Adapters in KSP 1.0

[Layl]

Previously in KSP I always skipped adding adapters, since they had no use with the drag physics at the time. In KSP 1.0 the drag physics were updated, is it now worth it to add for example the FL-A10 adapter between 0.625m parts and 1.25m parts where it previously just added more weight and drag?

Edited May 16, 2015 by Layl

[Snark]

Yes, they actually have a point now.

It's a pretty simple experiment to do... just launch a little rocket with/without the adapter and see which goes higher.

[Geschosskopf]

Adaptors have always had a point even with the old aero. If you don't use an adaptor, your rocket's diameter changes abruptly. In KSP, just as in real life, this creates a stress concentration. In KSP, this results in a wobbly rocket that flexes at the diameter change, and can, in some cases, lead to the rocket breaking there. Putting an adaptor in to make a smoother transition of diameters mostly solves this problem.

[adinfinitum]

The way I think it works, is that for parts of different sizes connected by nodes, the lower part contributes drag proportional to the uncovered area. So if you start with a 1.25m part, a 2.5m fuel tank directly underneath will have more drag than if an adapter was there, because the adapter has less drag than a fuel tank.

[Snark]

Adaptors have always had a point even with the old aero. If you don't use an adaptor, your rocket's diameter changes abruptly. In KSP, just as in real life, this creates a stress concentration. In KSP, this results in a wobbly rocket that flexes at the diameter change, and can, in some cases, lead to the rocket breaking there. Putting an adaptor in to make a smoother transition of diameters mostly solves this problem.

Really? I never noticed a problem with it. KSP doesn't appear to me to model "bendiness" all that well-- the reason why sudden diameter changes make a difference in real life is that real-life objects can bend all along their length. KSP appears (as far as I can tell) to have rigid parts (they squash under stress, but don't bend), and the bending happens only at the joints, which I think is just a function of what the node size is. The more joints you have, the more opportunities to bend. I would say that adding an adapter makes bending worse because now there are two joints instead of one (though not a lot worse, since one of the joints is a larger-size node and is stiffer).

In any case, in pre-1.0 I never bothered with adapters and never had any structural problems from it. (And even if there were, could just use struts, which were massless, which not all adapters were.) The only time I ever used adapters was either cosmetic, or if I needed to physically space things out to make room for radially attached parts and what-not.

In any case... there's a lot more reason for them now. Flat surfaces perpendicular to the airflow = major bad.