K.Yeon

OPT Space Plane Thread

2803 posts in this topic

@captinjoehenry @TheKurgan

Those screenshots don't really provide much useful drag information. Specifically the Aerodynamic Forces Overlay. What you really need to be looking at is the aerodynamic debugging available in the action menus (alt-F12 -> Physics -> Display Aero Data In Action Menus)

With that enabled you can see if a part is shielded or not in the cargo bay (will say 'Shielded: False' if it's not shielded)

I'm looking at the K parts right now and I do see contents being shielded in the cargo bay.

I can also see that K parts that are attached to cockpits and other K parts ARE properly drag occluded, but it's also dependent on how MUCH of the part is occluded. The J-K adapters for instance will naturally have parts of them exposed to the airflow. And angle of attack plays a part there because obviously if you're angled up a bit (even half a fraction of a degree) then the belly is getting airflow. It doesn't take much to get you a nice fat juicy red drag vector (drag is based on velocity squared after all)

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On 2017-5-18 at 5:31 AM, captinjoehenry said:

I have 1 bug and a suggestion.

First of all in the K cockpit I get the hexadecimal color code next to the text on most of the sliders:

Second it would be nice to be able to turn off alarms as the tumble alarm goes off when I am driving my space plane along  the ground and it is really really annoying in the cockpit view.

Third it would be awesome to have a H form cockpit.  As it is I use a 4m nose and an H drone core but it would be great if there was a proper cockpit

The hex on instrument means you just have a out dated ASET props and Rasterpropmonitor, just follow the install guide and reinstall them. And ill change the tumble alarm to something else. But personally it only turns on for a few seconds during take off.
As for new H parts, i can't promise anything yet sorry.

On 2017-5-20 at 3:09 AM, LukeTheYeti said:

Also I may have found an actual bug, I cannot re-enter the J Inline Boarding Ramp. No option to grab or board.so my kerbs are stuck outside :(

The best way to get on it is to have it lowered onto the ground, and have your kerbal walk onto the ramp and the board option should show up.
Keep in mind the airlock collider (area where the boarding option appears) is on the ramp, not near the little door inside... this can't be fixed as i have tried many times the current setup is the only way it works :(

On 2017-5-23 at 11:39 AM, ss8913 said:

@K.Yeon now that FAR is officially released, will there be an updated MM patch to address the OPT-FAR aero compatibility issues (especially the wings) ?

Yeah FAR will be supported for next patch

On 2017-5-25 at 6:23 AM, captinjoehenry said:

Better bug report for no aero shielding with K parts:

With a stock install with only OPT I made a simple K style space plane.  I then used the F12 aero display and there are drag lines for all of the k series parts even behind each other.  So there is no apparent aero shielding going on.  I then put a small monoprop tank inside of the space plane and the monoprop tank even though it was inside of the k series part also generated drag.  In addition the 3 engines on the k series tri coupler also generated drag even though they were behind the whole space plane.  The drag even persisted when the space plane was facing directly prograde in the atmosphere.  I could not find the log in any of the three places it should have been so I am not sure where to get it to include it here.

the whole space plane aero display showing drag on all three of the engines and the control surfaces even though they are behind the tail surface:

The K series fuel tank generating drag even though it is behind the k series cockpit:

ch3G4JL.png

The monoprop tank clipped inside the K series cockpit also producing drag.

ild5oSI.png

This isn't a bug, it's more like the limitation of stock KSP aero physics... If you build a plane out of stock parts, same thing will happen. It seems the stock aero calculation add drag to parts even it's inline with another part. Im not exactly sure how it works but ksp seems to adjust this problem in some way so that the result is somewhat sensible.

Anyway if you embed a part into the k parts that's solid, it will calculate it the same way as the stacked parts. This is why i made the "hollow" versions of the k fuselage, if you put parts inside it, it will be shielded.

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9 minutes ago, K.Yeon said:

This isn't a bug, it's more like the limitation of stock KSP aero physics... If you build a plane out of stock parts, same thing will happen. It seems the stock aero calculation add drag to parts even it's inline with another part. Im not exactly sure how it works but ksp seems to adjust this problem in some way so that the result is somewhat sensible.

Anyway if you embed a part into the k parts that's solid, it will calculate it the same way as the stacked parts. This is why i made the "hollow" versions of the k fuselage, if you put parts inside it, it will be shielded.

Actually, stock drag calculations aren't applying drag to 'inline' parts, except as appropriate for their angle of attack. If the parts are all the same size and the angle of attack is zero then they won't get any drag. 

As I said earlier, those red drag arrows that you can turn on do not tell you what you need to know when looking at a part's drag.:

Let's look at the rocket below: The action menus for both the nose cone on the front and the top most fuel tank on the stack are showing. Notice that the tank's YP and YN faces of its drag cube show 0.00 : 0.00. That means looking along its long axis (its Y axis) it has zero cross section exposed and its drag coefficient is zero. Looking at its drag you will see that is has much less drag than the nose cone. The only reason the tank has ANY drag right now is because of the angle of attack. What that means in terms of the drag cube is that one or both of either the X or Z faces are exposed so we're getting some drag from those. If the angle of attack had been zero then there would be no drag on the tank.

If I'd taken the time to load in an OPT craft with K parts, or any other parts, the results would be much the same.

So, what I'm trying to get across to people here, is that there actually isn't a problem at all. The drag that people seem to think is happening on the 'inline' parts just isn't happening like that. 

FvpJMVW.jpg?1

 

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