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

[Deejay2000]

Hell yeah.

[illectro]

@illectro: Yeah, unfortunately FAR's drag calculation seems to grab the deployed state of those transmitters, I'm not sure exactly why though.

As for the fairing thing, what FAR does ever time the vessel part list is updated is it goes through all of the fairing parts, calculates their bounds, and then goes through the list of every part in the vessel to see if that part's origin is inside the fairing (for wings it also checks the wingtip for thoroughness, or it's supposed to; that doesn't seem to work either for some reason). So the only way the issue you're seeing should happen is if the transmitter wobbles outside the fairing at the same time as you're ditching a stage. FAR isn't calculating if something is inside the fairing every single frame, that would add lots of vector math, comparisons and iterating through part lists that are simply unnecessary. Try right-clicking on the transmitter and making sure that it stays "isShielded = true" the whole way, since that needs to be false in order for FAR to apply drag parameters; it acts the same as FAR detecting zero density and it simply stops running the rest of the code at that point.

If the payload is wobbling too much, I'd make sure you're running KJR v2.0 rather than an earlier version if you don't want to wait until the official joint fixes. Things have gotten a lot better since the earlier versions of KJR.

But anyway, the video will be good; video documentation of bugs is great, because then I can actually see everything that went wrong.

It's not related to staging, but I can see in the FAR flight details that the terminal velocity goes from 500+m/s to 2 m/s the instant before the rocket tears itself apart, it's a really curious behaviour.

[MAKC]

0.13 bug:

Noticeable FPS decrease when aerodynamic center is on. Log says "FAR Error: Aerodynamic force: NaN at *random parts*

Edit:

Also, negative Cl numbers on parts in flight.

Edited March 15, 2014 by MAKC

[ferram4]

@illectro: Then it's starting with a structural failure somewhere; perhaps the payload is breaking, and then that puts it "outside" the fairing, since the fairing doesn't check other vessels, and then everything goes to hell from there. Moar struts, less acceleration, less aggressiveness.

@MAKC: I know about the AC in editor bug, I'm trying to track that down. The Cl numbers are correct as well, body lift can be very strange in some cases.

[theSpeare]

What's the changelog for the experimental?

[NathanKell]

Ooh, an experimental!

Also, FYI: you probably need to do the same thing you did for the Mercury retro straps/decoupler to the Firespitter wing-mounted folding gear. I'm getting quite insane drag for them even when they're retracted. Since, when retracted, they're flush with the wing, I gave them the same next-to-nothing drag model, and suddenly my Swift can perform like the Sabre it looks like.

[ferram4]

@theSpeare: It's in the readme, but I'm not going to add it to the main post's changelog until it's integrated into a fully stable release. Here it is repeated though:

CHANGELOG:0.13x1v------------------------------------
Features:
Integrated numerous code optimizations and fixes from a.g.
Rearward-facing tapered parts will produce less drag at hypersonic speeds, as they should; this may affect the stability of some designs
Implemented more exact tapering drag based on cones rather than parabolas
Wing sweep is better accounted for in multi-part assemblies
Updated to Toolbar v1.7.0

Tweaks:
Reduction in skin friction drag to more proper levels
Some changes to control surfaces to make them play better with SAS

Bugfixes:
Fixed a typo in the config that would allow turboramjets to accelerate without limit

@NathanKell: I'll look into it.

[Themorris]

Fixed a typo in the config that would allow turboramjets to accelerate without limit

Wasn't that a feature?

[paju1986]

Hello Ferram. First of all i want to say thanks for this great plugin. I'm using it with realims overhault and im trying to build my first successfull SSTO skylon-like.

The problem i have is that the cargo bay i'm using seems not to shield parts properly. I'm using Wolft's pack cargo bays because them fit perfectly with a 5m version.

http://forum.kerbalspaceprogram.com/threads/47701-0-21-Wolf-Pack-Aeronautics-V1-2-Parts-Pack-(Updated-Aug-30-2013)

They must have some compability issue with FAR.

Here some pictures of my SSTO. The maximum altitude i reached was 40 km and the cargo explodes because of the heat because it is not protected.

[Boamere]

Hello Ferram. First of all i want to say thanks for this great plugin. I'm using it with realims overhault and im trying to build my first successfull SSTO skylon-like.

The problem i have is that the cargo bay i'm using seems not to shield parts properly. I'm using Wolft's pack cargo bays because them fit perfectly with a 5m version.

http://forum.kerbalspaceprogram.com/threads/47701-0-21-Wolf-Pack-Aeronautics-V1-2-Parts-Pack-(Updated-Aug-30-2013)

They must have some compability issue with FAR.

Here some pictures of my SSTO. The maximum altitude i reached was 40 km and the cargo explodes because of the heat because it is not protected.

http://i.imgur.com/KP3DEcZ.jpg

http://i.imgur.com/k768g3f.png

http://i.imgur.com/3h1ojVk.jpg

Are they named correctly? because if the cargo bays don't have the correct name they won't work (i can't remember exactly what word they need)

[illectro]

@illectro: Then it's starting with a structural failure somewhere; perhaps the payload is breaking, and then that puts it "outside" the fairing, since the fairing doesn't check other vessels, and then everything goes to hell from there. Moar struts, less acceleration, less aggressiveness.

I did a test for this hypothesis, I reasoned that if this were the case then reducing the drag on the part would reveal the breakage due to the acceleration without the rest of the associated destruction. With drag set to a much smaller level nothing on the rocket breaks. Is this a reasonable experiment.

[paju1986]

Are they named correctly? because if the cargo bays don't have the correct name they won't work (i can't remember exactly what word they need)

It was not named correctely but i changed the name to contain "Cargo Bay"... now i saw in the config file that it is managed as a cargo bay correctly but still it doesnt shield the parts...

In the context menu it says "shielded parts: 0". I think that can be mayble a problem with the animation system it is using but i dont know a lot about that....

[ferram4]

@paju1986: First off, if it's exploding from overheating then that's a DRE problem, and FAR doesn't interface with DRE in any way. Nothing you try to change in FAR will fix that. As for the cargo bays, check to see if parts are shielded when the bay is open; that might mean that something is happening backwards for some unknown reason. It is a fairly out-of-date part, perhaps that is part of the issue.

@illectro: Do you mean the stock drag parameters in the config file? Those are zeroed out completely by FAR, and so you effectively didn't change anything; your results are likely a sort of "piloting placebo effect," where you pilot better after making the change and thinking it will help. As a test of my own, I launched that deployable array many times in a payload fairing and saw no sudden rocket dis-assembly due to the payload, but I did find out why the part has so much drag: apparently when deployed the widest end has an equivalent radius 8 times that of the attachment end, and the tapering of the part over a very short distance is the cause of the issue. I've made a few changes that should allow FAR to quickly recalculate the shape of parts if it can properly detect that the part has an animation module, so that'll come in the next full update.

So the short answer is that your experiment is likely invalid due to the way FAR functions unless both launches were run on autopilot and followed the exact same trajectory with the exact same longitudinal and lateral forces on the payload.

[a.g.]

@paju1986: As for the cargo bays, check to see if parts are shielded when the bay is open; that might mean that something is happening backwards for some unknown reason. It is a fairly out-of-date part, perhaps that is part of the issue.

One thing is that currently FAR requires cargo bay doors to have colliders - if things can go through them, and you can click on cargo with them closed, then FAR will think they are never closed. This is the case with the MK2 B9 cargo bays. The reason for the requirement is that parts aren't consistent re which end of the animation is open, so FAR does raycasts to find out.

[BananaDealer]

So I've run into a bit of a problem while testing my "WhiteBird" SSTO design...

The craft itself flies perfectly well, a bit of side-slip regardless.

However, once I add my "Atlas" S/P Truss Segment into its' bay... The craft experiences massive G-load (even though the G-Force bar on the navball is always in the green) and something derpy happens and the thing just flies off camera and explodes somewhere in the distance.

My suspicion is that FAR is having trouble calculating Stability Derivatives as this is what I get on that screen, no matter what I put in as Temp, Density or Mach:

Here's the thing for the WhiteBird without a payload, derived for Mach 2:

And here's what the payload in question looks like:

And just for fun, here's sacrificing Bill and Bob to the issue:

Javascript is disabled. View full album

Any help would be welcome...

[acc]

I had this bug too, but with the structural part from the procedural parts. after updating the pack the bug was gone. I think something with the truss part is wrong.

Every launch vehicle with this part had exacly the same bug at 6km.

[Andrewmacor]

Quick question...

So Every time I put a heat shield on a capsule or anything, flips upside down, putting the heat shield looking retrograde instead of prograde to protect whatever. I dont use deadly reentry but i like to use heatshield to simulate. Please help!!!

[BananaDealer]

I had this bug too, but with the structural part from the procedural parts. after updating the pack the bug was gone. I think something with the truss part is wrong.

Every launch vehicle with this part had exacly the same bug at 6km.

Hmm... It might be Lack's cargo bays not having their drag characteristics properly set up and causing FAR to freak out... Though it doesn't explain why I was able to lift up the first segments, which are made out of LLL bays as well and not this...

Edit: Definitely a problem on FAR's side... Made a Truss Structure using Nothke's S6 rings and the same thing happens...

Edited March 18, 2014 by BananaDealer

[pingopete]

ok so finally got my shuttle into space and just about re-enterable (RSS+RO etc), however my RS-25D's (SSME's) produce obscene amounts of drag, sometimes as much as 450-500 units when travelling at just 200 m/s ASL. It basically makes my shuttle stall and impossible to glide. I've got an air plate beneath the engines for authenticity although it doesn't help with engine drag at all. I've tried editing both JB's real engines config and the original Nova punch cfg with no luck, I finally tried adding an exception in the FAR config but again with no notable difference to the drag :/ I don't suppose anyone else has had this problem and might know what's wrong? Every other aspect of FAR and my other parts all behave normally.

Any help or ideas would be greatly appreciated!

[Boamere]

ok so finally got my shuttle into space and just about re-enterable (RSS+RO etc), however my RS-25D's (SSME's) produce obscene amounts of drag, sometimes as much as 450-500 units when travelling at just 200 m/s ASL. It basically makes my shuttle stall and impossible to glide. I've got an air plate beneath the engines for authenticity although it doesn't help with engine drag at all. I've tried editing both JB's real engines config and the original Nova punch cfg with no luck, I finally tried adding an exception in the FAR config but again with no notable difference to the drag :/ I don't suppose anyone else has had this problem and might know what's wrong? Every other aspect of FAR and my other parts all behave normally.

Any help or ideas would be greatly appreciated!

Screenshot of it happening?

That would help!

[pingopete]

Screenshot of it happening?

That would help!

Here's a video, although I managed to put it down ok it was at a near vertical decent with roughly 600kn of force slowing me down from the SSME's.

Just as a reference at the very most the shuttle's other parts will produce around 20kn of drag at these speeds and altitude.

If anyone knows a way of even just disabling the drag model for the engines I'd be happy

P.s. I don't know how to share public screen shots from dropbox, they just appear as little square icons.. hence the video

Edited March 18, 2014 by pingopete

[ferram4]

@BananaDealer: Bug reports like that without a copy of the output_log.txt aren't much use. I have no idea what's breaking, only that something's breaking and that I've never seen that issue before. Post the log (not KSP.log) and we'll see if anything useful can be found in it.

@Andrewmacor: Is the reentry vehicle tall and narrow? Then that's intended behavior; you'll note that no real life reentry vehicles are like that. You need the reentry vehicle to be short and squat with as much mass right behind the shield as possible.

@pingopete: Config.xml: change sonic additional drag to 0.2, change incompressible drag to 0.01, change node scale factor to 1. The back end of things makes more drag to make them more stable in stock KSP compared to real life.

[pingopete]

thanks, I'll post this on the vid

[Azimech]

"Wing sweep is better accounted for in multi-part assemblies"

Wow, that suggests that my swing wing F14 would actually make sense now!

[John Crichton]

Holy batman!!! I went from "mhhhh, I'm pretty decent at KSP" to "god I'm such a donkey"