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

[Nori]

@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.

Thanks for the response. Most likely I had too many control surfaces. Should there be one for each side? As in 4 total? I never know how many to put on, or if I should just put non-control surfaces on and rely on reaction wheels and gimbals instead.

[Wanderfound]

Thanks for the response. Most likely I had too many control surfaces. Should there be one for each side? As in 4 total? I never know how many to put on, or if I should just put non-control surfaces on and rely on reaction wheels and gimbals instead.

How long is a piece of string?

It depends on the rocket. Small rockets want few control surfaces, large rockets want many control surfaces (or a few very big ones). Generally speaking.

Y'just gotta experiment a bit. Go to the sandbox, control all but this variable, test and see what happens. Scientific method for the win.

[TheGatesofLogic]

anyone know if tweakscale plays nice with FAR?

[DaMichel]

Thanks for the detailed answer. I mostly wanted to know about the down wash issue. So basically FAR recognizes wings parts that touch each other as whole wing (more or less), but "long range interactions" are out? So for instance deeps stalls aren't either modeled.

Btw. I've been flying some rounds in DCS with the Su-25 and the TF-51 (P-51 variant) from time to time and i find the general behavior very similar to flying with FAR. Well with the TF-51 you have to take propeller torque into account which makes takeoff hellishly difficult. In fact my landing have become much better in DCS due to playing KSP I like helicopters more so i've only tried the freebie fixed wings.

Edited September 3, 2014 by DaMichel

[NathanKell]

While I plan to add torque and gyroscopic effects to my prop fork of AJE, I can at least tell you that with a properly constructed Mustang (H in my case) and its prop I'm getting 100% accurate speeds with FAR (probably because I tweaked the prop against FAR's drag of the parts ). So if you want to fly the Stang, now you can.

[Wanderfound]

It appears that planes with FAR-enabled control surface tuning won't load without FAR or NEAR installed. Due to this, I've been having to make two versions of my designs; one with tuned surfaces for the FAR/NEAR flyers, one without for the stock purists.

This is a bit of a nuisance. Is it possible to set things up so that altered maxauthority/flap/spoiler settings are just ignored when loaded into stock air?

[DaMichel]

@Nathan: Madness! (in a good way). I have to try AJE at some point. But say, is it possible to make space planes with it, at least for stock sized Kerbin?

[taniwha]

DaMichel: I haven't succeeded yet, but I'm using stock part masses and fuels. Also, I haven't tried much yet, either (just took a successful TVp&a design and tried it: couldn't get above Mach 2).

[RadarManFromTheMoon]

Hello, its me again with another question.

What is the best way to get the current static air pressure from FAR? FARAeroUtil does not seem to have a method for that, but GetCurrentDensity() takes the stock value and just applies an offset to it (besides converting it to pa, but I don't need that). Will I get sensible results by just resembling that behaviour, or am I overlooking something important here?

[NathanKell]

DaMichel: With a J58 you'll be switching at circa Mach 4 (~1200m/s) and ~18km (? --- I don't know what altitude on Kerbin corresponds with 25km on Earth) so you only need another km/sec or so from rockets. Seems reasonable to me.

RadarManFromTheMoon: FAR doesn't change air pressure, so you can use the stock methods.

[madlemur]

But, but, but... When will we get realistic control problems when going trans-sonic?

The movie depicts the "solution" to maintaining control at supersonic speeds as reversing the controls...

[Jaevko]

I love this mod. Thank you Ferram!!

I am having a few problems with aerodynamic failures. They are entirely my fault and I don't want to turn the setting off, I want to get better at building/flying. Any good guides? (Google hasn't revealed much, so sorry if I missed something in my searches)

Take this lander for example. To have it survive launch (high dynamic pressure/aerodynamic failure) do I simply need to accelerate really slowly through the lower atmosphere? Or is there another trick? (One of those fairings mods? Are there any fairings big enough to hold MASSIVE landers or space station modules?)

As for reentry, I'm slowly figuring it out for spaceplanes (just slowly dissipate speed in the upper atmo and don't dip too low until you are slow enough...still can be tricky though and tips would be appreciated). What about landers like the one above? Can they be used for in-atmo planets like Eve or should I relegate them to vacuum landings only? (In other words, am I pretty much limited to beautiful sleek B9 splaceplanes for in-atmo places like Eve, Kerbin, Duna, or Laythe?)

[madlemur]

Procedural fairings might wrap up your behemoths... Or use InfernalRobotics/KAS to unfold/assemble/wrangle your sprawling beasties in space.

The snark/engineer/OCD in me wants to discuss basic design philosophy, but I'm trying to be better about not mouthing off about having fun the "wrong" way.

[ferram4]

@Wanderfound: I assume you mean that the settings for control surfaces won't load, rather than that the crafts won't load.

There's no way around that. FAR and the stock aerodynamics use completely different part modules, and there's no easy way to bring the settings from one module over to the other, particularly from FAR -> stock, because in stock, the FAR module doesn't even exist, so there's no way to load the data short of a manual parsing of the craft file to try and find the data, which will be a nightmare to try and code up.

@madlemur: Well, considering the thin wings that FAR assumes, the control problems aren't that bad. It's just that the ability to produce lift falls off a cliff.

@Jaevko: Those rocket tanks sticking off sideways? They're always going to get ripped off in any amount of high dynamic pressure. You're either going to have to set them up on IR hinges so that they can only deploy once dynamic pressure is lower or you'll have to come up with a sturdier way of putting the legs further out.

Landers for Eve will basically need to look like the kind of rockets that you'd launch from Kerbin, sort of the same with Laythe (though its smaller size means you can have lower dV requirements), but for Duna a plain old Mun lander with a little extra dV is enough. The trick in designing atmospheric landers is to look at them and think about where it will break if you apply a force across the entire thing.

[starkline]

Hello KSP forum. Since this is my 1st post, please be kind if I've misjudged my question's legitimacy.

I've been using the 14.1.2 dev build form github after reading FAR was causing a weird GUI flickering issue that popped up for me. Sure enough, the dev build seems to have elimited that issue. However, I have found a strange issue with the dev build that's not found in 14.1.1.

Let me try to explain this clearly. Using SpacePlane+ elevons I've found that I can add control surfaces, but I cannot set them to action groups. Furthermore, if I add more than 1 pair of the same type of control surface and then r-click on the 2nd added pair, it dissappears from view, but it still registers in the vessel part count. If only one pair of control surfaces are added, I can edit their paramter via r-click normally. Reverting to 14.1.1 eliminates the problem.

Normally, I use tons of mods, but I had only SpacePlane+, Toolbar, Ferram, and TweakScale installed. I did remove TweakScale during testing in order to reduce potential conflicts, but it made no difference.

I realize that a dev build is just that...not reliable for release, so if this post is just noise for ferram4, apologies and kind regards for making KSP aerodynamic. If anything, maybe the next release won't see this issue.

Cheers

[Virindi]

I am trying and failing to get a part to not exhibit any aerodynamic effects. I added part of the name under part classification, "Title Contains" section. I restarted KSP afterwards. I'm assuming this is the displayed title, not the part name, and that it is not case sensitive? Either way it doesn't seem to be working as expected (the part internal name also contains the string); I'm sure I'm doing something wrong but I can't figure out what.

I'd really like it to have zero drag (this 'part' is a flag decal, it just symbolizes a logo painted on to a vessel, so it should have no impact whatsoever). However, I can't add it to 'exempt' because the only module it has, is used on things which shouldn't be 'exempt'. That is, without editing the parts to add some other module (I suppose this could be done if needed).

What am I doing wrong?

Edit: after these screenshots I also tried setting part mass to 0. Same result.

Edited September 3, 2014 by Virindi

[Jaevko]

The snark/engineer/OCD in me wants to discuss basic design philosophy, but I'm trying to be better about not mouthing off about having fun the "wrong" way.

Please do, I'm open to criticism! My justification (as I said, I'm open to change): After way too many toppling incidents, I learned to build my landers low and wide. When I have to have all those science things on there making it tall, and need to have tons of fuel, the logical thing to do seems to be to use the fuel tanks as a way to broaden the lander and make the CG lower. Haha it worked very well in stock

@ Ferram Thanks, that helps a lot!

[NathanKell]

Virindi: There's two ways to go about disabling drag on a part:

1. Make FAR ignore it, *and* set its stock drag to 0.

2. Add a custom FAR module to its cfg with surface area nearly 0, which will leave it subject to FAR but make it not really create any drag.

[DaMichel]

... about a control surface bug ...

Yeah i noticed the same thing. I bet you get NullReferenceExceptions, too? Ferram4, please take a look at FARControllableSurface, about line 217, where you access vessel.ReferenceTransfrom. Obviously vessel can be null at at that point. I made a "fix" for myself but i don't know what i'm doing so i shut up now .

@Nathan: Thanks, that makes sense. Mach 4 is pretty fast for a jet engine though

@Jaevko: You can probably launch this without fairing or anything. But you have to fly really slowly, basically like hovering on the rocket thrust. No more than 10 kPa dynamic pressure. It is inefficient but it should work.

As atmospheric lander this would probably not work unless you want to spent enormous amounts of fuel on a powered descent. But you can build onion style layers of vertically aligned tanks. This works and is able to stand very high dynamic pressures. See the Eve lander in my sig.

Edited September 3, 2014 by DaMichel

[Virindi]

Virindi: There's two ways to go about disabling drag on a part:

1. Make FAR ignore it, *and* set its stock drag to 0.

2. Add a custom FAR module to its cfg with surface area nearly 0, which will leave it subject to FAR but make it not really create any drag.

#1 is not working for me. I set the following:

mass = 0
dragModelType = Default
maximum_drag = 0
minimum_drag = 0
angularDrag = 0
dragCoeff = 0
crashTolerance = 8
maxTemp = 1000
fuelCrossFeed = False
breakingForce = 200
breakingTorque = 200

What would the FAR-specific module be for zero drag?

EDIT: Nevermind, I got it...copied one of the ones in the config. Thanks for the help!

Edited September 4, 2014 by Virindi

[Jaevko]

@DaMichel: Thanks!

[Rib]

Hiya guys,

Made an account just to ask this.

Is there any way with Ferram Aerospace to find out the Specific Range of the Aircraft? Due to the new way in which the engines work, the efficiency of craft is currently being judged by rule of thumb.

If this isn't already a feature, then it would be an awesome feature in the future.

Just another quick question - does the installation of Ferram remove background simulation of the game i.e. when you tab out, I can't seem to get it to work.

I have just started using Ferram and to the guy who made it - you are a God among men. It is awesome. I thank you kindly.

[NathanKell]

Just another quick question - does the installation of Ferram remove background simulation of the game i.e. when you tab out, I can't seem to get it to work.

This was removed from the game itself. Not sure why you think FAR is to blame...

[Wanderfound]

@Wanderfound: I assume you mean that the settings for control surfaces won't load, rather than that the crafts won't load.

There's no way around that. FAR and the stock aerodynamics use completely different part modules, and there's no easy way to bring the settings from one module over to the other, particularly from FAR -> stock, because in stock, the FAR module doesn't even exist, so there's no way to load the data short of a manual parsing of the craft file to try and find the data, which will be a nightmare to try and code up.

Actually, I had folks tell me that the craft wouldn't load at all. Once I gave them a version with control surface tweakables reset to default, the issue went away. See the comments on http://forum.kerbalspaceprogram.com/threads/88628-Kerbodyne-D7-Heavy-X5-a-heavy-lift-SSTO-spaceplane for an example.

Something strange going on?

I'm wishing I could drop that plane down the memory hole, BTW. I was hugely proud of it when I first built it, but now it's an embarrassment.

-

While I'm bothering you with daft questions (thanks as always; you have the patience of a saint), is there any known issue with interaction between FAR and Hot Rockets?

I've got a vertical-lift SSTO (http://forum.kerbalspaceprogram.com/...=1#post1374206) that I designed a few weeks ago. At the time I designed it, I had both Hot Rockets and FAR installed. It launched just fine on air-breathers alone.

Then I got sick of long-running constant crashes (nothing to do with FAR), so I completely scrubbed KSP from my computer and reinstalled from scratch. Initially, I had FAR reinstalled, but not Hot Rockets. When I tried to take the SSTO for a spin, I found that it was no longer able to get off the ground without turning the oxidiser on.

But when I reinstalled Hot Rockets, the SSTO went back to easy air-breathing liftoffs like it had been before.

Is there some known interaction between Hot Rockets and FAR? My first suspicion was that HR was somehow reversing the the FAR engine nerf, but the kN thrust values look the same with or without HR.

Any clues? Is it at all plausible for HR to be doing this? And if so, which version of the spacecraft is the "correct" one?

Edited September 5, 2014 by Wanderfound

[ferram4]

@Rib: I'm looking into adding an estimated range readout to the Flight Data GUI, but it will end up severely underestimating the range of the plane because Kerbin's orbital velocities are so low that the effective reduction in gravity due to flying so fast will have a significant impact on range.

@Wanderfound: Yeah, there's no reason FAR should prevent that from loading. I suspect another issue on the user's end.

As for that odd interaction, that makes no sense: if both engines are producing the same amount of thrust in airbreathing mode than they will be applying the same amount of thrust. The only way this could be interacting is if there is some odd stock bug that you've run into. Also, your link is shortened and so it goes nowhere.