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

[sarge38]

This didn't work, one thing i noticed though is that when i turned on visuals the wings seem to be stalling, although before the update they weren't. it also seems that all the control surfaces are stalling even when im not moving very fast (200/300km/h) where again, before the update none of this happened. Also, the control surfaces seem to travel slower between positions... very frustrating as i use to fly this thing with my joystick.

Sadly this is happening with every fighter I build, from light to really heavy. Im using a cranked delta design and my CoL is right behind the CoM, although that shouldnt be an issue as the wings are randomly stalling out. this also happens with control surfaces

[blowfish]

This didn't work, one thing i noticed though is that when i turned on visuals the wings seem to be stalling, although before the update they weren't. it also seems that all the control surfaces are stalling even when im not moving very fast (200/300km/h) where again, before the update none of this happened. Also, the control surfaces seem to travel slower between positions... very frustrating as i use to fly this thing with my joystick.

A lot of the wing code was modified in a recent update (last month maybe). It definitely changed the way some things fly, and even required some major redesigns as previously stable designs became unstable due to wings generating different amounts of lift.

[dharmdevil]

All my previous designs are now not working too. I tried to make new planes with the same design principle as I did with my previous ones and they all fly like a piece of paper. Then I noticed that putting wing angles and putting the CoL above CoM like I used to(to make it stable) are the culprit. I made a new one without lifting the CoL above and it flies OK, but not as beautifully as it was before. I also use SAS on precision ascent and re-entry(the only time I use it) before and now it just jerks up and down no matter how stable your plane is.

[DaMichel]

Or are you behind this, ferram4?

[Wanderfound]

This didn't work, one thing i noticed though is that when i turned on visuals the wings seem to be stalling, although before the update they weren't. it also seems that all the control surfaces are stalling even when im not moving very fast (200/300km/h) where again, before the update none of this happened. Also, the control surfaces seem to travel slower between positions... very frustrating as i use to fly this thing with my joystick.

Screenshots time: post FAR stability analyses, at 0m/Mach0.35, 25,000m/Mach5, 30,000m/Mach6. We can probably sort out your issues, but not if we can't see what we're working with.

[ferram4]

@sarge38: Without knowing what you've updated from, I can't tell what the problem is. Most of the wing code hasn't changed since 0.14.3, which means you shouldn't be having any problems at all, assuming you nuked the FAR folder as required.

Control surfaces still deflect at the same speeds, nothing has changed there in a long time. Finally, speed has nothing to do with whether a surface stalls, only angle of attack; sounds like you need more control authority or to decrease the plane's stability.

@dharmdevil: Define "fly like a piece of paper." I have absolutely no idea what your complaint is.

[theend3r]

My planes sometimes behave strangely - experiencing roll while pitching - but at other times they fly perfectly. I suspect I may be a victim of this:

I believe I have fixed what I can from my end. The missile can still sometimes stop tracking if you switch to it because of a FAR bug that throws a stream of null reference exceptions when switching vessels. Ferram4 has already fixed the issue but has not released a compiled version yet.

Is it true? Is there some dev release which has tis fixed?

[blowfish]

Is there some dev release which has tis fixed?

On Github - click on the source link in the OP and download the GameData/FerramAerospaceResearch folder.

[dharmdevil]

@sarge38: Without knowing what you've updated from, I can't tell what the problem is. Most of the wing code hasn't changed since 0.14.3, which means you shouldn't be having any problems at all, assuming you nuked the FAR folder as required.

Control surfaces still deflect at the same speeds, nothing has changed there in a long time. Finally, speed has nothing to do with whether a surface stalls, only angle of attack; sounds like you need more control authority or to decrease the plane's stability.

@dharmdevil: Define "fly like a piece of paper." I have absolutely no idea what your complaint is.

Just like how a piece of paper falls down after you throw it into the air; all my old planes with wings angled upward or with CoF above CoM flies sideways like a pendulum in a randomly until it flips, they all flew exceptionally well at 0.24.

[Wanderfound]

Just like how a piece of paper falls down after you throw it into the air; all my old planes with wings angled upward or with CoF above CoM flies sideways like a pendulum in a randomly until it flips, they all flew exceptionally well at 0.24.

As before: if you post some screenshots of the analysis screens, we can work out what you need to do to fix it. It is most likely a mass-balance issue; all of your ships are likely to have their CoM further back than they used to (because all of your wings and control surfaces are much heavier), reducing the power of the rearset horizontal and vertical stabilisers.

The jerky SAS is a KSP problem rather than FAR; stock SAS code is much too sensitive for high control authority craft, and it got worse with the last update. A PID tuner such as the one included in the http://forum.kerbalspaceprogram.com/threads/100073-0-25-Pilot-Assistant-Atmospheric-piloting-aids-0-9-1-2-%28Dec-7%29 mod can fix it. Cutting the kp values to 1/3rd of default generally works for me.

[Hodo]

Just like how a piece of paper falls down after you throw it into the air; all my old planes with wings angled upward or with CoF above CoM flies sideways like a pendulum in a randomly until it flips, they all flew exceptionally well at 0.24.

Sounds like you are having an SAS and CoM vs CoL issue.

As Wonderfound said the SAS after .24 became REALLY twitchy and you should get the PID tuner or Pilot assitant tool, those help a great deal with cutting that issue down. Next check your CoM vs your CoL, I know .25 messed up a few of my old designs some how, but it wasnt a huge deal to fix them. It was a slight shift in the mass of some parts.

[Peregrinuus]

For some reason, FAR doesn't show up when I'm launching from the launch pad in 64 bit. I'm unsure if this is a related issue, but my control surfaces have no effect either, resulting in aerodynamically unstable rockets that always spin out of control. Also trying to toggle the CoL in the VAB seems to not work at all.

[Master Tao]

@Peregrinus:

Please read the OP of every mod you use:

Note: This mod disables itself on 64-bit Windows builds of KSP to avoid exacerbating its inherent instability. Users are encouraged to switch to either the 32-bit Windows build or the 64-bit Linux build, which are far more stable.

This post in the General Add-on Affairs forum gives more information.

[Peregrinuus]

@Peregrinus:

Please read the OP of every mod you use:

This post in the General Add-on Affairs forum gives more information.

Sorry, I've been using FAR since I can remember and I was a big time user of 64-bit KSP up until a few months ago when I stopped playing KSP.

[AccidentalDisassembly]

I'm getting a bunch of this in me logs:

NullReferenceException: Object reference not set to an instance of an object

at SpriteText.UpdateMesh () [0x00000] in <filename unknown>:0

at SpriteText.set_Text (System.String value) [0x00000] in <filename unknown>:0

at ferram4.FARControlSys.ChangeSurfVelocity (SurfaceVelMode velMode) [0x00000] in <filename unknown>:0

at ferram4.FARControlSys.LateUpdate () [0x00000] in <filename unknown>:0

(Filename: Line: -1)

By a bunch, I mean thousands of instances. Does it mean anything? I really couldn't say what the circumstances were, it was just thousands of that NRE spamming before a crash that I *thought* was due to being out of memory (and probably was...?). Here's the log just in case: https://dl.dropboxusercontent.com/u/59567837/output_logFARstuff.txt

FAR 14.4 and a bunch of other mods.

[sarge38]

@sarge38: Without knowing what you've updated from, I can't tell what the problem is. Most of the wing code hasn't changed since 0.14.3, which means you shouldn't be having any problems at all, assuming you nuked the FAR folder as required.

Control surfaces still deflect at the same speeds, nothing has changed there in a long time. Finally, speed has nothing to do with whether a surface stalls, only angle of attack; sounds like you need more control authority or to decrease the plane's stability.

@dharmdevil: Define "fly like a piece of paper." I have absolutely no idea what your complaint is.

I had updated from 14.2, im uploading the stats of the aircraft and pictures of the CoL and CoM

[sarge38]

I had updated from 14.2, im uploading the stats of the aircraft and pictures of the CoL and CoM

Here are the pics

http://imgur.com/a/fzusy

http://imgur.com/a/lMlYO

[BahamutoD]

Here are the pics

http://imgur.com/a/fzusy

http://imgur.com/a/lMlYO

Do you have the latest version of the Mk.2 Lightning cockpit? It has the required a FAR config to work properly. Without it, it has a ton of drag.

[Hodo]

Here are the pics

http://imgur.com/a/fzusy

http://imgur.com/a/lMlYO

Here are my quick assessments of that craft.

It is a good design but you are having some issues with the red numbers there. Looks like your craft is losing a bit of yaw control at low speeds. And you have some serious side slip issues at mach 1 at 25km. I would almost suggest canting your tail out a bit more, it may fix all of that. I would also ad a bit more wing to the craft, mainly at the tip or give them a bit more of an angle to them this should help a bit with your higher speed performance issues.

Otherwise those are great looking fighters, and look like they would be quite agile.

[Wanderfound]

Here are the pics

http://imgur.com/a/fzusy

http://imgur.com/a/lMlYO

Okay...

First up, most of your wing surface is behind CoM, so the increased mass will have shifted CoM backwards, closer to CoL. This is why you're getting pitch-up problems at altitude (the red numbers in the "Down Vel Derivatives" bit). The horizontal stabilisers of the tailplane no longer have sufficient leverage to hold the nose down in thin air.

To fix this, you need to increase the power of the tailplane, or reduce the lift in front of CoM. You can increase the power of the tailplane by making it bigger, but you could also do it by increasing the distance between the tailplane and CoM. You can do this by either lengthening the fuselage or shifting some weight forwards.

The easiest way to shift weight would be to lighten some of your wings. At present, they're set at default toughness (I assume) of 1.0. This is more than strong enough for anything short of vigorous and determined suicidal flying. 0.6 will still allow high-G aerobatics, and 0.3 is plenty strong enough to go to space if you fly carefully.

If you'd rather keep the super-tough wings, you'll need to either add some weight up front, make the tailplane bigger, extend the tail or strip the strakes from the front of the wings. One of these solutions alone may not sort it, but a few in combination should get your numbers green.

You're also getting roll problems at moderate altitude while flying (relatively) slow. This are the red numbers in the Lateral Derivatives. You may choose to deal with that by just gaining some speed before climbing, but if you want to slow cruise in thin air you'll need either longer wings or a bit of dihedral. Angling the tailplane tips up by 10° or so would probably sort it.

[samuelscott]

Awesome plugin! Keep up the good work.

[sarge38]

Okay...

First up, most of your wing surface is behind CoM, so the increased mass will have shifted CoM backwards, closer to CoL. This is why you're getting pitch-up problems at altitude (the red numbers in the "Down Vel Derivatives" bit). The horizontal stabilisers of the tailplane no longer have sufficient leverage to hold the nose down in thin air.

To fix this, you need to increase the power of the tailplane, or reduce the lift in front of CoM. You can increase the power of the tailplane by making it bigger, but you could also do it by increasing the distance between the tailplane and CoM. You can do this by either lengthening the fuselage or shifting some weight forwards.

The easiest way to shift weight would be to lighten some of your wings. At present, they're set at default toughness (I assume) of 1.0. This is more than strong enough for anything short of vigorous and determined suicidal flying. 0.6 will still allow high-G aerobatics, and 0.3 is plenty strong enough to go to space if you fly carefully.

If you'd rather keep the super-tough wings, you'll need to either add some weight up front, make the tailplane bigger, extend the tail or strip the strakes from the front of the wings. One of these solutions alone may not sort it, but a few in combination should get your numbers green.

You're also getting roll problems at moderate altitude while flying (relatively) slow. This are the red numbers in the Lateral Derivatives. You may choose to deal with that by just gaining some speed before climbing, but if you want to slow cruise in thin air you'll need either longer wings or a bit of dihedral. Angling the tailplane tips up by 10° or so would probably sort it.

Thanks, ill use this on the first aircraft, but i hadn't updated procedural wings in a while, turns out that's why the first plane wasn't working. Otherwise trying this out on the first plane made it preform ten times better, although nowhere near the 15g's the second plane can pull! thanks for the reply.

[Hodo]

Thanks, ill use this on the first aircraft, but i hadn't updated procedural wings in a while, turns out that's why the first plane wasn't working. Otherwise trying this out on the first plane made it preform ten times better, although nowhere near the 15g's the second plane can pull! thanks for the reply.

You would be surprised at how strong the default wing strength is. I have built light weight fighters that can pull well over 15Gs and kill the pilot, thanks DRE. But the default strength may not be strong enough for heavy aircraft, and you may need to strengthen the wing a bit.

[Lei07]

Bump for post #6989 http://forum.kerbalspaceprogram.com/threads/20451-0-25-Ferram-Aerospace-Research-v0-14-4-11-24-14?p=1587285&viewfull=1#post1587285

[kcs123]

Bump for post #6989 http://forum.kerbalspaceprogram.com/threads/20451-0-25-Ferram-Aerospace-Research-v0-14-4-11-24-14?p=1587285&viewfull=1#post1587285

It seems that you bumped in similar bug as I described in Procedural Wing thread. I'm not sure if it is related to FAR, Tweakscale, Procedural Wings or some other mod.

Based on your pictures, your CoL is shifted slightly. That is main reason why you don't have same L/D ratio on previous and updated craft. When you run game and load your save game try to load craft in SPH editor twice in a row to see if there is CoL shifting bug present.