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

[MAKC]

KSP 0.25, Win32. Entering 0 in the Mach speed field and clicking the button in the stability deriv tab causes FAR to crash.

[Castun]

Is there a guide for the realistic / ideal configuration of control surfaces?

[Wanderfound]

Is there a guide for the realistic / ideal configuration of control surfaces?

Not that I know of.

As rules of thumb, though:

* Elevators at extreme back and/or front, ailerons spread laterally near CoM, elevons only if you don't have a good spot for ailerons.

* More pitch authority at the back than the front.

* Enough control authority to make the plane do what you want it to, but no more than that; how much is too much is largely a matter of taste. Enough control authority to pull out of a steep dive at high altitude is also enough control authority to tear your plane in half at low altitude. High performance comes with an inevitable cost in tolerance for clumsy piloting; there's a reason we don't put learner drivers in Dodge Vipers.

[Van Disaster]

Is there a guide for the realistic / ideal configuration of control surfaces?

You can literally just look at a real plane & get an idea - just be aware modern combat aircraft are generally flown by computers with the pilot making suggestions, so they're less stable with more control authority than you really want to be messing with in KSP until you get a good handle on things.

There's no supersonic shock cone effects yet though so you can get away with a lot you wouldn't in a real plane

[Einarr]

Getting entries like these:

[WRN 17:44:33.968] [Part]: PartModule FARBasicDragModel at B9.Control.ASAS, index 1: index exceeds module count as defined in cfg.
Looking for FARBasicDragModel in other indices...
[ERR 17:44:33.970] ...no FARBasicDragModel module found on part definition. Skipping...

They show up both in the VAB/SPH as well as the Launchpad/Runway and affect almost every part of any given vessel that would normally use the module in question. I have not bothered checking parts that would not use this module as of yet (I can if asked to, but I've been combing through logs for awhile now and am tired of it).

I assume that since the drag model module is not being loaded for the majority of my parts that FAR will not work correctly.

These entries are from a recently (today) reinstalled stock KSP (after wiping the folder out), then reinstalled the mods I want. Yes, this is with the latest FAR as of this posting.

[camlost]

There's no supersonic shock cone effects yet though so you can get away with a lot you wouldn't in a real plane

Except there has been for almost 2 years

[ferram4]

@MAKC: Ok, I'll need to account for people who intend to do a simulation at velocity = 0. Of course, why would I expect someone to not do that?

@Einarr: Doesn't break anything, those PartModules shouldn't even be in the craft / save files to be loaded. Blame Squad for requiring all PartModules be saved and pummeling the log when it attempts to load them.

They have always done that. Nothing is broken, except Squad thinking that PartModules must be persistent no matter what.

[Einarr]

Ok then. I saw those while also trying to ferret out other issues I was having before the reinstall.

Also, don't forget to account for someone simulating at negative velocities. You know it will happen... *rolls eyes*

[Drew Kerman]

@Gaiiden: Well, nothing changed regarding aerostructural failure or forces applied in the recent update, so I don't know what's causing the issue. This is why you update quickly, because I have no idea where this issue might be coming from, since FAR 0.14.1 is old now.

play quickly actually, since I've kept FAR up to date within days of new releases just haven't had much time for KSP recently, let alone aircraft flight which I don't do often :/

I honestly didn't have much time to test before posting and leaving the computer for a few hours, but the cockpit falling off made me think of FAR structural failure first. The 0.25 node changes would have made sense in this case. I'll be doing some more testing tonight...

*some time later*

Okay so, it's definitely something about this cockpit part. I just don't know what. Nor is it related to FAR I don't think, because I switched off the option to enable aerodynamic failure and the part still went kaput on the runway. The F3 window said "Cl-130 Cockpit was ripped off by strong airflow". I tried changing the root part from one of the fuselage pieces to the cockpit itself, which made the cockpit not fall off (even when the aircraft had lifted into the air) but I still got the message and effects (control loss) of the cockpit getting ripped off - and all my engines overheated. Also, Deadly Re-Entry did not like it when the cockpit was ripped off yet still attached and spammed nullexceptions out the wazoo I removed DRE but that had no effect other than lack of log spam when the cockpit ripped off and yet didn't.

The definitive test was when I strapped on an NRAP test weight in place of the cockpit and the plane flew beautifully (yey, maybe I don't have to worry about those red derivatives after all...). I took off, flew the pattern, and greased her back onto the runway without an issue.

So, sorry to clutter the thread with what turns out not to be a FAR issue but since I'm already here, this is the part file of the cockpit section. Granted, this is an old part from 0.23 that hasn't been maintained by the author so it's not surprising something's screwy with it. Again tho, I can't figure out what it is. After the part cfg is the MM patch I apply to it.

Part.cfg

{
name = planeFuselageCockpitC
module = CommandPod
author = CoffeeSE

mesh = planeCockpitC.mu
scale = 1
rescaleFactor = 1.25

// definition format is Position X, Position Y, Position Z, Up X, Up Y, Up Z
node_stack_bottom = 0.0, -1.8001, 0.0, 0.0, 1.0, 0, 0

cost = 1500
category = Pods
subcategory = 0
title = CI-130 Cockpit
manufacturer = Coffee Industries
description = A high visibility cockpit with a lot of windows.
// attachment rules: stack, srfAttach, allowStack, allowSrfAttach, allowCollision
attachRules = 1,0,1,1,0

TechRequired = flightControl
entryCost = 4200
mass = 3.0
dragModelType = default
maximum_drag = 0.2
minimum_drag = 0.15
angularDrag = 2
crashTolerance = 50
breakingForce = 50
breakingTorque = 50
maxTemp = 3400
fuelCrossFeed = True

stagingIcon = COMMAND_POD
vesselType = Ship

MODULE
{
name = ModuleSAS
}

MODULE
{
name = ModuleReactionWheel

PitchTorque = 25
YawTorque = 25
RollTorque = 25

RESOURCE
{
name = ElectricCharge
rate = 1.05
}
}

CrewCapacity = 3

INTERNAL
{
name = C130Cockpit
}

MODULE
{
name = ModuleCommand
minimumCrew = 1
}

RESOURCE
{
name = ElectricCharge
amount = 100
maxAmount = 100
}
}

PART

MM patch

// carry antenna
// adjust node size
@PART[planeFuselageCockpitC]:FINAL
{
!MODULE[ModuleReactionWheel] {}
@mass = 2.75
@node_stack_bottom = 0.0, -1.8001, 0.0, 0.0, 1.0, 0, 2

MODULE
{
name = ModuleRTAntenna
Mode0OmniRange = 0
Mode1OmniRange = 2500000
MaxQ = 6000
EnergyCost = 0.13

DeployFxModules = 0

TRANSMITTER
{
PacketInterval = 0.3
PacketSize = 2
PacketResourceCost = 15.0
}
}

MODULE
{
name = ModuleSPUPassive
}
}

// lower the weight of the cockpit, remove the torque wheels

Bonus: During testing after the cockpit fell off, with full flaps and 66% throttle the aircraft took off and started looping itself. After the second loop I figured I'd better record the rest

Edited November 25, 2014 by Gaiiden

[Van Disaster]

Except there has been for almost 2 years

As far as I'm aware there's no shock cone off the nose which is meant to contain your whole aircraft ( I'm too tired remember what happens exactly if your wings poke out of the cone, but iirc it's rather awkward in several ways ), which means we can get away with long low-aspect winged spaceplanes. I'm not talking about the transonic changes in aerofoil surface flow.

I might be wrong and it's just kerbal materials being more incredibly OP than I thought.

[Hodo]

Farrem I have noticed something between the previous version and this version.

The CoL has shifted back on all of my previous designs made under 14.3 compared to 14.4.

It isn't slightly back its a ways back on some craft. Yet they fly the same as they did before?

[camlost]

As far as I'm aware there's no shock cone off the nose which is meant to contain your whole aircraft ( I'm too tired remember what happens exactly if your wings poke out of the cone, but iirc it's rather awkward in several ways ), which means we can get away with long low-aspect winged spaceplanes. I'm not talking about the transonic changes in aerofoil surface flow.

I might be wrong and it's just kerbal materials being more incredibly OP than I thought.

There certainly is. Just that with the engines being ridiculously OP, that's not really a concern

[ferram4]

@Gaiiden: Wild stab in the dark: since it has an RT2 antenna embedded in the cockpit, that's what's causing it to break off. It's set up using the breakable antenna criterion, not the unbreakable one.

@Hodo: I think I know what happened. Try the latest dev build and see if that fixes it.

[Hodo]

@Hodo: I think I know what happened. Try the latest dev build and see if that fixes it.

Will try it thanks.

[Aatch]

	Control surfaces can now be set to deflect in response to local AoA changes  
	Control surfaces are not On/Off for a given control direction; can be scaled from -100% to 100% for each

O.o

I wasn't sure what these meant, so I looked at the pull request from HoneyFox that implemented them. For those that can't read code, I'll elaborate:

The first point allows pitch-controlling surfaces to deflect some percentage of the current AoA, from -200% to 200%.

The second point simply scales effect of the relevant input. So at full pitch a control surface set to a Pitch % of 50 will pitch 50% of it's maximum deflection. Useful for elevons where you have too much pitch or roll authority, but not enough space to split into elevators and ailerons.

[Drew Kerman]

@Gaiiden: Wild stab in the dark: since it has an RT2 antenna embedded in the cockpit, that's what's causing it to break off. It's set up using the breakable antenna criterion, not the unbreakable one.

/facepalm wow I never even thought of how that would transfer over to the cockpit! Now that I look at it, I see the MaxQ property set in the module. I have no idea why this was never an issue in 0.24.2, probably a bug that got fixed in 0.25 or the latest RemoteTech release.

So yea, she flies like a dream, can takeoff with a .45 TWR and the cockpit stays attached now that I've removed the MaxQ property from the antenna. Thx!

[Streetwind]

Quick question:

I've installed a couple mods that add new airplane engines (Karbonite's propfans and such), and I looked at the FAR MM configs to figure out how they tweak the stock plane engines so can apply similar tweaks to the other ones. For consistency.

Now the stock turbojet for example has the following:

@velocityCurve
{
    @key,0 = 0 0.8 0 -0.00098
    @key,1 = 140 0.7 0 0
    @key,2 = 400 0.8 0.00049 0.00049
    @key,3 = 900 1 0 0
    key = 1800 0 -0.00098 0
}

And I'm a bit confused by the four parameters for each key. The first one is a speed, the second one I assume is a fraction of max thrust; but the third and fourth ones? What do they do, and do I need to specify them? Are they FAR-specific, or can you also use them in pure stock?

[BudgetHedgehog]

Specifies the shape of the curve so it's correct. Fine to use in stock. Search for KSP Float Curve Editor for more Info (pressed for time and on mobile here).

[Streetwind]

As time-pressed as you were, you told me everything I needed. Thanks!

[Hodo]

And Ferram that fixed the issue thanks. Now to figure out how to make an SSTO space plane that can haul 180tons to orbit in a single go.

[Wanderfound]

O.o

I wasn't sure what these meant, so I looked at the pull request from HoneyFox that implemented them. For those that can't read code, I'll elaborate:

The first point allows pitch-controlling surfaces to deflect some percentage of the current AoA, from -200% to 200%.

I'm still not quite sure what that's for. Is this a constant pitch deflection, or a max deflection limit? If it's a constant deflection, does it deflect to reduce AoA or increase it? If so, which way is positive and which is negative?

[HoneyFox]

Made an aircraft that tries to resemble F-16.

Yes, it's negative static stable.

With improved flight control system it can still do maneuver like this.

Watch the elevator deflect angle when doing a high-G turn.

Of course the brakes are installed too.

Some issues (at least I guess they are) I found:

1. The flaperon of this aircraft will stall very easily... It will stall even if we simply set the FLAP setting to 2 when doing a level flight. I don't know if it's because the flaperon is considered as a wing with small sweep angle and high aspect ratio but is not considered as part of the main wing.

2. The elevator stalls easily when under a medium AoA. AFAIK the downwash effect of the main wing is not simulated in FAR currently right? So that would be expected. In RL, according to some material written by BMS (a high-fidelity simulation game for F-16) developers who have been studied F-16's FLCS a lot, its elevator will stall when the aircraft has ~25 deg AoA + its deflect angle 25 deg (i.e. local AoA if we don't consider the downwash will be ~50 deg). That's quite a big difference compared to the current FAR case.

3. The leading-edge slats doesn't seem to increase the critical angle of the main wing, but that might be because it's just a subtle change or perhaps it's because they are all procWings and might have some glitches somewhere?

Edited November 26, 2014 by HoneyFox

[AccidentalDisassembly]

Posted this in the TS thread too, but then remembered Biotronic isn't around too much and thought it might be good to post it here too. Having some kind of issue, possibly with TweakScale & FAR interaction - I'm using TweakScale 1.44 and the newest FAR (1.44 because 1.47 is broken).

This time the issue occurred, it was on reloading KSP, going to SPH, loading craft (that was already on the runway), launching. Logspam of nullreferenceexceptions related to TS and FAR + very, very slow performance.

The previous time the issue occurred, I had launched the same craft, flown far from KSC, and then returned - it *seemed* to happen, maybe, when certain parts of KSC re-loaded or when some debris re-loaded near KSC or something like that, but I am not sure.

Prior to that, the same thing happened after launching a craft, reverting to the SPH, and then launching again... or something along those lines.

Here's a log: https://dl.dropboxusercontent.com/u/59567837/output_logFARandTS.txt

EDIT: reverting to 14.3.2 seems to fix it so far...

Edited November 26, 2014 by AccidentalDisassembly

[Streetwind]

Okay, so I'm toying with the curve editor in Unity. Spiffy!

However while I was looking at examples of curves from FAR, I noticed something that just might be a bug of the most trivial kind

The basic jet engine tweak says: @key,2 = 350 -0.005 0 0

But shouldn't it be: @key,2 = 350 0 -0.005 0

All the other engines are set up that way, and the curve looks better too... not to mention that negative thrust seems a bit silly

The effect of this bug basically makes the basic jet engine fall off much more sharply in thrust above 250 m/s than it would with the adjusted curve, making its top speed slightly lower than intended. 8% thrust at 300 m/s instead of 15%.

Edited November 26, 2014 by Streetwind

[Hodo]

Made an aircraft that tries to resemble F-16.

Some issues (at least I guess they are) I found:

1. The flaperon of this aircraft will stall very easily... It will stall even if we simply set the FLAP setting to 2 when doing a level flight. I don't know if it's because the flaperon is considered as a wing with small sweep angle and high aspect ratio but is not considered as part of the main wing.

2. The elevator stalls easily when under a medium AoA. AFAIK the downwash effect of the main wing is not simulated in FAR currently right? So that would be expected. In RL, according to some material written by BMS (a high-fidelity simulation game for F-16) developers who have been studied F-16's FLCS a lot, its elevator will stall when the aircraft has ~25 deg AoA + its deflect angle 25 deg (i.e. local AoA if we don't consider the downwash will be ~50 deg). That's quite a big difference compared to the current FAR case.

3. The leading-edge slats doesn't seem to increase the critical angle of the main wing, but that might be because it's just a subtle change or perhaps it's because they are all procWings and might have some glitches somewhere?