[1.3.1] Ferram Aerospace Research: v0.15.9.1 "Liepmann" 4/2/18

[blowfish]

41 minutes ago, LordOfMinecraft99 said:

Hi, i have a problem whenever i am playing with R.O/F.A.R. In the SPH it says the wings (all the wings, both stock and modded) dont have and lift values and they act as though the wings are just structural parts, Second, out on the runway, the wings don't provide any lift.

Could you find and upload KSP's log?  Instructions on how to find that are in the first link in my signature.  The log is almost always necessary to debug issues like this,

[Motokid600]

On 7/30/2016 at 6:37 AM, RageMode said:

 

Try and post a picture if you can of the craft. You say your staging at 5km? That's incredibly way too low. That profile sounds like you have something akin to a sounding rocket in which case you need significant fins. Oh and in the meantime... Try a pointier fairing. Not kidding. Had a similar issue awhile back and I found out I was making my fairings too blunt.  Additionally... The way you make it sound the rocket uses a solid first stage, then seperates at 5km. Small rockets are very susceptible to aero forces. Especially if the rocket loses a portion of its length after staging. So what I do to add a lot of stability is take structural tanks with no fuel ( make sure the tanks with fuel are at the top ) and extend the length of a stage. Helps a lot.

Edited July 31, 2016 by Motokid600

[Ourworldalpha1]

Hello nice mod you got here,

But i am using the latest 1.1.3 Ferram Aerospace install and i am still getting that pesky tweakscale Bug

I am doing an Kerbal 6.4X Re-scale sandbox@Carrier and i am trying to make rocket replica but i cant launch anything with this DAMN Bug, because My rockets are made literally of All Procedural@Tweakscaled Parts,Tanks,RCS,Batteries Ect

not looking for an answer right away, just letting you know that this Bug is Not Fixed with the Newest Version of your mod

Like an Reply 

Thanks

P.S the link will be a broken image just right click on it an open it that way Sorry

i got no Logs or Replication steps but Here are some pics of the Bug at work

Edited July 31, 2016 by Ourworldalpha1

[LordOfMinecraft99]

Here is my log:

https://drive.google.com/open?id=0B-Rnwo9xqjx0VWxIYUwwRGVfLUE

[blowfish]

2 hours ago, LordOfMinecraft99 said:

Here is my log:

https://drive.google.com/open?id=0B-Rnwo9xqjx0VWxIYUwwRGVfLUE

That log shows KSP crashing before it even finishes loading.  Did you kill it or is that an actual crash?  If you killed it, could you wait for it to reach the main menu at least and then get the log?  Also, before you open KSP, please delete GameData/ModuleManager.ConfigCache so that ModuleManager will re-patch everything and it will show up in the log.

Edited July 31, 2016 by blowfish

[LordOfMinecraft99]

oops, wrong log....

oops, wrong log....

Here is the correct one.

https://drive.google.com/file/d/0B-Rnwo9xqjx0M21ZZEhiWF96ZTA/view?usp=sharing

[Bloojay]

500 Pages, nice.

Also thanks for fixing body lift on angled fuel tanks

[blowfish]

5 hours ago, LordOfMinecraft99 said:

oops, wrong log....

Here is the correct one.

https://drive.google.com/file/d/0B-Rnwo9xqjx0M21ZZEhiWF96ZTA/view?usp=sharing

I don't see anything obvious that would be causing this behavior but I do see a few things wrong

• You're a version behind on Modular Flight Integrator
• Tac Life Support is spamming exceptions
• Firespitter is also out of date and causing exceptions
• A couple many of the SXT parts are causing issues both for stock drag cubes and FAR

[LordOfMinecraft99]

How do i fix this?

[blowfish]

2 hours ago, LordOfMinecraft99 said:

How do i fix this?

Update Modular Flight Integrator

Update Tac Life Support ... looks like you're a version behind

Update Firespitter (do I really have to say this?)

Don't use the SXT props for now

See if that fixes anything.  If not, post your log again and there will be a lot less noise to sort through.

Edited August 1, 2016 by blowfish

[LordOfMinecraft99]

I updated ALL the mods, and it still does not work!

 

[baldamundo]

Where's the documentation for the flight assistance toggles? I've forgotten what they do and my google-fu is failing me

[blowfish]

4 hours ago, LordOfMinecraft99 said:

I updated ALL the mods, and it still does not work!

 

Try posting your logs again, along with ModuleManager.ConfigCache.  I will see if I can identify anything new.  It's definitely easier without noise from outdated mods.

[LordOfMinecraft99]

Heres the new log

https://drive.google.com/file/d/0B-Rnwo9xqjx0c28wbDRCd3pjVEU/view?usp=sharing

[blowfish]

3 hours ago, LordOfMinecraft99 said:

Heres the new log

https://drive.google.com/file/d/0B-Rnwo9xqjx0c28wbDRCd3pjVEU/view?usp=sharing

Okay, well I see that something is causing FAR to spam exceptions.  The next step would be figuring out what mod is causing FAR to do that (Tweakscale might be a good first try).  This doesn't seem to happen for anyone else, so it has to be one of the mods you have installed (or a bad install).  Here's what I would recommend, if you want to get to the bottom of this as quickly as possible: Start with a clean install with only FAR.  Slowly add mods back in until you see the problem again, in which case you know which mod caused it, or you don't, in which case it was an install error.

Spoiler

ArgumentOutOfRangeException: Argument is out of range.

Parameter name: index
  at System.Collections.Generic.List`1[FerramAerospaceResearch.FARPartStressTemplate].get_Item (Int32 index) [0x00000] in <filename unknown>:0 

  at FerramAerospaceResearch.FARAeroStress.DetermineStressTemplate (.Part p) [0x00000] in <filename unknown>:0 

  at FerramAerospaceResearch.FARAeroComponents.FARAeroPartModule.Start () [0x00000] in <filename unknown>:0 
 
(Filename:  Line: -1)

NullReferenceException: Object reference not set to an instance of an object
  at ferram4.FARControllableSurface.CalculateSurfaceFunctions () [0x00000] in <filename unknown>:0 

  at ferram4.FARControllableSurface.FixedUpdate () [0x00000] in <filename unknown>:0 

 

By the way, unrelated to your problem but you only need one copy of ModuleManager (the latest version).  Others will disable themselves if they see another one.

[Bloojay]

... Ok how the profanity do I disable the whole "planey go boom boom if you turn to hard" feature, I built my shuttle like a tooting brick its not going to shatter at a little Mach 3 sideslip.

[ferram4]

@RageMode: If it's only happening during staging, then the problem is that your upper stage isn't stable while you're still within the atmosphere.  The realistic solution to this is... either wait until you're further out of the atmosphere to stage (like standard orbital launch vehicles) or put fins on the upper stage to stabilize it (like on sounding rockets).  Also, make sure that your fairing isn't too much wider than the rest of the rocket, or else that'll produce silly amounts of body lift and make things a lot worse.

@LordOfMinecraft99: The first thing I would do is clear out the extra ModuleManager files you have in there.  You have multiple copies of the same MM in your save and while I know that MM will disable older copies, I don't know how it reacts to multiple MMs that are the same version.

The second thing I would do is provide repro steps for the issue that use as few mods as possible.

The third thing I would do is reinstall all of FAR (deleting the FAR folder completely) because the second FAR exception indicates that one of the configs isn't being loaded or something similar.  That exception will never happen otherwise.

@Ourworldalpha1: There are no FAR bugs with Procedural Parts, so I don't know what you're talking about there.

The only FAR-specific Tweakscale bug was wrt the mass of tweakscaled wings.  That was fixed, and there are no other Tweakscale-FAR interactions that occur unless something has changed in Tweakscale that prevents it from telling FAR to re-voxelize things.

In any case, you need to provide more information before anyone can do anything, because all of the known Tweakscale bugs have been fixed long ago.

@baldamundo: The wing leveler levels wings.  The pitch damper damps pitch.  The yaw damper damps yaw.  The AoA limiter limits AoA.  The Dynamic Control adjustment reduces control inputs to counter increasing dynamic pressure.  At least the last of those doesn't sound quite so obvious.

@Bloojay: Well, there is an option in the space center scene's FAR menu, that's generally a good place to start.  On the other hand, body lift at high dynamic pressures will tear pretty much everything apart, including space shuttles.  Citation: Challenger post-ET disintegration.

[RageMode]

12 minutes ago, ferram4 said:

 

@RageMode: If it's only happening during staging, then the problem is that your upper stage isn't stable while you're still within the atmosphere.  The realistic solution to this is... either wait until you're further out of the atmosphere to stage (like standard orbital launch vehicles) or put fins on the upper stage to stabilize it (like on sounding rockets).  Also, make sure that your fairing isn't too much wider than the rest of the rocket, or else that'll produce silly amounts of body lift and make things a lot worse.

 

Makes sense. Though I'm not really playing with the stock solar system any more. I liked RSS much better but couldn't deal with the stuttering it caused. But since I've found MemGraph and its ability to increase the GC padding, which reduces the stuttering drastically, I'm back on it. Interestingly, I find it much easier to design rockets that fly stable in RO with FAR than stock with FAR. Probably because the engines are balanced better for realistic rocket design in RO.

Edited August 2, 2016 by RageMode

[baldamundo]

4 hours ago, ferram4 said:

@baldamundo: The wing leveler levels wings.  The pitch damper damps pitch.  The yaw damper damps yaw.  The AoA limiter limits AoA.  The Dynamic Control adjustment reduces control inputs to counter increasing dynamic pressure.  At least the last of those doesn't sound quite so obvious.

By 'damping' do we mean like reducing the mad see-saw effect that results from trying to fly a plane with decent control authority using a excrements keyboard interface instead of a joystick (how I miss the on-screen joy stick mod...)?

And how exactly does the AoA limit AoA? And do they work (and if so, are they useful) running at the same time as e.g. MechJeb's SmartASS or similar?

[Ourworldalpha1]

thanks for answering me Ferram

The phanton levitation Bug was caused by AIES Batteries on my spacecraft not your Mod

Anyway awesome mod you got here,Keep up the Good Work

[Vladokapuh]

I absolutely love this mod, i love how the planes fly with it, most of my stuff works even better with FAR than without it, but i have one issue.
I cannot land anything, landing gear just bounces hard no matter how gently i land, with far disabled i can make landings 3x harder without any bouncing whatsoever.
I tried messing with spring strength and dampers, but no success, i tried lowering my landing speeds to as low as 50m/s with almost no vertical speed, still nothing, heavy bounce and crash.

Any advices? Is this expected behavior or something going wrong?

Edited August 3, 2016 by Vladokapuh

[Boris-Barboris]

@ferram4 I'd like to point out one particular thing, that really bothers me. It was mentioned earlier by @Kitspace and correlates with what I observe. Wings stall and post-stall behaviour.

Prancing, inability to make a flip in pitch. Critical AoA is an inpenetrable brick wall, wich throws you back to low AoA region with strong, ugly and "unnatural" tuck. For example, this configuration, while being strongly unstable, cannot exceed critical AoA:

This... doesn't look even remotely realistic, honestly, even though I learned well, how untrustworthy intuition is.

This CoP shift is just too big, not to mention it should actually be inversed for swept wings. This makes building anything supermaneuverable very hard.

I looked into the source, https://github.com/ferram4/Ferram-Aerospace-Research/blob/master/FerramAerospaceResearch/LEGACYferram4/FARWingAerodynamicModel.cs#L1082
is responsible for CoP shift. First thing I noticed, for a typical CoP location of mac/4 that 0.75 is very big, I'm concerned that in cooperation with mach effects (or even without them) it will move CoP right to the trailing edge (or further) in some cases, wich should not really be the case, imho.

Quick skimming through public documents shows, that CoP shift direction and magnitude is dependent mostly on aspect ration and sweep angle. Example graphs from this lectures (page 25) show aft shift of CoP for wings with sweep angle of less then 20-25 degrees approximately. If I was asked to visually estimate, how much CoP actually shifted from those airfoils, I would say it's just behind the middle of MAC for straight wing, and on the leading edge of MAC for 30 degrees sweep. Maybe 0.75 should be lowered to 0.2-0.5 or something, and that cosSweepAngle variable is a good candidate for inclusion in calculations. According to wikipedia, forward-swept wings also shift CoP forward on stall.

This NASA report on stall characteristics of swept wings is also a good source of data, page 28 gives good estimate of raw wing (without slats, wing fences and other cheeky things) behaviour. Generally: aspect ratio larger - CoP shifts further forward on stall. Same for sweep angle. Graphs also show, that it's common for CoP location to be outside of MAC in stall regimes for high-aspect ratio swept wings.

Unfortunately, those papers don't describe post-stall behaviour well, they usually stop on 30-40 AoA, but that "... * CosAoA " in your code should be a good enough approximation for what is omitted. Also, I don't think lateral CoP shift needs much attention.

Anticipating an obvious answer, containing a term "wing overhaul", I would like to ask for a bandaid instead. On the matter of "what to do with wings, composed of sections of stock panels, it will a bad estimation for those", I'd say it is the case even now and let it be so, but for some of us who use monolithic procedural wings regularily, this change while being quite simple, will also be "realistic". In the end, I just want my dank Suchkoi flips. Stock aero is quite bad at post-stall, it tends to have up to 4 equlibrium points in the span of 0-180 AoA, with Cm more resembling a sine with random noise applied.

Thanks for reading.

Edited August 4, 2016 by Boris-Barboris

[SilverWolf]

 

I think you guys need to rethink some of your equations.  Just as a rough example, the RJ's going to hit the barber pole (330,) thrust levers at idle, about 10 degrees nose down in about five seconds.  No airplane, save maybe a Cub, is going to fall out of the sky at 94 kias, not even a Cessna, so to get this kind of drag performance out of a swept-wing with a pair of CF34's hanging off the side is not very researchy.

My minor's in this stuff, guys; give me a call if you'd like me to crack open some notebooks.

[Boris-Barboris]

15 minutes ago, Verran said:

No airplane, save maybe a Cub, is going to fall out of the sky at 94 kias, not even a Cessna

It well may do with the mass of 8 tonns.

Edit: Or maybe I misunderstood, and you mean FAR applies too much drag?

Edited August 4, 2016 by Boris-Barboris

[ferram4]

@baldamundo: By damping I mean damping.  It reduces motion, like dampers do.  Or tries to anyway.

@Ourworldalpha1: Welp, then there's nothing I can do.  That requires mesh changes, and I can't fix part meshes in other mods.

@Vladokapuh: Well, FAR doesn't affect landing gear at all, so that means the only change is that you're hitting that ground harder with FAR or that you're getting a really high AoA after hitting the ground to get you back off the ground again.  There really aren't any other options.

@Boris-Barboris: Well, to start off with, the CoP moving off the wing is a thing that happens.  When you're looking to put a force center somewhere that allows all pitching moments to be handled by only lift and drag forces, if the lift or drag forces are very small they need a large moment arm to cancel the pitching moments.  Resulting in the CoP being placed somewhere completely off the vehicle.  Which is why the CoP is absolutely terrible for any discussions of stability and why FAR uses the aerodynamic center instead because at least by allowing a constant moment you get a force center that is somewhere reasonable.

The shift is based on the expected aerodynamic center shift for a 2d NACA airfoil in stall, which has it shift backwards.  While I suspect that adding adjustments for aspect ratio and sweep angle might be able to band-aid this somewhat, the fact is that fundamental flaws in the current sim mean that it will only get good behavior in very specific cases.  And it'll probably introduce bugs.  And then instead of spending time working on the already-delayed wing overhaul, I'll be fighting new bugs.  Just like the way that bugs have already prevented the wing overhaul from working.

I'll accept PRs to add band-aids, but I'm not going to spend lots of time tweaking, adjusting and bugfixing a system I'm planning to rip out.

@Verran: Uh... so I can't reproduce this issue myself using a basically identical setup, sans AJE, which leads me to believe AJE is the culprit, considering it has a way that it can cause this.  FAR has a bit of code that attempts to model the extra spillage drag from intakes when jet engines are heavily throttled down; normally it's not that much, although for very slippery planes it can double the drag on them.  Now, to get the spillage drag up high enough to raise the drag coefficient to 5.85 (!) AJE has to be increasing the "area" value of those intakes dramatically.  I'll look into what's going on there, but I suspect that it's AJE in some way.