What are the benefits of size adapters?

[steuben]

Leaving aside esthetics, because hey the pretty.

Doing some quick searches I'm coming back with some early stuff, some 1.0.x stuff but  nothing too recent.

Are there any benefits using the size adapters structurally? Decreased wobble?

Are there any benefits using the size adapters aerodynamically? Less drag?

 

[ForScience6686]

Reduced drag, you don't want flat edges facing prograde.  

[FullMetalMachinist]

Just now, ForScience6686 said:

Reduced drag, you don't want flat edges facing prograde.  

Yep. The game sees that you have a size 1 part stuck directly to a size 2 part, and it will take into account that there are flat edges in the airflow and adjust drag accordingly. 

I'm not sure about structural strength increase, though. 

[A_name]

As others mentioned they reduce drag. Structurally, if you look closely you will see that different parts have different sizes of attachment node, i.e. the green sphere that appears when you pick up the part. Bigger green spheres mean a stronger attachment node. Bigger parts tend to have bigger/stronger nodes. Adaptors tend to have stronger nodes that fit the bigger side. This may or may not be useful for you, but I thought it's good to know.

[bewing]

Anything structural can be done just as easily with struts/autostruts.

So yeah, it's a drag thing. But the effect isn't huge, you understand.

Using a rockomax adapter between a 2.5m and 1.25m section will get you to orbit with maybe 10% more dV left. You can easily see it just by trying it both ways and comparing fuel levels. For all the rest of your trip in space, the adapter hurts a tiny bit because of the small extra mass, of course -- but they are not heavy like fairings, so the added mass is pretty small.

 

[Kryxal]

Of more benefit are the combined fuel tank and adapter, I think.

[Aegolius13]

9 minutes ago, Kryxal said:

Of more benefit are the combined fuel tank and adapter, I think.

Agree.  I did some drag testing earlier in 1.2.  Adapters,  adapter tanks and interstage fairings all provide about the same drag benefits.   So when possible,  might as well use the one that gets you fuel too.

[foamyesque]

They also just look good.