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

[ferram4]

Configs for part mods are the responsibility of the part modders, not me. In any case, since all the space shuttle mods have always been designed specifically to work with stock aerodynamics, I seriously doubt that you will be able to get them to work with FAR, since the changes in aerodynamics may be enough to make them unstable.

Also, there is a search function. Google is also your friend. In fact, you probably would have found your answer in less time if you had started by searching.

[Kitspace]

Hello!

How is the strength of a joint between two structural parts calculated when it comes to aerodynamic forces that can rip that part of?

[Drew Kerman]

Anyone with any thoughts as to why my shielded part is ripping off from aerodynamic forces? http://forum.kerbalspaceprogram.com/threads/20451-0-24-2-Ferram-Aerospace-Research-v0-14-1-1-7-25-14?p=1436715&viewfull=1#post1436715

[ferram4]

@Kitspace: Based on a maximum force that any part can sustain in a direction based on its orientation, using a bunch of things specified in config files and the part's size.

@Gaiiden: Probably because it's not shielded for whatever reason. If the other parts are, but not that one, then it's probably got its origin outside the area that gets shielded and you'll need to adjust.

[Juncoph]

To demonstrate:

-snip-

Not sure what you mean. Winglets are wings where the entire wing is a control surface, they work best as rudders or canards, but if your aircraft is sufficiently small they could be your wing.

from my original post questioning winglets-

Question: do proper winglets (wingtips that get raised up/pushed down to reduce wingtip vortices) actually achieve their real-life counterpart's purpose, or are they more like small rudders, like in stock KSP?

[ferram4]

This is the inherent problem in KSP corrupting real-life terminology. Go yell at Squad about that, will ya?

Anyway, yes, they will help. Perhaps not to the same extent as in real life (they might be more or less effective than they should be, depending on the design), but they do help. This assumes that a significant portion of your drag is due to lift though.

[Juncoph]

This is the inherent problem in KSP corrupting real-life terminology. Go yell at Squad about that, will ya?

Anyway, yes, they will help. Perhaps not to the same extent as in real life (they might be more or less effective than they should be, depending on the design), but they do help. This assumes that a significant portion of your drag is due to lift though.

Alrighty then, thanks!

[Drew Kerman]

@Gaiiden: Probably because it's not shielded for whatever reason. If the other parts are, but not that one, then it's probably got its origin outside the area that gets shielded and you'll need to adjust.

Well, all 4 pods say they have 16 shielded parts, but only one breaks. I will have time to investigate further on Sunday.

[NecroBones]

I apologize if this is asked and answered frequently, but I have a quick question. I looked at the info on the OP, and I think I have all the answer I need, but I just want to be sure--

People are starting to ask if my mods work with FAR/NEAR. I'm telling them "yes", because as far as I can tell, everything looks OK. Is there anything special I need to do, for parts packs that don't include wings?

I have a general parts pack with fuel tanks, nose cones, and some radial parts that are fairly aerodynamic in shape. I'm assuming the collision mesh matters more than the model, but I don't know if that's accurate.

My second mod is a fairings set, using the stock engine-fairing module to create payload fairings. My test launches flew straight with FAR, at least until I intentionally staged the fairings at > Mach 1 to watch it tear apart.

Part of the reason I'm asking though, is that I have collision-mesh gaps to accommodate decoupling, since the nose-cones are optional and the fairings can be used "inline" with diagonal top surfaces. Here's an image, with lines drawn to show where the collision mesh edges are (below).

So I guess my question boils down to-- what determines how aerodynamic something is? The collision mesh? the model? This will help me in continuing to design these parts for compatibility.

http://ksp.necrobones.com/images/screenshots/fairing-meshes.jpg

Just wanted to make sure my question didn't get lost to the pages of time... Can anyone give a quick hint as to how aerodynamics are determined-- collision mesh vs visible model, and how gaps might effect it? Just trying to be mindful of people who will download my mods and use them primarily with FAR.

[nli2work]

Just wanted to make sure my question didn't get lost to the pages of time... Can anyone give a quick hint as to how aerodynamics are determined-- collision mesh vs visible model, and how gaps might effect it? Just trying to be mindful of people who will download my mods and use them primarily with FAR.

a very simplified visible mesh. Look in the debug log and you will see FAR generating drag models for each part during load time. gaps doesn't appear to significantly affect overall drag. The drag values are calculated per part far as I can tell, with exceptions you set in FAR config.

Edited September 29, 2014 by nli2work

[NecroBones]

a very simplified visible mesh. Look in the debug log and you will see FAR generating drag models for each part during load time. gaps doesn't appear to significantly affect overall drag. The drag values are calculated per part far as I can tell, with exceptions you set in FAR config.

Awesome, thanks!

[Drew Kerman]

@Gaiiden: Probably because it's not shielded for whatever reason. If the other parts are, but not that one, then it's probably got its origin outside the area that gets shielded and you'll need to adjust.

You're right - I checked and saw all instruments in the science pod were shield except the probe core.

However, I think you forgot that this was one probe out of 4 identical ones carried by the aircraft. They were all placed by symmetry so share the same design. Only one breaks off, which is what I'm finding to be most strange. I've flown around for several minutes at high speed and the the other three stayed properly attached. I've been messing around with several configurations and the problem persists. I did once actually have success leaving the runway with all 4 probes intact. I reloaded to launch and tried again, also success. Then the game crashed due to memory after several launch reloads and when I reloaded the game - the probe would rip off again.

Now, just today I noticed some new odd behavior. On the runway, in previous tests yesterday and Sunday, I could right-click on the science pods and see 16 parts shielded. Now, today all the sudden I get 0 parts shielded, and none of the parts that I've seen previously show up as shielded were shielded when I right-clicked them. It remains this way up until the point the one probe rips off (note FMRS up top showing the probe as "undocked") - then the parts shielded count comes alive. As demonstrated in this video:

My only recent game additions/updates were Action Groups Extended, ExtendedTrim and Ship Manifest. I removed all of them and tried the game again. Same behavior. I'm a bit perplexed. Here is the log file from the session shown in the video.

yes, this is 32-bit KSP

and yea, for now I'm just flying with aerodynamic stresses disabled

Edited September 30, 2014 by Gaiiden

[ferram4]

Yeah, known issue with the stable version of FAR, get the dev version from the github repo.

[NoClass]

Regarding wingtip winglets

Anyway, yes, they will help. Perhaps not to the same extent as in real life (they might be more or less effective than they should be, depending on the design), but they do help. This assumes that a significant portion of your drag is due to lift though.

Whoah?! Really? That's awesome! I guess I have no freaking clue how FAR actually figures out induced drag. Any chance you could explain that? (not actual induced drag, but FARs method)

[CaptainKipard]

The tutorial on github doesn't make it clear. How do I measure trapezoidal wings? Does the angle circled in green need to be negative in the calculations?

[undercoveryankee]

The tutorial on github doesn't make it clear. How do I measure trapezoidal wings? Does the angle circled in green need to be negative in the calculations?

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

That's correct. If the more common case of a swept-back trailing edge as shown in the tutorial is represented as a positive angle, then a forward sweep would be represented as negative.

[Plusk]

Hi, ive looked around last 50 pages and havnt found this reported. Not shure if FAR couses this issue, but here it is.

Test setup:

KSP 0.24.2 32bit Windows 7

FAR 14.1.1a

KV Rocketry 2.6c

Deadly Reentry Continued 5.3

Remote Tech 2

Inside a KW fairing i have a payload equipped with RT2 antena for atmosferic comms dp-10. It isnt suposed to snap, even more so - inside of an fairing. No cliping whatsoever (tested with 3.75m expanded fairing and a probe core). Its always breaking to aerodynamic stresses @ 240m/s up to 7km altitude. Ive also tried to placing it directly below the payload itself, to no avail. Looks like the fairing doesnt do anything. In 23.5, same setup, i was used to launch deployed antenas inside fairings and it was working fine.

So my question is, is it FAR (aerodynamic stresses) or KW (faulty fairings). RT2 cant be causing this, since stock parts are also afected. Further more, as the dp-10 snaps while unprotected, im myself partial to FAR, hence im reporting this here.

Do anyone have any ideas, or in case this was reported previously, point me to a fix? Thank you.

Edit on the fly:

Not to be called lazy, ive tested it without FAR, and everything works as suposed to. DP-10 not breaking inside/outside of a fairing @ 450m/s 1km alt, stock/RT2 deployed antenas inside fairing do break, but to g-force, not aerodynamic stresses (not breaking during normal, not crazy ascent). So it is FAR thats cousing this. Id apreciate any help, my whole space program is on hold due to this :/

Edit 2: Creating a 1.1TWR 10km/s dv monster rocket just to put 4t payload into LKO isnt a workaround, i dont have enough money, nor strong enough CPU for such damn thing

Edited October 3, 2014 by Plusk

[ferram4]

Use the dev version from the github repo. This issue was addressed on the previous page.

[Drew Kerman]

Use the dev version from the github repo. This issue was addressed on the previous page.

Or just turn off aerodynamic stresses if you don't like using dev versions

Also ferram, while most people don't adjust their default page length settings some do, so might be more accurate to say "x number of posts back" even if you have to guesstimate

[Plusk]

Use the dev version from the github repo. This issue was addressed on the previous page.

Will do, thank you On last page.. how embarasing Next time im going to search backwards.

[John FX]

So I just downloaded the dev version from the repo page and tried to launch a craft (solid 1st stage twr 2, 2000Dv) and my first stage got me to 12km with an an Ap of 17km at a speed of 350m/s.

This was disappointing to say the least.

I reverted to the last released version (14.1.1a) and launched the same craft and got an Ap of 62km at a speed of 1250m/s with the first stage.

Is this change meant to happen?

[Cerbis]

I'm planning out a mod and I'm wondering how FAR/NEAR would react to having the properties of a wing, e.g. lift and drag, change while a craft is loaded and in flight. Would it even be possible for FAR/NEAR?

Edited October 5, 2014 by Cerbis
Whee, grammar!

[ferram4]

@John FX: Yeah, messed up on a push to the repo. I'll get that fixed quick.

@Cerbis: It is possible, but bad things will probably happen. And it's on you to provide support for any issues with that.

[Cerbis]

What kind of bad things could I expect? What if the craft is stationary or not in atmosphere while the switching is occuring? I admit to not really having understood most of the FAR source, yet.

[smunisto]

Hey, Ferram. I think I may have some issue with FAR.

It hasn't done this before I started playing again about a month ago. I am using the latest official FAR version.

The issue in the game itself is that on certain actions(I have not been able to exactly reproduce when it happens), the UI starts blinking when moving the camera, or just straight out disappears. That is only the default UI elements, stuff like MJ windows does not disappear.

When this starts happening I open the KSP Debug window, and it is spammed with these: https://www.dropbox.com/s/8iudtqx7w9ck9zw/Screenshot%202014-10-05%2010.49.19.png?dl=0

Then, thecking the output_log I found these:

(Filename:  Line: -1)

ArgumentException: Value does not fall within the expected range.
  at ferram4.FARControlSys.OnDestroy () [0x00000] in <filename unknown>:0 

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

  at (wrapper delegate-invoke) Callback:invoke_void__this__ ()

  at (wrapper delegate-invoke) Callback:invoke_void__this__ ()

  at RenderingManager.OnGUI () [0x00000] in <filename unknown>:0 

EDIT: Forgot to mention, that quicksaving and reloading fixes the issue...until it appears again.

Edited October 5, 2014 by smunisto