Strange Forces on Craft

[JackDugan]

I was testing an Eve lander that I've been working on and some phantom forces spun my craft. I even turned off electricity, yet it still occurs. It appears to be the craft spinning itself because, as the pictures show, there is a constant torque on the craft. The main issue is that this torque rips the craft apart during liftoff on Eve because the craft turns when I turn SAS off while going extremely fast low in the atmosphere. When SAS is on, the torque is not applied. Is there any idea on what this could be (besides the Kraken)? Note that I uninstalled Hyperedit and rebooted KSP and was still affected. Also, I played earlier with Hyperedit but without this issue.

 

[kiwi1960]

Something similar happened in the KSPTV 1,1 video today... EJ went to minmus where he had 3 super ships landed, and as he was watching, they started to spin and drop bits and explode.... that is 1.1 ... nothing much has changed it seems.

 

[Anquietas314]

Looking at the pictures, it seems your struts and fuel lines are not placed very neatly - that can cause these sorts of "phantom" forces; this should also happen on Kerbin if you launched the craft as-is, though perhaps it will be less noticeable. Normally SAS can overpower those forces. Basically the issue is struts and fuel lines contribute to the aerodynamics of the craft. Also if the engines are strong enough, the ship could deform in a way that creates an asymmetry in the thrust applied by the engines, which can create torque too. Same idea goes for lift from wings as well as drag. You'll see this kind of thing a lot with asparagus staging. To fix it, just be very careful when placing struts and fuel lines to get them as symmetrical as possible, and for this particular lander just use SAS on the ascent .

8 hours ago, kiwi1960 said:

Something similar happened in the KSPTV 1,1 video today... EJ went to minmus where he had 3 super ships landed, and as he was watching, they started to spin and drop bits and explode.... that is 1.1 ... nothing much has changed it seems.

That appears to be a bug in 1.1 with multiple sets of connected docking ports and is almost certainly not related - similar bugs have appeared in previous versions.

[kiwi1960]

They are related if you consider both versions are in KSP. The fact that its appeared in other versions and is still with us is proof of that.

[Anquietas314]

4 minutes ago, kiwi1960 said:

They are related if you consider both versions are in KSP. The fact that its appeared in other versions and is still with us is proof of that.

They're unrelated in the sense that the cause is two entirely separate things - in the case of the 1.1 issue, a bug with docking ports that doesn't exist in 1.0.5; in the case of the issue OP is experiencing, (presumably) intended behaviour of struts, fuel lines etc; metal beams and tubes sticking out randomly would affect things in real life too.

[kiwi1960]

56 minutes ago, armagheddonsgw said:

They're unrelated in the sense that the cause is two entirely separate things - in the case of the 1.1 issue, a bug with docking ports that doesn't exist in 1.0.5; in the case of the issue OP is experiencing, (presumably) intended behaviour of struts, fuel lines etc; metal beams and tubes sticking out randomly would affect things in real life too.

I know what you are saying, but they are related by KSP, meaning... the bug MUST be some of the coding.... especially if its across so many versions.

Or rather... the bug COULD be blamed on UNITY .... both 4 and 5 ... either way, its sad to see those bugs still there.

[Anquietas314]

7 minutes ago, kiwi1960 said:

I know what you are saying, but they are related by KSP, meaning... the bug MUST be some of the coding.... especially if its across so many versions.

Or rather... the bug COULD be blamed on UNITY .... both 4 and 5 ... either way, its sad to see those bugs still there.

You're missing the point. OP's issue is, as far as I know, not a bug, it's a design problem with the craft (edit: in the same way sticking fins on at the wrong angle out of carelessness is not a bug), and to some degree a lack of tools in the editor (e.g. can't angle-snap the other end of a strut), which I wouldn't consider a bug.

Edited March 27, 2016 by armagheddonsgw

[kiwi1960]

58 minutes ago, armagheddonsgw said:

You're missing the point. OP's issue is, as far as I know, not a bug, it's a design problem with the craft (edit: in the same way sticking fins on at the wrong angle out of carelessness is not a bug), and to some degree a lack of tools in the editor (e.g. can't angle-snap the other end of a strut), which I wouldn't consider a bug.

Then surely.... its a bug.... given what you said. If a person can edit any craft he wants, BUT... the game reacts badly to that edit... then its a problem with the game, not the designed of the game. Most games have limits to prevent such bugs, but not in KSP, which means its allowed... but if its allowed... and it ends badly, then... its a bug.

However... we shall agree to disagree rather than go round in circles.

[Anquietas314]

19 minutes ago, kiwi1960 said:

If a person can edit any craft he wants, BUT... the game reacts badly to that edit... then its a problem with the game, not the designed of the game.

It would be a bug if the game crashed, or if for example there were phantom forces with struts inside a fairing or closed cargo bay (that should not influence the flight e.g. due to structural warping), or if Squad do not intend struts and fuel lines to influence either the aerodynamics or the structural properties of a ship (the last part is clearly not the case - the entire purpose of struts is to strengthen and increase the rigidity of ships, and fuel lines perform the same role to a lesser degree).

In this case there's a physically based explanation of the forces and torque being applied, and that explanation would also apply in the real world. Unless stated otherwise by Squad, it's not a bug. You could argue that the fact you can't angle-snap the other end of struts and fuel lines is a design flaw, but for the moment it's the intended behaviour, so again it's not a bug (key factor being intended behaviour).

OP's issue is a design problem with the craft, not the game (mostly - angle snap would be nice).

27 minutes ago, kiwi1960 said:

However... we shall agree to disagree rather than go round in circles.

I agree that there's little point on arguing over the same point if neither side is willing to concede any ground.

[kiwi1960]

1 minute ago, armagheddonsgw said:

II agree that there's little point on arguing over the same point if neither side is willing to concede any ground.

At least we are wise enough to agree on that point. Its not that we are unwilling to concede ground, but really, I suspect we are both right to a degree. We merely need to work out what that degree is. But... it is enough that we agree to disagree.