Ruggedized Wheel Problems

[Zosma Procyon]

I'm having a problem with my new mobile base. When loaded onto the launch pad or runway, it bounces/shimmies until the TR-2L ruggerized wheels break, or in a few cases the launch pad explodes. The base masses 46.5 tons, and there are 40 wheels in 4 banks of 10. Pictures below of the the base and the wheels. I have another similar mobile base with the same wheel arrangement that does not bounce until it explodes. All of the parts are autostruted to the heaviest part and rigidly connected, as they are on my base that does not self destruct. Does anyone have any ideas of what is wrong?

Edited November 30, 2017 by Zosma Procyon

[Corona688]

Perhaps if you set it down wheels first...

...j/k, the wheels look too close together to me, both horizontally and lengthwise.

Edited November 30, 2017 by Corona688

[KerikBalm]

13 hours ago, Zosma Procyon said:

All of the parts are autostruted to the heaviest part and rigidly connected,

Try not using autostrut on the rest of the base. I've found excessive use of part autostrut summons a kraken and can cause a craft to shake itself apart. In many cases, removing some autostruts fixed the problems for me

[softweir]

Moved to Gameplay Questions by your Friendly Neighbourhood Moderator.

[Zosma Procyon]

6 hours ago, KerikBalm said:

Try not using autostrut on the rest of the base. I've found excessive use of part autostrut summons a kraken and can cause a craft to shake itself apart. In many cases, removing some autostruts fixed the problems for me

No joy. The wheels broke immediately.

[Zosma Procyon]

8 hours ago, Corona688 said:

Perhaps if you set it down wheels first...

...j/k, the wheels look too close together to me, both horizontally and lengthwise.

This is what happened when I moved the pontoons the wheels are mounted on apart one half notch.

Notice it destroyed the pad.

And this is what happens when i revert to launch without the unbreakable joints cheat enabled.

I'm going to play around with my original mobile base, in which everything is autostructed and worked well enough I already tested it on the Mun. Worked great until I took a turn to tight and rolled with cheats turned off. BOOM.

This is it landing.

And here it is in the VAB.

Other than the different command pod, the only substantive differences are the original has 12 front wheels instead of 20, and the internal (hidden from view) small storage tanks are attached differently. In the original the they are arranged radially around an I-beam that connects the two halves of the crawler, where as in the troubled new version that are attached to the battery at the nadir of the front half.

Edited November 30, 2017 by Zosma Procyon

[Plusck]

Well, I tried a few variations with large numbers of ruggedized wheels (more than your example), and I still haven't managed to blow up my ship. I used the SPH and I mostly didn't use autostrut, but I tried autostrut on a number of parts and it didn't make any difference.

However, there are a few things that I noticed as I was trying to copy some of the features of your build:

• radial attachment: the wheels bug out in the editor when taking a perfectly acceptable bogey built via node attachment and then trying to attach it to a radially attached part. Specifically, taking a node-attached tank + wheels and moving it to a radially-attached part made the wheels switch to radial symmetry (but not the rest of the tank or other parts attached to it. Pic below. This may indicate a source of problems... but still once I finally got the wheels right it didn't explode or anything.
• crew cabins: crew cabins can't be attached radially. Therefore in that last pic (not the one that doesn't work, oddly...) the front sets of wheels must be attached through the nosecone. This has to be weak. But the game didn't object to that one, so that's odd.
• ore tanks: you should never use ore tanks to support any significant weight. Their structure is extremely weak, whether attached radially or by nodes, far weaker than fuel tanks. It looks like the backbone of your craft is made up of a series of 1.25m ore tanks. This is asking for trouble.
• or instead, did you node-attach the cockpit and 4-man crew cabin, then offset them? This would also be weak, but I tried doing just that and had no serious issues either. [edit: rereading your last post, no, you didn't do this. But you are using ore tanks as backbone, which is not going to help]
• clipping: I didnt try to reproduce it but you have a lot of parts clipped in. However, I can't see anything that would really cause a problem with clipping.
• balance: I can't see what is on the other side from the drills, but it certainly can't be balanced.

Spoiler

Odd editor behaviour. The battery and panels are in the right place for mirror symmetry. The wheels however are put on radial symmetry when I place the tank. Very odd.

But still, despite my best efforts, there is no real problem on the runway:

 

So, sorry I can't really help.

Could it simply be part count that is causing the problem?

 

Edit 2:

Hang on a second...

Judging by the way your craft fell apart on the launchpad, you have attached one modular girder to the surface of the fuel tank, then put wheels on it, then attached a series of them by node attachment the length of each section. If you do this, you really have to make the middle set of wheels the first ones that you surface attach, otherwise you're creating a long lever arm of girders to support the weight of the craft. Remember that when you surface attach a line of objects, only the first part will actually be attached. The rest of the parts are clipped but there is no structural strength there.

Also, to get the spacing of the wheels, your surface attachments have to be only just touching (or not really touching) the 2.5m parts which are a science lab and a hitchhiker can.

I just tried this out. Attaching radially and offset slightly from the science lab was ok. Not ok was when I tried to do the same with the hitchhiker can. It didn't explode, but it was jumpy and not happy. That may well be what is causing your craft to fall apart.

Edited December 1, 2017 by Plusck

[Zosma Procyon]

52 minutes ago, Plusck said:

Well, I tried a few variations with large numbers of ruggedized wheels (more than your example), and I still haven't managed to blow up my ship. I used the SPH and I mostly didn't use autostrut, but I tried autostrut on a number of parts and it didn't make any difference.

However, there are a few things that I noticed as I was trying to copy some of the features of your build:

• radial attachment: the wheels bug out in the editor when taking a perfectly acceptable bogey built via node attachment and then trying to attach it to a radially attached part. Specifically, taking a node-attached tank + wheels and moving it to a radially-attached part made the wheels switch to radial symmetry (but not the rest of the tank or other parts attached to it. Pic below. This may indicate a source of problems... but still once I finally got the wheels right it didn't explode or anything.
• crew cabins: crew cabins can't be attached radially. Therefore in that last pic (not the one that doesn't work, oddly...) the front sets of wheels must be attached through the nosecone. This has to be weak. But the game didn't object to that one, so that's odd.
• ore tanks: you should never use ore tanks to support any significant weight. Their structure is extremely weak, whether attached radially or by nodes, far weaker than fuel tanks. It looks like the backbone of your craft is made up of a series of 1.25m ore tanks. This is asking for trouble.
• or instead, did you node-attach the cockpit and 4-man crew cabin, then offset them? This would also be weak, but I tried doing just that and had no serious issues either. [edit: rereading your last post, no, you didn't do this. But you are using ore tanks as backbone, which is not going to help]
• clipping: I didnt try to reproduce it but you have a lot of parts clipped in. However, I can't see anything that would really cause a problem with clipping.
• balance: I can't see what is on the other side from the drills, but it certainly can't be balanced.

  Hide contents

Odd editor behaviour. The battery and panels are in the right place for mirror symmetry. The wheels however are put on radial symmetry when I place the tank. Very odd.

But still, despite my best efforts, there is no real problem on the runway:

 

So, sorry I can't really help.

Could it simply be part count that is causing the problem?

 

Edit 2:

Hang on a second...

Judging by the way your craft fell apart on the launchpad, you have attached one modular girder to the surface of the fuel tank, then put wheels on it, then attached a series of them by node attachment the length of each section. If you do this, you really have to make the middle set of wheels the first ones that you surface attach, otherwise you're creating a long lever arm of girders to support the weight of the craft. Remember that when you surface attach a line of objects, only the first part will actually be attached. The rest of the parts are clipped but there is no structural strength there.

Also, to get the spacing of the wheels, your surface attachments have to be only just touching (or not really touching) the 2.5m parts which are a science lab and a hitchhiker can.

I just tried this out. Attaching radially and offset slightly from the science lab was ok. Not ok was when I tried to do the same with the hitchhiker can. It didn't explode, but it was jumpy and not happy. That may well be what is causing your craft to fall apart.

The one that works has more parts that the one that keeps freaking out. Anyway I like having a bit more ground clearance. I'm actually trying to make one with the pontoons attacked at the end of short I-beams, of course they keep exploding. Anyway I will answer your points.

None of the wheels, cabins, box girders, or I beams are radially attached.

The crew cabins in the pontoons are connected via struts to both the box girders and the main body of the base.

The ore tanks do not hold any weight in this. The top middle cockpit and are attached to the battery in front of them, offset upwards, The tanks are radially attached around a central I-Beam connecting the two halves, and are in no way load bearing parts. They are offset to be partially inside each half. That might be why the second version keeps exploding?

On the other side of the drills are 4 of the materials science junior things, with round nose cones stuck to their underside. That isn't as much mass as the drills, but it's pretty close.

I don't know if offseting the hitchiker cabin from the lab can actually get the distance I want. I'll try. But my method of connecting via an I-beam works in at least one vehicle. I wonder if I invented a new kraken. The second version does not develop either explody or shaky problems until all of the wheels are attached.

[Zosma Procyon]

2 hours ago, Plusck said:

Well, I tried a few variations with large numbers of ruggedized wheels (more than your example), and I still haven't managed to blow up my ship. I used the SPH and I mostly didn't use autostrut, but I tried autostrut on a number of parts and it didn't make any difference.

However, there are a few things that I noticed as I was trying to copy some of the features of your build:

• radial attachment: the wheels bug out in the editor when taking a perfectly acceptable bogey built via node attachment and then trying to attach it to a radially attached part. Specifically, taking a node-attached tank + wheels and moving it to a radially-attached part made the wheels switch to radial symmetry (but not the rest of the tank or other parts attached to it. Pic below. This may indicate a source of problems... but still once I finally got the wheels right it didn't explode or anything.
• crew cabins: crew cabins can't be attached radially. Therefore in that last pic (not the one that doesn't work, oddly...) the front sets of wheels must be attached through the nosecone. This has to be weak. But the game didn't object to that one, so that's odd.
• ore tanks: you should never use ore tanks to support any significant weight. Their structure is extremely weak, whether attached radially or by nodes, far weaker than fuel tanks. It looks like the backbone of your craft is made up of a series of 1.25m ore tanks. This is asking for trouble.
• or instead, did you node-attach the cockpit and 4-man crew cabin, then offset them? This would also be weak, but I tried doing just that and had no serious issues either. [edit: rereading your last post, no, you didn't do this. But you are using ore tanks as backbone, which is not going to help]
• clipping: I didnt try to reproduce it but you have a lot of parts clipped in. However, I can't see anything that would really cause a problem with clipping.
• balance: I can't see what is on the other side from the drills, but it certainly can't be balanced.

  Reveal hidden contents

Odd editor behaviour. The battery and panels are in the right place for mirror symmetry. The wheels however are put on radial symmetry when I place the tank. Very odd.

But still, despite my best efforts, there is no real problem on the runway:

 

So, sorry I can't really help.

Could it simply be part count that is causing the problem?

 

Edit 2:

Hang on a second...

Judging by the way your craft fell apart on the launchpad, you have attached one modular girder to the surface of the fuel tank, then put wheels on it, then attached a series of them by node attachment the length of each section. If you do this, you really have to make the middle set of wheels the first ones that you surface attach, otherwise you're creating a long lever arm of girders to support the weight of the craft. Remember that when you surface attach a line of objects, only the first part will actually be attached. The rest of the parts are clipped but there is no structural strength there.

Also, to get the spacing of the wheels, your surface attachments have to be only just touching (or not really touching) the 2.5m parts which are a science lab and a hitchhiker can.

I just tried this out. Attaching radially and offset slightly from the science lab was ok. Not ok was when I tried to do the same with the hitchhiker can. It didn't explode, but it was jumpy and not happy. That may well be what is causing your craft to fall apart.

I'm working on another version that only autostructs a few parts.

No boom. Drove it around awhile, then tried to ram the VAB.

It esploded. Killed the driver. Good thing you can reset.

[Zosma Procyon]

2 hours ago, Plusck said:

Well, I tried a few variations with large numbers of ruggedized wheels (more than your example), and I still haven't managed to blow up my ship. I used the SPH and I mostly didn't use autostrut, but I tried autostrut on a number of parts and it didn't make any difference.

However, there are a few things that I noticed as I was trying to copy some of the features of your build:

• radial attachment: the wheels bug out in the editor when taking a perfectly acceptable bogey built via node attachment and then trying to attach it to a radially attached part. Specifically, taking a node-attached tank + wheels and moving it to a radially-attached part made the wheels switch to radial symmetry (but not the rest of the tank or other parts attached to it. Pic below. This may indicate a source of problems... but still once I finally got the wheels right it didn't explode or anything.
• crew cabins: crew cabins can't be attached radially. Therefore in that last pic (not the one that doesn't work, oddly...) the front sets of wheels must be attached through the nosecone. This has to be weak. But the game didn't object to that one, so that's odd.
• ore tanks: you should never use ore tanks to support any significant weight. Their structure is extremely weak, whether attached radially or by nodes, far weaker than fuel tanks. It looks like the backbone of your craft is made up of a series of 1.25m ore tanks. This is asking for trouble.
• or instead, did you node-attach the cockpit and 4-man crew cabin, then offset them? This would also be weak, but I tried doing just that and had no serious issues either. [edit: rereading your last post, no, you didn't do this. But you are using ore tanks as backbone, which is not going to help]
• clipping: I didnt try to reproduce it but you have a lot of parts clipped in. However, I can't see anything that would really cause a problem with clipping.
• balance: I can't see what is on the other side from the drills, but it certainly can't be balanced.

  Reveal hidden contents

Odd editor behaviour. The battery and panels are in the right place for mirror symmetry. The wheels however are put on radial symmetry when I place the tank. Very odd.

But still, despite my best efforts, there is no real problem on the runway:

 

So, sorry I can't really help.

Could it simply be part count that is causing the problem?

 

Edit 2:

Hang on a second...

Judging by the way your craft fell apart on the launchpad, you have attached one modular girder to the surface of the fuel tank, then put wheels on it, then attached a series of them by node attachment the length of each section. If you do this, you really have to make the middle set of wheels the first ones that you surface attach, otherwise you're creating a long lever arm of girders to support the weight of the craft. Remember that when you surface attach a line of objects, only the first part will actually be attached. The rest of the parts are clipped but there is no structural strength there.

Also, to get the spacing of the wheels, your surface attachments have to be only just touching (or not really touching) the 2.5m parts which are a science lab and a hitchhiker can.

I just tried this out. Attaching radially and offset slightly from the science lab was ok. Not ok was when I tried to do the same with the hitchhiker can. It didn't explode, but it was jumpy and not happy. That may well be what is causing your craft to fall apart.

Through trial and error I seem to have found the problem. Excessive autostructing combined with maxing out the stats on the wheels. Now I'm going to test the theory.

[Plusck]

3 hours ago, Zosma Procyon said:

Through trial and error I seem to have found the problem. Excessive autostructing combined with maxing out the stats on the wheels. Now I'm going to test the theory.

Oh, cool.

I didn't think to change the stats on the wheels, which is a bit stupid since I've had jittery landers when I've gone overboard reinforcing legs.
As you can see from my tests, ruggedized wheels are fine on Kerbin supporting several tons each, so you definitely don't need to reinforce their stats for what you have them carrying on a moon.

As for the ore tanks: I don't quite follow your explanation there, and I suspect that this is a source of weakness. It sounds like you::

1. attached the mk2 cockpit to the node, and then the crew cabin to the exposed node
2. offset the cabin upwards to be flush with the 2.5m parts
3. attached an I-beam to the remaining exposed face of the 2.5m part
4. attached the next 2.5m part to the exposed node of the i-beam.

That means that the i-beam has one of its nodes surface-attached (at the front) and the other node is node-attached. I don't know if that is any weaker than node-attaching both ends (I did a quick test and could see no difference in flex when heavily loaded between the two options... see pic below). However it is certainly not good for KSP's aero model since the rear of the crew cabin is fully exposed to the airflow, as is the whole of the front of the next 2.5m part.

Still, it is certainly better than using ore tanks to hold the structure together. Clipping ore tanks shouldn't cause a problem.

However, instead of doing that, I would suggest attaching the 2.5m and Mk 2 parts all in a line, then offsetting the cockpit up to be flush and the following 2.5m part down to be flush, then reinforcing with a strut or two between the facing 2.5m parts. That way you don't have the crew cabin floating around while clipped in to the following 2.5m part. You can surface attach the ore tanks underneath the mk2 parts and nothing should budge.

Spoiler

i-beam node attached on the left. On the right, the small tank occupies the node and was then offset upwards, so the i-beam is attached to the surface. Can't see a difference...

 

[Zosma Procyon]

9 minutes ago, Plusck said:

Oh, cool.

I didn't think to change the stats on the wheels, which is a bit stupid since I've had jittery landers when I've gone overboard reinforcing legs.
As you can see from my tests, ruggedized wheels are fine on Kerbin supporting several tons each, so you definitely don't need to reinforce their stats for what you have them carrying on a moon.

As for the ore tanks: I don't quite follow your explanation there, and I suspect that this is a source of weakness. It sounds like you::

1. attached the mk2 cockpit to the node, and then the crew cabin to the exposed node
2. offset the cabin upwards to be flush with the 2.5m parts
3. attached an I-beam to the remaining exposed face of the 2.5m part
4. attached the next 2.5m part to the exposed node of the i-beam.

That means that the i-beam has one of its nodes surface-attached (at the front) and the other node is node-attached. I don't know if that is any weaker than node-attaching both ends (I did a quick test and could see no difference in flex when heavily loaded between the two options... see pic below). However it is certainly not good for KSP's aero model since the rear of the crew cabin is fully exposed to the airflow, as is the whole of the front of the next 2.5m part.

Still, it is certainly better than using ore tanks to hold the structure together. Clipping ore tanks shouldn't cause a problem.

However, instead of doing that, I would suggest attaching the 2.5m and Mk 2 parts all in a line, then offsetting the cockpit up to be flush and the following 2.5m part down to be flush, then reinforcing with a strut or two between the facing 2.5m parts. That way you don't have the crew cabin floating around while clipped in to the following 2.5m part. You can surface attach the ore tanks underneath the mk2 parts and nothing should budge.

  Reveal hidden contents

i-beam node attached on the left. On the right, the small tank occupies the node and was then offset upwards, so the i-beam is attached to the surface. Can't see a difference...

 

This is what I arrived at. I remembered that bases had to had viewing cupola, so found a place to stick them.

The CoM is a little further forward than I'd like, but I might add a fuel tank to the aft section. And it isn't fully kitted out yet. As is it will do 43 m/s in a dead sprint down the runway.

[Plusck]

Actually, I just rechecked and my first test wasn't loaded enough.

A surface-attached i-beam is weaker than node attachment, once you start putting some weight on it:

I-beam using the node attachment on the left. The small tank is occupying the node on the right.

In another test with the orange tanks mounted higher, the surface-attached beam wasn't able to withstand the twist and the tank ended up falling off.

Edited December 1, 2017 by Plusck

[Zosma Procyon]

Just now, Plusck said:

Actually, I just rechecked and my first test wasn't loaded enough.

A surface-attached i-beam is weaker than node attachment, once you start putting some weight on it:

I-beam using the node attachment on the left. The small tank is occupying the node on the right.

Yeah I used your strategy in my semi-final product. Still needs solar panels, radiators, fuel cells, NUKs, decent thusters, parachutes, and a massive rocket to carry it out to Duna. All easy stuff. Fun, fun, fun. Thank you everyone for your assistance in tackling this fastest kraken.