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

[nuclearping]

After a while playing my UI suddenly starts to flicker like crazy. When I press Alt+F2 to open the Debug Log I see lots of red messages saying

[Exception]: ArgumentException: Value does not fall within the expected range.

When I look in my KSP output_log.txt it also has alot of lines saying:

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 

This goes on until the GUI eventually totally vanishes or until I QuickSave and reload the game. But after reload the problem reappears after several minutes. I'm already using latest FAR version 0.14.1.1.

Edited September 1, 2014 by nuclearping

[ferram4]

Known issue, fixed in the dev build in the github repo source.

[nuclearping]

Ok great. Is there already a build available you can link me?

[ferram4]

It's in the source repo. Linked from the OP. That's why I mentioned the github source.

[nuclearping]

Ok, I will grab it there. Thanks.

[nli2work]

hi ferram, what's the proper pivot alignment for obj_ctrlSrf transform for FARControllableSurface? like stock SPH Y-forward; Z-down; X-right? or something different? I'm making some pWings using your module, the control forces are correct, but the movement is rotated somehow... If I press Q/E to roll; the surfaces move like I'm pressing W/D. and vice versa. experimented at 90 degree increments. but no orientation seem to change the visible behaviour. changing ctrlaxis to yaw or pitch doesn't seem to make a difference either.

[ferram4]

You don't need to set that if you're using the same setup as stock; that's only there if you want to change it to something else for some reason. Don't know why I added it, but people like options, so if I remove it now someone will complain.

[nli2work]

I'm using the same setup as All move surface from pWings, if I remove obj_ctrlSrf; the whole thing doesn't move and I get constant NRE from get_MovableSection. I tried supplying a transform with movableSection = and MovableSection = neither worked as far as I can tell. I haven't been able to figure out a correct setup for the other types even after importing the pWing MUs to blender. The plane flies correctly, just that the surfaces move incorrectly.

[ferram4]

Yeah, it's hard-coded to look for obj_ctrlSrf, because AFAICT, the game is hard-coded to look for obj_ctrlSrf for the stock control surface code. Since all the parts that have control surface code have also included an obj_ctrlSrf transform to work with the stock module, this has never been an issue.

[nli2work]

your module working fine; I just can't figure out a way to get give it the right orientation.

this is as far as I've been able to get; as you can see the response should the other way around. Flight behaviour is correct, but visually it's switched. Maybe DYJ will shed some light if he resplies in the pWing thread. I've matched all the pivots orientations and transform names to his AllMove Wing piece from what I can tell (it's imported back to Blender, so I can't be sure it's correct), I simply don't know where else I should be looking.

Edited September 2, 2014 by nli2work

[ferram4]

All I can think of is that you're not setting up the FARControllableSurface module correctly for the part (though I'm not sure how you'd manage that) or the transform isn't lined up correctly somehow, but I'm not sure how that would cause this issue but not any others in deflection.

[Mister Spock]

So I'm curious what payload sizes are feasible with FAR (and Deadly Re-entry) installed. I searched in this thread and found one person who sends 80-ton payloads into orbit. I can hardly manage 20 tons! With FAR installed, I've been trying to build tall, thin rockets, but the VAB has a height limit. I guess I should be using more booster stages and such. How do you all lift heavy payloads into orbit with FAR?

[Wanderfound]

So I'm curious what payload sizes are feasible with FAR (and Deadly Re-entry) installed. I searched in this thread and found one person who sends 80-ton payloads into orbit. I can hardly manage 20 tons! With FAR installed, I've been trying to build tall, thin rockets, but the VAB has a height limit. I guess I should be using more booster stages and such. How do you all lift heavy payloads into orbit with FAR?

Considerably more easily than in stock; no soupmosphere drag to deal with.

If you don't care about cost, then a KR-2L driven core surrounded by a few layers of asparagus or onion staged LFBs will fairly easily lift as much tonnage as you could want for any sensible purpose, and manage it with a fairly low part-count, too. This sort of design is highly scalable; you can keep adding or removing layers until you have the TWR and ÃŽâ€V you want. Just don't forget the nosecones, keep an eye on your CoM/CoL relationship, and make sure to do a proper gravity turn rather than a stock-aero style "hard right at 10,000m".

You can do this much cheaper if you replace the LFBs with SRBs, but you'll need a lot of them.

If you do care about cost, a not-ridiculously-huge spaceplane can manage about a 50 ton payload while still being easy to fly. If you're willing to go bigger and wrestle with something a bit aerodynamically unruly, you can triple that without too much trouble.

For a demo of a heavy lift non-Whackjobbed SSTO spaceplane, see http://forum.kerbalspaceprogram.com/threads/90337-Economic-Fuel-to-Oribit?p=1361984&viewfull=1#post1361984

That one is a tanker, but a similar design with a few tanks replaced with cargo bays will work just as well.

For a heavy lift vertical SSTO, see http://forum.kerbalspaceprogram.com/threads/90747-Kerbodyne-SSTO-Division-Omnibus-Thread?p=1374206&viewfull=1#post1374206

I don't have an example of a rocket design ready to hand, but if you want I'll be happy to slap something together and send you the craft file so you can reverse-engineer it.

[Wanderfound]

Actually, I've just remembered that I do have a big rocket handy. See https://www.dropbox.com/s/xu7b5nt56qwfwst/Monstro.craft?dl=0 for the craft file. It should hit orbit just around the time you lose the last ring of boosters, leaving both the payload and the core still fuelled up.

[nli2work]

All I can think of is that you're not setting up the FARControllableSurface module correctly for the part (though I'm not sure how you'd manage that) or the transform isn't lined up correctly somehow, but I'm not sure how that would cause this issue but not any others in deflection.

Ok, finally sorted it out... something I didn't expect at all and seemingly unrelated. took out the mirrorRefAxis line; and all works and looks correct now. Just one of those voodoo things like airlock placement I guess.

[Piwikiwi]

I have a problem but I'm not sure if it is FAR related. I've build this aircraft and it rolls sharply to the left even though it is completely symmetrical.

Do you guys have any clue what might be causing this?

[DaMichel]

Ferram, could you please tell us something about the wing interactions which i have been reading about in the NEAR thread? Obviously you referred to multi-part wings, did you? But do wings that are spaced further apart also interact. For example, i read on wikipedia that canards can change the airflow over the main wing. Does FAR model this, too?

[steve_v]

So I'm curious what payload sizes are feasible with FAR (and Deadly Re-entry) installed.

I'm Lifting ~45T at a time with my current cargo spaceplane (B9 HL series parts), not very efficient but easy to fly, landing speed <80m/s - my landing skills suck. The heaviest *rocket* I recall was ~100T payload, but I used FSHangarExtender to build it - This was a space station spine, so it was tallish.

Edited September 2, 2014 by steve_v

[Mister Spock]

@Wanderfound: thanks for your reply, and especially for that .craft file. I'll check it out when I get home.

@Steve: Ah, so there's a mod that makes the VAB taller? I'll check that out, too. Thanks.

[Voculus]

Ferram, I just wanted to say after nearly 1300 hours in KSP, I finally installed your mod, and am blown away by the depth and detail you were able to pull off. I'm learning to fly spaceplanes all over again, and find the flight sim muscle memory coming to the fore, rather than just yanking and banking like a madman in stock. Awesome!

[ferram4]

@DaMichel: Besides increasing the lift and decreasing the drag of any wing part that is in the middle of a wing from its baseline performance (essentially, increasing the effective aspect ratio of that part), FAR also includes the effects of changes in lift and drag caused by changes in the camber of the wing, whether that is caused by the shape created by wing parts or by control surfaces deflecting. Further, the stall angle of wing parts is affected by multipart-wings as well. There's also the effect of biplane wings robbing each other of some lift due to interference effects.

NEAR models none of that.

The canard effects you're talking about would be the result of downwash behind the canard, and lack of downwash is one of the last remaining great errors in FAR; I just haven't come up with a good way to handle it yet, though the math for it is relatively simple.

@Voculus: Good to hear, it's always nice to know that FAR brings things closer to flight-sim quality.

[Nori]

When ascending with a rocket is it best to use stock SAS or a combo of the FAR flight assistants? I've had a few situations, which have served as a learning experience, where after hitting mach 1ish my rocket starts swinging back and forth very violently. It appears to me to be a combo of poor control surface placement and SAS overreacting. I ended up "fixing" it by putting the control surfaces closer to the center of the rocket (as opposed to on the drop tanks/SRBs attached radially) and also putting a high gimbal radial engine on each side of the rocket.

Is it best to have control surfaces on a rocket or just fins of some sort?

[RadarManFromTheMoon]

Hello ferram4,

I'm currently working on a mod that adds procedurally generated airship envelopes to KSP. FAR compatibility would be great so I started experimenting and came across something that seemed weird (at least to me).

I was essentially doing this:

Vector3 pos = part.rigidbody.worldCenterOfMass;

double alt = FlightGlobals.getAltitudeAtPos(pos);

Log.post("altitude of pos: " + alt);

Log.post("density at alt: " + ferram4.FARAeroUtil.GetCurrentDensity(FlightGlobals.currentMainBody, alt));

Log.post("density at pos: " + ferram4.FARAeroUtil.GetCurrentDensity(FlightGlobals.currentMainBody, pos));

Log.post("density ASL: " + ferram4.FARAeroUtil.GetCurrentDensity(FlightGlobals.currentMainBody, 0.0));

This was the output:

altitude of pos: 75.625

density at alt: 1.18777573990506

density at pos: 1.2723385536664

density ASL: 1.20361260315657

The first two values should be the same or am I just using it wrong? I tried it with version 0.14.1.1 and the newest dev build from the repository. It's the same with both.

[ferram4]

@Nori: It depends on the rocket. However, if your rocket is oscillating in certain situations, that either means too much control authority in general, not enough stiffness in the design, or SAS just being tremendously wrong for some reason.

@RadarManFromTheMoon: They should be identical, but the only place where it could return different values is in the overloads for FlightGlobals.getStaticPressure and FlightGlobals.getExternalTemperature, since the only difference between those functions is in the overloads they call... So this seems like either FlightGlobals.getAltitudeAtPos is returning the wrong number, or one of those other FlightGlobals functions is returning the wrong number.

In any case, this doesn't look like something I can fix, but thanks for the heads up; I'll look into replacing one of them to make it more consistent.

[RadarManFromTheMoon]

Thanks for the sudden reply.

I'm sorry I should have tested a little further because it's actually pretty simple. FlightGlobals.getAltitudeAtPos() returns the correct altitude, but FlightGlobals.getExternalTemperature(Vector3) however just returns 0.