wind tunnel

[crenelatedcheese]

So now in the VAB you can see how different parts affect the drag of something, but don't many things affect fluid flow around a spacecraft? Like calculating drag coefficient requires reference area. I think having to deal with a bunch of numbers while editing the spacecraft itself wouldn't be a good experience, so there should be an option to set up an environment through a graphical UI to teach the user fluid dynamics in a more abstract way than trial and error.

[TLTay]

This would be a pretty neat idea. I enjoyed learning FAR aerodynamics, but a visual expression would make it easier to learn.  I'm not sure which direction they are going to go with aerodynamics in KSP2. True-to-life aero can be counterintuitive and frustrating. I know a large part of the audience (especially younger players) love to build simple aircraft and whatnot, and using the half-baked stock aero system in KSP1 is much easier than having to worry about anti-shock bodies, transsonic stability issues, and area rule shaping, to name a few. I'm not sure if they will go KSP1 style where fluid flow simulation would only reveal the issues with the aero model, or more realistic and less accessible...  Maybe they will do both as a toggle/difficulty option?

[SOXBLOX]

I would LOVE a stock aerodynamics where profile matters. Pleeaasseee?????

[Single stage to ocean]

FAR style aero as a difficulty setting, and when activated, it provides a tutorial and a wind tunnel for a sample craft, and tells you tips

[Guest]

Another vote for FAR style aero with the design tools to make it work. It should not be optional, it should just be the way aero works.

There’s a common assumption here that FAR is mega hard and hardcore, but it isn’t really. It’s just different and more realistic. You can get that impression though if you jump into it and suddenly find that your planes don’t fly anymore, and then get frustrated when you have to un-learn the tricks you used to make stock aero work and learn a few things about how real aerodynamics work.

If you had FAR from the start with the design tools to make it work for you, I don’t think you’d give it a second thought. Rockets shaped and balanced like rockets would work, as would planes shaped and balanced like planes. And I think it would be a lot more rewarding to learn actual aerodynamics as opposed to learning to optimize drag occlusion boxes.

[Single stage to ocean]

It can get difficult expalining shock cones and etc to new players, who might be wondering why their control surfaces aren't working above a certain speed. Make it a difficulty setting.

[Guest]

5 hours ago, Single stage to ocean said:

It can get difficult expalining shock cones and etc to new players, who might be wondering why their control surfaces aren't working above a certain speed. Make it a difficulty setting.

It's just as difficult to explain why some part is producing massive drag although you can clearly see that the shape is aerodynamic. "You need to node attach it, surface attaching it won't do it" isn't intuitive at all.

(OTOH I have no categorical objection to making some features of the aero model optional, if they turn out to be too difficult in playtesting. Shock cones, for example. But building in two separate aerodynamics models as difficulty options strikes me as a bad idea for a number of reasons -- it'll make craft sharing much more difficult, it'll require separate tutorials, and it'll be a major duplication of effort.)

Edited May 20, 2021 by Guest

[pandaman]

I agree with @Brikoleur here.  Stock needs only a single aero system, whatever it may be.   Why program two different systems?    Any difficulty settings should simply modify or toggle aspects within it.

I haven't used, and dont intend to use, FAR in KSP1.  But I do think opting for a system like it in KSP2 is the right aporoach.  KSP already teaches the basics of real  rocket science, why not do the same for aerodynamics?  After all aerodynamics do play a significant role in spacecraft design and operation.

Edited May 20, 2021 by pandaman

[Single stage to ocean]

It is also difficult to ksp 1 players.

[swjr-swis]

1 hour ago, Brikoleur said:

building in two separate aerodynamics models as difficulty options strikes me as a bad idea for a number of reasons -- it'll make craft sharing much more difficult, it'll require separate tutorials, and it'll be a major duplication of effort.

I was initially going to simply agree, but then I considered that KSP, in its debug menu, already incorporates multiple ways of changing how physics work in the game. And we already deal with sharing craft that use/expect different aerodynamics.

I would prefer KSP2 to move towards more realistic aerodynamics as a default, personally, and I would probably end up using that exclusively, but it doesn't seem to be entirely objectionable or out of the question to maintain an optional 'old school' switch.

 

[mcwaffles2003]

15 minutes ago, swjr-swis said:

but then I considered that KSP, in its debug menu, already incorporates multiple ways of changing how physics work in the game. And we already deal with sharing craft that use/expect different aerodynamics.

The debug menu lets you toggle aspects of the model, it doesn't have 2 separate models to reference though as would be the case with choosing stock or FAR

[pandaman]

1 hour ago, Single stage to ocean said:

It is also difficult to ksp 1 players.

I think this is mainly because FAR is just 'different', and therefore needs us to alter the way we currently do things.  If it were the stock method from the start we would all have just grown up with it and it would be normal, and therefore no harder than the current stock implementation.

When they changed things a while ago so that realisic gravity turns became a 'thing' we all had to adjust from the very unrealistic 'straight up to 10km then crank over' method to reach orbit, and the same would be true here.

 I'm not suggesting switching KSP1 to FAR, but we would all adapt ok if they did.  Having a similar system to FAR as the 'standard' for KSP2 would not be a bad thing IMO, and probably better than using something like the KSP1 stock method.  In fact I think it would be an error of judgement to not do so.

Edited May 20, 2021 by pandaman

[Guest]

59 minutes ago, swjr-swis said:

I was initially going to simply agree, but then I considered that KSP, in its debug menu, already incorporates multiple ways of changing how physics work in the game. And we already deal with sharing craft that use/expect different aerodynamics.

I would prefer KSP2 to move towards more realistic aerodynamics as a default, personally, and I would probably end up using that exclusively, but it doesn't seem to be entirely objectionable or out of the question to maintain an optional 'old school' switch.

As I said above, I wouldn't object to difficulty settings modifying the physics or the aerodynamics model, for example you could have an "easy" setting that disables all the supersonic effects. However, implementing two separate optional aerodynamics models just sounds like a giant PITA in so many ways it's not worth it .

[swjr-swis]

I think we've gone off on a tangent discussing the physics implementation, when the OP is specifically requesting a type of UI/tool to assess the airworthiness of the WIP plane in a theoretical manner (ie. like it's done in the real world) instead of having to fly to see what it does.

To that I say: yes, please. I would very much like a tool of such ilk while building/designing our craft, regardless of how exactly aerodynamics are implemented in the game.

[Jack Mcslay]

I would find it pretty useful, much less frustration from trial and error trying to get a plane to generate enough lift

[Single stage to ocean]

Maybe a max speed calculator for certain AOAs, eg at 1 aoa max speed of 1km/s. 

[Dientus]

Would help me a lot for sure.

 

Could even help for fast moving vehicles/boats to figure where lift would occur and where to push down effectively to keep it grounded (watered? LoL)

 

[Guest]

Just a thought -- a FAR style aerodynamics model might actually make game development easier. As things currently stand, each part needs to be tested and tuned to work with the aerodynamics model; I remember devs tearing their hair out when, say, the spherical Making History command modules went through the atmosphere "like a greased cat," or issues with the Mk2 parts producing too much drag, and so on. If aerodynamics was based on the actual shape of the craft, they could just ignore that -- in addition to the shape, all they'd need to know is the centre of mass, and that's easy to calculate.

Of course the model itself would be more work, but it would pay off in the long run by making it that much easier to create new parts.

[shdwlrd]

The direct answer to the question. Something to show you the aero forces and stability in the VAB for the different parts of the flight regime would be very handy. 

For the extra discussion. I wouldn't be opposed to a FAR like aero model.

[OHara]

Even KSP1 has an automated analysis of lift and drag, for each separate part.  If a modder makes a part, KSP1 figures drag coefficients and surface areas and caches them in PartDatabase.cfg.   Motivated modders can override KSP1's analysis in the cfg file.

3 hours ago, Brikoleur said:

a FAR style aerodynamics model might actually make game development easier

Well, KSP1's method of getting some aerodynamics information from analysis of the shape of the model, has caused some problems.

+ The KV-* pods are dense and have smooth models, so they re-entered the atmosphere fast.  The part-designer replaced the shape-based aerodynamics with numbers corresponding to a flat-sided cuboid, and now these pods are draggy enough to get a bug report. (I like the automatic analysis so I delete the override.)

+ The MK2 fuselage parts do use the automatically-figured lift and drag based on their shapes (which look reasonable to me) but then the KSP1 drag model applies the bottom-face drag very quickly (I think too strongly) as we pitch up. 

FAR chooses not to analyse the shape of wings completely on its own, but requires modders to provide a configuration to describe the intended function of the wing.  

Given the success of FAR and the history of KSP1, I think a FAR-like approach would be reasonable for KSP2.   Implementation does seem to require a good deal of care, though.

The parameters going into the model could still be adjusted to make a broadly-accessible game.  For example control surface could be allowed to work reasonably at trans-sonic speeds, until players want to mod-in the realism.

[crenelatedcheese]

oops, I turned off notifications for this thread, sorry

I just think making a wind tunnel will be easier to progress in the game while actually learning something

like the time I sent a spacecraft that just broke apart in eve's atmosphere

In the wind tunnel we can test different profiles,  air density, spin the aircraft around, turbulent flow vs laminar flow, etc

makes it easy to land in one piece 

[Guest]

42 minutes ago, crenelatedcheese said:

In the wind tunnel we can test different profiles,  air density, spin the aircraft around, turbulent flow vs laminar flow, etc

Heh, those things need to be simulated first. KSP's aero model is nothing like that. A wind tunnel would just demonstrate exactly how primitive it is. 

[crenelatedcheese]

you have a point lol, ksp1 simulates with nodes right

[Lt_Duckweed]

Ksp 1 actually simulates based off of what are called "drag cubes".

Each part is simulated to have 6 faces, each face has an area, and a streamlining factor.  Each attachment node on a part is tied to a specific face.  If you attach two parts via nodes, the area of the drag cube faces associated with those 2 nodes gets mutually subtracted from each other.

After the exposed area is calculated, each of the 6 faces has 3 types of drag applied based on a variety of factors.

The three types are:

1. Frontal drag (a component of form drag)

2. Side drag (analogous to real world skin drag)

3. Backface drag (the other component of form drag)

These get calculated based on the angle of each of the 6 faces to the airflow.

 

A full writeup exists here: https://github.com/Ren0k/Project-Atmospheric-Drag

Edited May 20, 2021 by Lt_Duckweed

[Incarnation of Chaos]

On 5/20/2021 at 1:46 PM, OHara said:

Even KSP1 has an automated analysis of lift and drag, for each separate part.  If a modder makes a part, KSP1 figures drag coefficients and surface areas and caches them in PartDatabase.cfg.   Motivated modders can override KSP1's analysis in the cfg file.

Well, KSP1's method of getting some aerodynamics information from analysis of the shape of the model, has caused some problems.

+ The KV-* pods are dense and have smooth models, so they re-entered the atmosphere fast.  The part-designer replaced the shape-based aerodynamics with numbers corresponding to a flat-sided cuboid, and now these pods are draggy enough to get a bug report. (I like the automatic analysis so I delete the override.)

+ The MK2 fuselage parts do use the automatically-figured lift and drag based on their shapes (which look reasonable to me) but then the KSP1 drag model applies the bottom-face drag very quickly (I think too strongly) as we pitch up. 

FAR chooses not to analyse the shape of wings completely on its own, but requires modders to provide a configuration to describe the intended function of the wing.  

Given the success of FAR and the history of KSP1, I think a FAR-like approach would be reasonable for KSP2.   Implementation does seem to require a good deal of care, though.

The parameters going into the model could still be adjusted to make a broadly-accessible game.  For example control surface could be allowed to work reasonably at trans-sonic speeds, until players want to mod-in the realism.

Well that's the beautiful thing about math and computers, nobody said that you have to plug realistic values into your equations.

You want KSP style lift? That's a single change to buff all wings, and then you get to see the corresponding increase in drag. 

I actually think letting people play with the aero models parameters and seeing how it would affect everything else has a massive educational potential. Kinda like universe sandbox for little green space monsters and their cute planes. 

You can also have the settings as sliders (with the scale from "realistic" to "full kerbal" ) for the people who don't think reading about the XB-70 riding it's own shock cone at 3AM is a good time. 

And then an actual panel for raw input for nerds or debugging.

But I'm not going to bet money for seeing any of those, since the dev team mentioned KSP style aero a long time ago.