[0.90]NEAR: A Simpler Aerodynamics Model v1.3.1 12/16/14

[Chase]

I just want it so that if my rocket is perfectly symmetrical I can let loose with all the thrust I could ever want and not have my rocket suddenly flip out a few hundred feet up.

Basically I just want it to be somewhat more forgiving, though I have no idea how to make that possible.

[Superfluous J]

I just want it so that if my rocket is perfectly symmetrical I can let loose with all the thrust I could ever want and not have my rocket suddenly flip out a few hundred feet up.

Basically I just want it to be somewhat more forgiving, though I have no idea how to make that possible.

I have had no problems launching perfectly symmetrical rockets, or even slightly unsymmetrical ones. How big is your rocket? How are you turning if at all? How much is "all the thrust I could ever want"? Is your rocket going so fast you see fire? White shock waves?

If you want to blow through the atmosphere without regard to aerodynamic effects, you may want to just stick with the stock atmo.

[Nori]

So, I'm having a strange issue. Maybe it is just me, or it is working as intended.

Anyway, I installed Spaceplanes Plus and used his wing pieces to make a attempted spaceplane. I could take off and get to a reasonable speed and anytime I tried to maneuver the plane would flex really bad. Eventually I managed to break it apart. Tried strutting it and I had the same issue.

Is this just a design issue, or maybe I installed something wrong? The plane is pretty simple. Just a fuel tank with rockets as the fuselage and then jet fuel container attached to the sides with jet engines off the back. Simple swept wing design.

I'll post a picture later if anyone is interested.

[biohazard15]

An interesting question.

This design - will it help aerobraking in upper atmosphere, without dipping too low (DRE user here)? These are petal adapters from latest KW.

[Chase]

No, not even white shock cones. It just a few hundred feed up, but at like 200 m/s, the nose started to slide off to one side, and then the entire ship flipped on it's side and became uncontrollable.

[dtrauma]

I'm afraid I have to agree with other posters here. Something in NEAR is giving me a hard time (flatspins, uncontrollable aircraft) in a way that I never experienced before, neither in stock nor in FAR. I realize that that isn't a very helpful report for you, ferram, but I'm wondering - reentry seems to be particularly finicky now, with a spaceplane of mine (spaceplane plus parts, I wonder if they all work correctly with NEAR?) it seems all but impossible not to lose control, even if all I do is keep the nose in the direction of travel, no maneuvers or anything like that. Are there perhaps some mach effects modelled by FAR that actually help with controlling a plane at high speeds? I can't say that I could directly compare planes between NEAR and FAR, though, as switching crafts and saves between mods isn't a good idea right now and so far I refrained from it - still, after your twentieth plane you have some expectations...

I even tried the Aeris 3 and it is very flatspinny in NEAR, too, is this expected? The shape and control surfaces etc. seem reasonable to me, but then, I guess it counts as an imported plane built without the mod so it might be that.

Another thing I noticed is that physics warp seems to give strange results while flying (a plane of mine actually went backwards for a short while), where FAR seemed more forgiving than stock. I realize that this warp all just a big hack from the game so I don't really expect you to look into this, I'd just thought I mention it as it, too, involves planes exposed to large drag forces.

[Tank Buddy]

Seems like a good "buy". Definitely will try it out soon.

[AccidentalDisassembly]

I'm afraid I have to agree with other posters here. Something in NEAR is giving me a hard time (flatspins, uncontrollable aircraft) in a way that I never experienced before, neither in stock nor in FAR. I realize that that isn't a very helpful report for you, ferram, but I'm wondering - reentry seems to be particularly finicky now, with a spaceplane of mine (spaceplane plus parts, I wonder if they all work correctly with NEAR?) it seems all but impossible not to lose control, even if all I do is keep the nose in the direction of travel, no maneuvers or anything like that. Are there perhaps some mach effects modelled by FAR that actually help with controlling a plane at high speeds? I can't say that I could directly compare planes between NEAR and FAR, though, as switching crafts and saves between mods isn't a good idea right now and so far I refrained from it - still, after your twentieth plane you have some expectations...

I even tried the Aeris 3 and it is very flatspinny in NEAR, too, is this expected? The shape and control surfaces etc. seem reasonable to me, but then, I guess it counts as an imported plane built without the mod so it might be that.

Another thing I noticed is that physics warp seems to give strange results while flying (a plane of mine actually went backwards for a short while), where FAR seemed more forgiving than stock. I realize that this warp all just a big hack from the game so I don't really expect you to look into this, I'd just thought I mention it as it, too, involves planes exposed to large drag forces.

I'd have to concur with this, in my own little way - it's completely possible that I'm just horrible at designing airplanes, but when I put something together that both looks like it ought to work and has a decently-well placed CoM and CoL and whatnot according to what I've read here -- trying different parts from different mods, stock, whatever - it's mostly uncontrollable. I can get things off the runway and have them fly straight, but if I try to maneuver, unless I turn veeeeeeeeeeeeerrrrrrrrryyy slowly (as in a few minutes to complete a full turn, just barely tapping controls), just about every plane I've built flips over or goes into a spin. It's as if there's not actually any lift perpendicular to/pushing upward from below the wings anymore if I move the plane off of straight and level, so if I pull up - the angle of the plane changes, but not its actual direction of movement, if that makes any sense - or at least it doesn't change at a rate that that makes any sense for the size of wings or how the plane looks. Result: shortly thereafter, when I pull up a little more, the whole thing flips very quickly.

Is it just horrible design? Does it "feel" right for others? Are most parts/wings not compatible with NEAR? Sorry for lack of pictures, probably makes this rather difficult to answer.

[ferram4]

Well, unless you're using mods with wings that are set up to only apply properties for FAR, but not for NEAR (even though they use the same inputs), then I don't know. If you think you're having issues, pictures and the output_log.txt would probably be helpful. Basically all the information I got from that was "it doesn't work," and that doesn't tell me what's wrong, especially since i can load up NEAR right now and prove that it does.

Other possibilities is simply not enough wing for the plane (which I've seen many, many times in the FAR thread).

Yeah, there are a lot of things that actually make NEAR harder than FAR. Oddly removing lots of the things that people were complaining about makes vehicles less stable, recovering from stalls more difficult (since there are fewer opportunities to design vehicles to remove them), reentries more severe (due to no increased supersonic drag), but if I were to "fix" that, NEAR would simply become FAR, and that's not what people want.

[Wanderfound]

I'm afraid I have to agree with other posters here. Something in NEAR is giving me a hard time (flatspins, uncontrollable aircraft) in a way that I never experienced before, neither in stock nor in FAR.

Possible culprit: I recently installed Active Texture Management and then had to uninstall it as it was making all of my craft behave in very strange ways (oscillating rolls on aircraft, space stations tumbling end over end for no reason unless I kept SAS on, etc.).

I use FAR rather than NEAR, but it may be worth trying without ATM if you have it installed.

[ferram4]

O_o

That makes no sense at all. Besides, I'm running ATM, so it's certainly not the issue.

[Wanderfound]

O_o

That makes no sense at all. Besides, I'm running ATM, so it's certainly not the issue.

I have no idea of how it's happening, but it's a fact that as soon as I installed ATM everything went wonky, and as soon as I uninstalled it everything went back to normal.

The space station one was particularly weird; it's an orbital fuel depot that doesn't even have an engine and the RCS was off. Time warp and it freezes as normal, but as soon as you come out of warp it begins to rotate on the long axis, and the rotation keeps accelerating until you turn the SAS on which gradually damps it out. Turn the SAS off, and it all starts again.

May be a weird interaction happening somewhere; there are a dozen or so mods in play on my game (nothing too wild; FAR, TAC-FB/LS, KAC, Proc Fairings, EVA Parachutes, Enhanced Navball, Spaceplane Plus, Editor Extensions, Mechjeb, EVE with a basic low-res pack; I think that's all).

[riles]

Seem to be having an issue with atmospheric radial decoupler use. What ever stage I am trying to get rid of with radial decouplers just collapse into my ship. I have tried the separating rockets but those simply rip off and cause additional damage. I have no proof that this is due to near but I don't know what else to attribute it to, Is anyone else having these issues? I am thinking of going back to far, I love the idea of more realistic aerodynamics but seem to be having issues with my rockets

[AccidentalDisassembly]

Well, unless you're using mods with wings that are set up to only apply properties for FAR, but not for NEAR (even though they use the same inputs), then I don't know. If you think you're having issues, pictures and the output_log.txt would probably be helpful. Basically all the information I got from that was "it doesn't work," and that doesn't tell me what's wrong, especially since i can load up NEAR right now and prove that it does.

Other possibilities is simply not enough wing for the plane (which I've seen many, many times in the FAR thread).

Yeah, there are a lot of things that actually make NEAR harder than FAR. Oddly removing lots of the things that people were complaining about makes vehicles less stable, recovering from stalls more difficult (since there are fewer opportunities to design vehicles to remove them), reentries more severe (due to no increased supersonic drag), but if I were to "fix" that, NEAR would simply become FAR, and that's not what people want.

I mean - I'm guessing that what's going on is a design issue, but I sure can't figure it out. Either that or it's a combo of my bad design + parts that don't interact well with NEAR/FAR = really weird behavior. Or it's that I have 98395839583 mods and something, somewhere, is causing things not to work right, or KSP x64 is. Figured I'd throw it out there since it sounded like dtrauma was experiencing vaguely what I was.

[Eleven]

Seem to be having an issue with atmospheric radial decoupler use. What ever stage I am trying to get rid of with radial decouplers just collapse into my ship. I have tried the separating rockets but those simply rip off and cause additional damage. I have no proof that this is due to near but I don't know what else to attribute it to, Is anyone else having these issues? I am thinking of going back to far, I love the idea of more realistic aerodynamics but seem to be having issues with my rockets

This is a known bug and has nothing to do with NEAR or FAR.

See here: http://forum.kerbalspaceprogram.com/threads/88026-Radial-Decouplers-3-75m-Decoupler-Issues-%28Return-of-the-Kraken-0-24-2%29

[riles]

Awesome! Guess Im just a moron then.

[MalfunctionM1Ke]

Ferram, is the Atmospheric Model in NEAR the same as in FAR or is it something in between the Stock Model and the FAR Model?

I am concerned about the soupy-ness and how fast you can go at low altitutes.

A terminal velocity indicator would be nice becuse Kerbal Engineer is not showing any.

[JeffreyCor]

I'm in agreeance on an indicator. While the displays for FAR is very complex, some basic information display for NEAR would be fantastic

[NathanKell]

Terminal velocity in NEAR is going to be insanely high, since one of the simplifications was the removal of supersonic (extra) drag.

[Superfluous J]

Terminal velocity in NEAR is going to be insanely high, since one of the simplifications was the removal of supersonic (extra) drag.

Insanely as in, "So long as your ship's not on fire, you're fine" or somewhere less than that?

[ferram4]

Depends on the ship. 400 - 1500 m/s at SL for rockets ranging from moderately sized to monstrosities. Chasing terminal velocity is not a thing that you can manage to do.

[Renegrade]

Depends on the ship. 400 - 1500 m/s at SL for rockets ranging from moderately sized to monstrosities. Chasing terminal velocity is not a thing that you can manage to do.

Is it even desirable to do so in any case?

The optimal ascent speed is where the sum of gravity losses and aero losses are the lowest .. will that even be at terminal velocity?

I've always thought that the terminal velocity thing was an artifact of Stock's bizarre aero mechanics, and that with real aero, the actual optimal speed would be a separate number from terminal velocity and that any matching therein would be a coincidence and vehicle-specific.. is that correct?

[NathanKell]

Saturn V gravity losses: ~1800m/s.

Saturn V drag losses: ~100m/s.

Imagine just what kind of TWR you would need (and what kind of unobtainium-shielded rocket) to manage to equalize those two and survive.

[dtrauma]

Well, unless you're using mods with wings that are set up to only apply properties for FAR, but not for NEAR (even though they use the same inputs), then I don't know. If you think you're having issues, pictures and the output_log.txt would probably be helpful. Basically all the information I got from that was "it doesn't work," and that doesn't tell me what's wrong, especially since i can load up NEAR right now and prove that it does.

OK, I'll do that with some of the affected planes. Is there a way to check if wings are configured correctly? I mostly used spaceplane plus. I'd post some crafts, too, if exchanging them wasn't so problematic right now.

I guess one thing that worsens the issue is the lack of any meaningful statistics - all the display mods I tried (VOID, NanoGauges) that display info for FAR don't seem to work with NEAR yet - basically, with NEAR's simplified model, wouldn't it be easy to display one drag coefficient for going up (VAB) or forward (SPH)? And perhaps a center of drag marker... If I don't forget something obvious, that's all that's needed to predict vehicle behaviour (you could check angles of attack by turning the whole vehicle in the editor).

ninja edit: Question - has the center of lift shown in the editor any relevance with NEAR?

[dzikakulka]

I would also enjoy some info window or right-click-debug toggle - if it's not already implemented and I'm just dumb.

Sometimes I build... weird... things and it would be great to see if drag is distributed properly.

Thanks for the graet mod!