Something doesn't seem right here....

[Majorjim!]

This revelation isn't going to change the way I build things in the slightest.

Agreed. It is a small issue, easy to compensate for.

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I don't think struts should behave this way. Their effect seems way outsized.

Also agreed. The effect, although minor is way out of proportion to the size of the struts. They should have almost no drag at all or none entirely.

[Alien1099]

I don't think struts should behave this way. Their effect seems way outsized.

Yeah many times they're used as a compromise to make a ship rigid because of the wobblyness inherent in the game for craft that would never behave that way in real life.

[regex]

They should have almost no drag at all or none entirely.

Wires and cables produce drag IRL, struts should be no different. That value is certainly up for debate, especially since certain part occlusion isn't modeled in the stock aero (or oldFAR for that matter) and struts are often clipped inside the craft, but saying they shouldn't produce any drag at all is dodging a very real concern.

[RAINCRAFTER]

This thread is cool. Struts? Drag? Woah! Mass? Nyah!

The title is very correct.

[problemecium]

Hmm, so it was the strut...

I did raise a mental eyebrow (I can't figure out how to do it IRL xP) when I observed that previously "physics-less" parts such as batteries and Science instruments were actually affecting the drag and total dV of my ships. It seems like even with the new model, 1.0 would still perform better if these bits were still ignored by the simulation.

[Red Iron Crown]

This thread is cool. Struts? Drag? Woah! Mass? Nyah!

The title is very correct.

Struts have mass now, like all physicsless parts. The mass is added to the first physicsful parent part.

[r4pt0r]

Struts have mass now, like all physicsless parts. The mass is added to the first physicsful parent part.

I just want to clear up a personal question then. I wasnt sure how to word my question so here is a picture:

In the event that the struts mass isnt deleted, it would then stick to the parent part right?

[Red Iron Crown]

Only one of them keeps the mass, the one on which the strut was started.

[WinkAllKerb'']

when you place a strut in vab or sph second click disapear if strut linkage broke, only first click remain (and so the resulting no vectoring force applied split highlighted earlier in the thread as one of the strut side simply vanish)

Edited May 23, 2015 by WinkAllKerb''

[r4pt0r]

oh. so if you REALLY cared about efficiency, your struts would all start on the disposable parts.

interesting.

[Red Iron Crown]

oh. so if you REALLY cared about efficiency, your struts would all start on the disposable parts.

interesting.

Yes. It's the same deal with fuel lines, but there you don't really have a choice which part to start with.

[WinkAllKerb'']

non expected and counter intuitive asymetric results ... i just wonder if this is this a native unity only issue (i mean node, surf attach, "vectoring orient root/order" related) ?

Edited May 23, 2015 by WinkAllKerb''

[REMD]

Can someone make twin rocket test on Mun or on different atmosphere less planet/moon ? you know .. just for science

[Engineer of Stuff]

So the conclusion is, um, less struts is good? That does not sound right.

[Gargamel]

For aesthetic reasons, I had always started the strut on dropped parts, but now as it has an actual effect, I will make sure to always do this.

IMO though, given the historically wibbly wobbly nature of KSP that we have all come love.... err hate.... err accept, I think Squad should change this to severely reduce the effect struts have on flight. I'm very much pro 1.x, but there are some elements that should be kept. IRL interfaces between objects would be designed into the parts themselves to increase strength, but we don't have that option. Struts are as much of a reflection on how the engine works as much as it is of our craft designs.

[Col_Jessep]

Agreed. Sometimes I have to strut parts on planes due to the "wet noodle" effect and it would be nice if that would not impact the performance that much.

Fun fact: 4 small struts cause a significant difference in performance. They cause more drag than 4 Goo containers (same mass). 0_o

PS: Some screenshots from my testing:

Edited May 24, 2015 by Col_Jessep

[ShadowZone]

that was some great detective work, thanks for sharing your findings!

[WWEdeadman]

OK, that is actually ridiculous... I guess, screw strutting anything from now on.

[Deddly]

The thing is, when you see what a strut looks like, it does intuitatively look like it should have a lot of drag. I think the main problem is that it's presumably the same amount of drag independant of how long the strut is, and the drag only affects the parent part, not the attached part. But in my opinion, it does make sense that they should add drag in some way.

[ShadowZone]

The biggest problem with this situation: you NEED struts if you use the stock fairings, since the fairing bases' nodes are so weak that rockets keep falling apart under minimal amounts of stress.

[eddiew]

Another reason to use KJR... it would be nice if stock aero didn't penalise you so much for not wanting to kersplode

[Chris_2]

The biggest problem with this situation: you NEED struts if you use the stock fairings, since the fairing bases' nodes are so weak that rockets keep falling apart under minimal amounts of stress.

Why is that a problem? So your rocket needs some structural parts that add some drag and weight... Seems only fair... And judging from the pictures in this topic the drag and finally the reduced performance added by the struts seems really negligible..

I think it's more of a problem that the drag of the struts is independent of their size, and how their positioned with respect to the airstream etc. Stuff I see in the exchange forum like connecting wing tips to fuselages with long struts exposed to the airstream should really add a -lot- of drag to the craft.. But I guess that's a simplification we'll have to live with in stock (go to voxel based aero like nuFar).

Edited May 24, 2015 by Chris_2

[regex]

oh. so if you REALLY cared about efficiency, your struts would all start on the disposable parts.

interesting.

I do that anyway to reduce part count.

[Red Iron Crown]

There are some times when it's easier/simpler to start the strut on the upper stage part. An example would be strutting six asparagus boosters, they are installed in pairs so you can only strut two at a time starting from the boosters, start from the core and you can use six way symmetry for quicker, more uniform construction.

[Rhomphaia]

There are some times when it's easier/simpler to start the strut on the upper stage part. An example would be strutting six asparagus boosters, they are installed in pairs so you can only strut two at a time starting from the boosters, start from the core and you can use six way symmetry for quicker, more uniform construction.

You know you can install everything but the fuel lines in 6fold, then split the staging right?

You often do have to strut down if you want to secure a payload in a fairing though, since you can't strut from a fairing base.