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

[Sevio]

Sevio, did you try putting another command pod or probe on the ship and selecting "control from here" on it?

Or tried docking and going for reentry without selecting "control from here" on the docking port?

The control change seems to be the issue.

The control change may have played a factor but the navball is showing the right orientation. It never showed the wrong one either, I just did "control from here" on the cockpit to make sure. I'm more and more convinced this is a bug related to FAR's handling of the control surfaces, as without FAR they work fine under the same docking & reentry procedure. I've quickloaded and redone the reentry half a dozen times over by now trying different ways of getting the control surfaces to work right. (setting control, going to space center and coming back after undocking, quitting the game and reloading after undocking, etc)

From what I could see in the FAR flight data on the previously linked screenshots, it's almost like FAR has the up/down direction of the plane flipped. It's showing negative L/D and Cl. Also there is the glitch where the UI rapidly toggles on and off while the error log is being spammed, which also doesn't happen without FAR.

Some additional info about the plane: The fuel tank that I left behind at the station was attached to a surface mounted docking port on the cargo bay, facing backwards and upside down. After undocking that port probably became the root part, maybe this is why FAR interprets control surface input the wrong way?

Original description of the problem

Edited August 2, 2014 by Sevio

[Ventman]

Not totally sure if this is a bug or not but when I have parts attached radially to a rocket their drag mainly pulls the rocket to one side, making it very difficult to launch things straight without stacking them with reaction wheels. I've tried reinstalling FAR, verifying KSP file integrity through steam and removing all other mods (except for MM) but the problem persists, if it is in fact a problem and not something I just didn't notice in the past.

I don't know if it helps at all, but here's some screenshots of the CoL being weird http://imgur.com/a/zIb7Y and an output log https://www.dropbox.com/s/ov839zab6f1zci6/output_log.txt.

I have kind of the same problem. Some 2,5m parts (MK1-2 Command Pod, Rockomax Brand Adapter or Rockomax Brand Adapter 02 for example) shift the center of lift of my rocket to one side. Tanks, engines and other 2,5m parts on the other hand are working fine. I tried it with FAR and NEAR with the same result.

Does anyone have an idea what could cause this or has a solution? Would be much appreciated.

[tetryds]

Did you try setting "control from here" again on the cockpit before ejecting the tank with the docking port?

That's a weird issue, let's wait for Ferram.

[Ventman]

Yep, tried that but the issue persists.

[ferram4]

@Sevio: That's probably something to do with the difference between the transform of the new vessel root part (the docking port) and the part you're controlling from (the cockpit). I'll look into finding a fix. I'll probably just have to run the control orientation code again, no big deal.

The exceptions are due to a bug that I've already fixed for the dev build; that should be out whenever I fix this one.

@Ventman: That's what happens when the change in orientation results in drag in almost exactly the same direction.

That's it, the vector from the CoL is confusing people, I'm getting rid of it. It's a point anyway, and you don't need the vector.

[StevenJ]

TeiwazVIE: Get Firespitter and use the alignment guides to perfectly align your wheels. KSP has a giant honking known issue with unaligned wheels causing planes to skitter all over the runway and go boom.

But the other serious issue is that your takeoff speed is going to be insanely high because your main wheels are so far back from your COM, and even with perfectly aligned wheels, KSP *does not like* high speed on the wheels. Of course, you also have the wing loading of an F-104, so that doesn't help either, but the main fix will be to place your main wheels *right* below your AC, slightly back from the CoM. That will let you takeoff at maybe 100-120m/s? (aka 220-250 mph).

I know this is a few days late but yes I agree 100% with what you wrote. The landing gear on that design is all wrong. It shouldn't have them soo far back and then yet another pair on the wings ahead of COM. I'd do exactly that, place the wheels a few meters behind the COM and that should work. Also I'd ditch the tailfins for real elevators and replace them with canards of some sort. I'd also add controls surfaces for flaps and ailerons on the wings. I got to say this new version of FAR is better than the prior ones. My airplane designs are more stable and tend to be over stressed less. I did want to ask a question to the mod creator. Did you make it so that way the in game flight computer will stop pulling or turning when it senses fractl density becoming too high? In 23.5 I'd easily be able to tell my plane to pull so hard past fractl density but now in 24.2 the planes I'm flying with FAR seem to back off automatically under stressful aero dynamic maneuvers.

[taniwha]

ferram4: While I approve of the move, I suspect you'll get a flood of complaints about FAR breaking the CoL indicator :/

On a separate note: I used a rather tall tail-fin on my delta-wing plane last night and had some issues with roll/yaw stability. I take it having a tail-fin nearly as tall as your delta-wing is wide (from the center of the craft, not tip-to-tip) will lead to problems due to the torque from the yaw inducing roll.

Also, I'm not sure what it was though I highly suspect the tail-fin, but FAR's wing leveling assistant got terribly confused. If I passed a certain roll angle (maybe 45 degrees) the plane would try to snap to 90 degrees but momentum would carry it thrugh and the plane would want to fly upside down. This generally ended poorly.

That said, the plane cruised beautifully at 290m/[email protected], and fairly well getting into orbit and not too badly reentering (hand trouble slowing, thus a long cruise back to KSC). Of course, I didn't land well , but that's my fault (no flaps or spoiler, came down too fast, my "joystick" leaves a lot to be desired, and my skills more so)

[StevenJ]

ferram4: While I approve of the move, I suspect you'll get a flood of complaints about FAR breaking the CoL indicator :/

On a separate note: I used a rather tall tail-fin on my delta-wing plane last night and had some issues with roll/yaw stability. I take it having a tail-fin nearly as tall as your delta-wing is wide (from the center of the craft, not tip-to-tip) will lead to problems due to the torque from the yaw inducing roll.

Also, I'm not sure what it was though I highly suspect the tail-fin, but FAR's wing leveling assistant got terribly confused. If I passed a certain roll angle (maybe 45 degrees) the plane would try to snap to 90 degrees but momentum would carry it thrugh and the plane would want to fly upside down. This generally ended poorly.

That said, the plane cruised beautifully at 290m/[email protected], and fairly well getting into orbit and not too badly reentering (hand trouble slowing, thus a long cruise back to KSC). Of course, I didn't land well , but that's my fault (no flaps or spoiler, came down too fast, my "joystick" leaves a lot to be desired, and my skills more so)

We all start from somewhere. I thought I'd share some of my designs. They are mix of procedural wings, firespitter, b9, kerbenov, TAC life support, Deadly Re-entry, and space plane plus. These few images should do.

My heavy lifting S2 bodied shuttle Silversword

http://cloud-4.steampowered.com/ugc/563266737867834348/9A8974B6B0F63C52D563F3E73C375FB3D77F3F83/

http://cloud-2.steampowered.com/ugc/563266737867832516/A25A027DA22901B4AB084E04AC33051A0A33B2BB/

My flying Cesna clone

http://cloud-4.steampowered.com/ugc/571147403594847424/40E6A2C7E181C717EE2983E3372787152234DCAC/

http://cloud-4.steampowered.com/ugc/571147403594846610/14BC33AA9AE4DE657403852B7286C85AF57D8CB7/

My Silvershadow MKII prototype, I did some more work to it since then and added a third tailfin in the middle. This fighter plane is partaker in the Kerbal Royal Airforce ASF (Advanced Star Fighter) program. (No in flight photos )

http://cloud-4.steampowered.com/ugc/563266737867831863/71269318333015E33B882A05E1E0600E1D6C7C6A/

http://cloud-4.steampowered.com/ugc/563266737867830616/3E4D5AB642CA8B2A4FD16758993561D782329AC7/

http://cloud-4.steampowered.com/ugc/563266737867831252/366799124F7AEE8A079838025EC87ACE5428E53E/

And my ultimate goof off craft! My E200 Stunt plane!

http://cloud-4.steampowered.com/ugc/571147403594849048/FC7DA67168709CB2D80BC73540D5E51BA31414BC/

http://cloud-4.steampowered.com/ugc/571147403594851784/8C9577B54266F7D0FB8146EEF5213241C2C83083/

Jeb's an awesome stunt pilot in his spare time! Buzzing the tower is a national past time, I'll have to try and do a video some day of buzzing the tower in one my firespitter stunt planes

Anyway they all have separate elevators, flaps, ailerons, and air brakes. Now there is an exception, on my space planes on the sph4 control surfaces from procedural wings I use those as flaps and elevators. The reason for this is so I have dynamically adjusting flaps so If I find myself pitching down, I can pull up and the flaps, since they are set to elevators, automatically back off when I pull up then they return to their original position afterwards.

[Sevio]

@Sevio: That's probably something to do with the difference between the transform of the new vessel root part (the docking port) and the part you're controlling from (the cockpit). I'll look into finding a fix. I'll probably just have to run the control orientation code again, no big deal.

The exceptions are due to a bug that I've already fixed for the dev build; that should be out whenever I fix this one.

@ferram4: Thanks for looking into it, if it would help I can try producing a test assembly to try to reproduce the problem on the runway.

[Sevio]

Ok it's actually fairly simple to reproduce: Start in the SPH with an orange tank, attach a docking port to the back, then build from that docking port a simple plane with canards / elevons and a tailplane, the cockpit should be facing away from the hangar door as should the winglets. Launch, decouple the docking port and you'll get inverted control surfaces.

[steve_v]

Vertical stabilisers with comparable lift / area to the main wing will cause serious problems with roll stability - at least with real planes (or so I have read ;-)

@ferram4: Please do remove the COL vector indicator, I for one have been ignoring it for some time.

[Jasmir]

Hi Ferram,

i think i found a issue:

-> there seems to be lots of aerodynamic stress in space

KSP is 0.24.2, running on Win7/64 as 32Bit Version

Mods:

DeadlyReentryCont_v5.2
DebRefund-1.0.12DebRefund-1.0.12
DockingPortAlignment_4.0
EditorExtensions_v1.3
Ferram_Aerospace_Research-v0.14.1.1
Fine_Print-0.53a
Firespitter_634
GoodspeedPump-2.14.1
HotRockets_7.24_Nazari
KerbalAlarmClock_2.7.8.2
Kerbal_Joint_Reinforcement-v2.4.3
KW_Rocketry-2.6c
Magic_Smoke_Industries_Infernal_Robotics-0.18.3
MechJeb2 Build #281
MechJebFARExt.zip from 02.08.2014
ModularFuelTanks_v5.1.1
ModuleManager.2.2.0
ProceduralParts-0.9.17
RealChute v1.2.3
ResearchThemAll
SelectRoot-Jul18
StationScience-1.1
TacFuelBalancer_2.3.0.2
TacLifeSupport_0.9.0.9-pre3
Taurus_HCV_-_3.75_m_Stock-ish_Crew_Pod-1.2.1.1
Toolbar-1.7.6
VertVel113

Output.log/saves: tmp.7z

[ferram4]

Well, you're going to have to tell me exactly what you did to cause that first. Are you certain that at 00:16:57 that you were at an atmospheric pressure of 0?

[Jasmir]

I did a normal dorbit burn, and make a quicksafe (in space). After the reentry, i overdo it a little in the deeper atmosphere and some winglets go off.

I make a quickreload, and _all_ winglets go off every time direct after the reload (in space).

At 00:16:57 i was in space, so the atmospheric pressure should be 0. (It seems to be the exact moment of the quickload)

Edited August 3, 2014 by Jasmir

[ferram4]

I have attempted these steps and cannot reproduce the behavior you describe; in each case, all of the winglets are stripped from the vehicle during the initial reentry, and then the quickload results in a spacecraft in space, but all winglets remain attached. There are other steps missing, the issue is not present with a correct installation of FAR, or another mod is interfering somehow to cause the issue.

[Jasmir]

I'am trying to narrow it down. I hava a feeling about these KSPAPIExtensions-Mods...

[SilentWindOfDoom]

I enjoy the mod, though for me personally the aerodynamic stress model is too punishing, with the way I fly (keyboard) tapping the keys while flying at high speed just to make sure i don't break my wings off is the opposite of fun.

I was looking at the .cgf files to see if i could adjust something to tone it down a bit, but I am afraid I cannot make heads or tails of it, can someone inform me what i should tweak?

[tetryds]

I enjoy the mod, though for me personally the aerodynamic stress model is too punishing, with the way I fly (keyboard) tapping the keys while flying at high speed just to make sure i don't break my wings off is the opposite of fun.

It's because you are doing it wrong.

I personally find the aerodynamic stress model quite easy to deal with, here are some tips:

-For keyboard control, don't tap, tapping can cause oscilations, and a dynamic pressure peak will destroy your aircraft.

-Instead, hold ALT and pilot via trim at very high speeds, it takes practice, but works (remember ALT+X to zero the trim).

-Decrease the ammount of control from your control surfaces, at supersonic speeds, after proper trimming, you don't need much to pilot.

-Limit your engine, I know it's hard, and it feels like you are not supposed to do this, but do it.

There are many more tips but I don't want to make it too long.

Edited August 3, 2014 by tetryds

[Bekiekutmoar]

Is it true that FAR doesn't like other mods beiing partially incompatible with KSP (in my case the Firespitter part of Spaceplane Plus) ... ? That might explain why my planes don't break up in mid-air anymore when turning 90 degrees at high velocity, the 'simulation' in the SPH says Cd will be 15 at any velocity, and the FAR-button doesn't work while in mid-flight ... !

[taniwha]

Bekiekutmoar: I doubt it. I had no such trouble with my plane last night. It even broke up quite spectacularly at times.

[SilentWindOfDoom]

It's because you are doing it wrong.

I personally find the aerodynamic stress model quite easy to deal with, here are some tips:

-For keyboard control, don't tap, tapping can cause oscilations, and a dynamic pressure peak will destroy your aircraft.

-Instead, hold ALT and pilot via trim at very high speeds, it takes practice, but works (remember ALT+X to zero the trim).

-Decrease the ammount of control from your control surfaces, at supersonic speeds, after proper trimming, you don't need much to pilot.

-Limit your engine, I know it's hard, and it feels like you are not supposed to do this, but do it.

There are many more tips but I don't want to make it too long.

I appreciate the effort you took to reply, but I am only interested in nerfing the effect of the aerodynamic stresses, not in learning how to design and pilot all over again. It's a cool mechanic, but for me it has been taken a bit too far to be any fun. Back when i played IL-2 Sturmovic, a flight sim that thoroughly kicked my ass I didn't have to walk on eggshells the way I have to do in FAR now as it stands.

So I hope someone can point me at the relevant numbers and which way I have to adjust them, else i'll muck around some more on my own.

[Master Tao]

SilentWindOfDoom,

Your username is hilariously appropriate for your problem.

Also, check out this post, or just turn on DCA in flight and adjust your control surface deflections in the SPH.

[Bekiekutmoar]

Bekiekutmoar: I doubt it. I had no such trouble with my plane last night. It even broke up quite spectacularly at times.

Well, looks like FAR has 'awaken' again in my game; ingame GUI is working again and plane-parts all over the place when turning too sharp ... !

[SilentWindOfDoom]

SilentWindOfDoom,

Your username is hilariously appropriate for your problem.

Also, check out this post, or just turn on DCA in flight and adjust your control surface deflections in the SPH.

Much obliged! Thank you.

[Bekiekutmoar]

Hmmm, got some weird issues again although its very much possible its between my ears. This plane flies ... too well ... ! It's a passenger plane but its very agile and just refuses to break up in mid-air, no matter how extreme I turn it. Second, the diagram that 'simulates' the fly-ability of a plane shows a very high Cd (19 ... !!). And while flying the plane, the 'FAR-button' doesn't work.

I suppose an output log would even provide better information ... ?