was running out of mono turning this thing. So I overkilled it and added 4 of the large mono tanks and added 16 radial mono tanks to the crawler itself.

It was overkill on mono, but it did finally allow me to get the thing set down on the mun, only 2 km off target to boot. But I ran out of biprop in the skycrane and landed hard, and with the skycrane still attached. When I tried to drive away the wheels weren't working. I right clicked and found all 4 wheels as "Status: Broken".

So by that time I went to bed. I hope to get more play time today in order to work on the design more.

[stupid_chris]

Well, indeed overkill on the monopropellant xD Maybe a half KSPX tank would do the job. Uhg, .21 where are you, I WANT THOSE REACTION WHEELS.

[rottielover]

Ya originally I tried slapping on more and more octo2 probe cores, but that didn't seem to make any differance. So I started working on the reaction system.

I think what I'm going to do is re-build the design starting with a small probe core in the middle, maybe that will eliminate all the odd issues I'm getting in the VAB with this build.

[stupid_chris]

You could add empty command pods, they give off much more torque

[rottielover]

Ya, ever since I downloaded this escape pod mod (awesome mod btw) I've been thinking about a "Multiple launch Escape Pod System". The "mod pod" is a single seater, but includes all its own systems (RCS, engines, etc). So maybe this will be my excuse to come up with that "MLEPS" and tack it on for control of my trucks.

I did take the time today to rebuild the truck from scratch and I am much happier with the results. Thanks to Temstar, I picked up his pack of launchers and tacked on his Zenith VII. I'm still working out the kinks though because the zenith VII and my 2nd stage are not getting along (ie the rocket explodes upon leaving Kerbin's atmosphere (always fails at the same decoupler no matter how many struts.

So I have a little work to do on it.

[stupid_chris]

The SpaceTech escape pod is nice indeed. Glad to know you're making progress! If you wanna learn, you can try taking aparpt Temstar'S rockets. They're tad bit more complex than normal, but they're a really good model to build future rockets off.