Does drag effect every "non-wing" part on a craft, regardless of nose cones/node stacked parts? pics

[HafCoJoe]

I've been building and testing a new shuttle, and I've been noticing that the Mk3 cargo bay as well as every other hull piece is experiencing drag effects, even though they are attached in a line behind a nosecone. Is this unusual?

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- Avera9eJoe

[Reddeyfish]

edit: nvm

[HafCoJoe]

Doing one more quick experiment, yes it appears as though KSP takes every part on the craft (that isn't physics-less) into account, regardless of if they are attached in a line or have nosecones or not. Does this mean it is still better to reduce part count to go fast then to try to go pointy? I thought that was the opposite of what was planned for the new aero...

[maccollo]

No, it doesn't. Try to create and fly these two rockets. The first one cannot break the transonic wall until it gets really high up, despite the huge amount of thrust. The second rocket smashes through it like it's barely there.

[Eric S]

There's a bug in the mk3 cargo bay that causes this, from what I've heard. It causes anything stacked behind it to not be occluded.

[Claw]

There's a bug in the mk3 cargo bay that causes this, from what I've heard. It causes anything stacked behind it to not be occluded.

Yes, this. And I'm working on it. Possibly will be added to my fixes tonight.

Cheers,

~Claw

[Claw]

Just to avoid confusion, fuselage pieces will generate drag due to their skin friction. However, it looks like there's also a bug with the Mk3 cargo bays, where they aren't occluding properly.

[Claw]

Mk3 cargo bay occlusion has been fixed (I hope) in my most recent release. It should (hopefully) help out a bit.

Cheers,

~Claw

[panzer1b]

No, it doesn't. Try to create and fly these two rockets. The first one cannot break the transonic wall until it gets really high up, despite the huge amount of thrust. The second rocket smashes through it like it's barely there.

https://dl.dropboxusercontent.com/u/22015656/setup1.png

https://dl.dropboxusercontent.com/u/22015656/setup2.png

This is because radially attached parts do not have occlusion enabled on them period (even if you clipped those tansk inside the hull youd still have insane drag.

Anyways, from my experience:

1st part in a stack is always fully exposed, and the last part in a stack is something like 50-66% drag of a fully exposed part. STuff in the middle gets occlusion, but that occlusion does not quite disable drag, but instead lowers it to like 10% or something, and the amount of drag also increases as you deviate from prograde vector.

Basically from my own experience, the more crap you stick in a stack the better, as the front/rear parts are going to have alot of drag applied to them, and the stuff in the middle is going to have anywhere from major to some drag decreases. While 1.0.2 fixed most of the exploits, its still not a true vector based occlusion system. Things that are radially attached regardless of where they are placed on the craft will ALWAYS get full drag applied, period. This makes part clipping pointless from a drag saving perspective (the new exploity crafts involve shoving lucridious amounts of stuff into cargo bays, as those 100% disable drag on anything internal to them.

The drag works fine if you make conventional aircraft, but most truly high performance craft will abuse cargo bays for their unique ability to disable drag on anything inside (fuel droptanks go very nicely inside on of these, as do things like batteries, RTGs, solars, heck even ion engine clusters work from inside a cargo bay). The trick is to minimize part count outside of any bay, and place all radial stuff that isnt essential to aircraft appearance or function inside said bays.

[Claw]

Anyways, from my experience:

1st part in a stack is always fully exposed, and the last part in a stack is something like 50-66% drag of a fully exposed part. STuff in the middle gets occlusion, but that occlusion does not quite disable drag, but instead lowers it to like 10% or something, and the amount of drag also increases as you deviate from prograde vector.

This is pretty much spot on for subsonic drag.

Although I am curious why you consider putting things inside a cargo bay as exploity and abusive from a drag perspective? Considering that parts placed inside have basically become internal to the fuselage and are out of the wind stream.

Cheers,

-Claw

[panzer1b]

This is pretty much spot on for subsonic drag.

Although I am curious why you consider putting things inside a cargo bay as exploity and abusive from a drag perspective? Considering that parts placed inside have basically become internal to the fuselage and are out of the wind stream.

Cheers,

-Claw

Well the placing of parts inside these isnt the exploit, its when you take a 1.25m service bay, and shove 15 ion engines+27 ion fuel tanks+100 batteries+3 RTGs+1 probe core+ 2 monoprop thrusters+some other stuff ALL INSIDE IT AT ONCE!

Noone in their right mind can call a craft that has that onboard 100% legit, even if it can make a laythe roundtrip because of it!

this is an example craft:

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that thing has teh entire ion system shoved into the 1.25m bay.

Edited May 4, 2015 by panzer1b

[Superfluous J]

That's not abusing the cargo bay. It's abusing part clipping.

You can do that without a cargo bay. Just clip everything into your vessel.