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

[illectro]

@illectro: That is a bug in FAR v0.12.4 and earlier; update to v0.12.5.1 and it should be gone. I just hope you didn't update to v0.12.5; that one was quite nasty.

OK in that case it's a completely different bug, I'd been using 0.12.3 and upgraded yesterday, now after flying then attempting to start a new flight the game crashes. I get a pile of null ref exceptions, no stack traces or anything, I'm going to do some poking just to make sure that the change in FAR is relevant.

[ferram4]

Go into KSP_Data and post the output_log.txt in full. That should point out the error loud and clear.

I know what I've gotten a few bugs that can be traced back to RemoteTech 2, so that might be an issue... Hopefully, it's nothing too bad.

[lilzkiller]

I just tested a rocket and i guess it was another mod that was causing my rocket to pull horribly to one direction and the col indicator just happened to be going the same direction so I thought it was FAR.

[illectro]

Go into KSP_Data and post the output_log.txt in full. That should point out the error loud and clear.

I know what I've gotten a few bugs that can be traced back to RemoteTech 2, so that might be an issue... Hopefully, it's nothing too bad.

If this is helpful, feel free to offer your expert opinion. I would not be surprised if other mods are implicated.

http://www./view/lasnb68kkunazns/output_log.txt

[ferram4]

First, you've got a loading error for ExsurgentEngineering.dll, which B9 uses for its SABRE and some jet engines and it probably needs to be updated for KSP 0.23; a little searching brings up this link for a KSP 0.23-compatible ExsurgentEngineering.dll. It also requires the firespitter.dll from the Firespitter Pack, so just download the pack and only copy over the dll to make sure that it's KSP 0.23-compatible. B9 should work quite nicely after that.

There are a few exceptions in there caused by SafeCute; I don't know if that's because the mod hasn't been updated for KSP 0.23 or it's an old bug that didn't get squashed.

There are a bunch of other ones caused by "MBActionOTF" but I don't know what mod that is from.

And there's one odd one caused by RemoteTech 2, which I think is caused by docking, but I've only caused it intermittently, so I'm not sure what the actual circumstances are leading up to that.

[Dreadp1r4te]

Is this mod readily uninstallable? I'm curious to try it out as it's very highly recommended, but I have enough trouble designing working spaceplanes that if it makes things too much harder I might not enjoy it much.

[ferram4]

Just deleting the FerramAerospaceResearch folder in GameData is enough to uninstall it. The other included 000_Toolbar folder and ModuleManager1_5_5.dll can also be deleted if another mod you're using isn't dependent on them, but that's something you should check before getting rid of those.

Overall, it's surprisingly easy to uninstall a mod. It's just deleting a folder.

[Dreadp1r4te]

Just deleting the FerramAerospaceResearch folder in GameData is enough to uninstall it. The other included 000_Toolbar folder and ModuleManager1_5_5.dll can also be deleted if another mod you're using isn't dependent on them, but that's something you should check before getting rid of those.

Overall, it's surprisingly easy to uninstall a mod. It's just deleting a folder.

Oh no, I know it's very easy to uninstall a mod, but I knew this changed stock aerodynamics so I wasn't sure if it overwrote the files (the wings and such) or used MM to append them. Thanks for the quick answer though! I'll give it a shot and see what happens.

[Volt]

Does anyone in the dev team has proper knowledge of aerodynamics?

I couldn't say. I assumed that Chad did long ago, but only because he created the very first hit wing pack back in, oh, 0.12? 0.13? Maybe even before that. But actually, Harv is probably most knowledgeable in that field because he's the one that created the original lift/drag system, weird as it may be. But there's no way they match Ferram's in-depth insight, hence why this mod so realistically recreates aerodynamics.

[illectro]

There are a few exceptions in there caused by SafeCute; I don't know if that's because the mod hasn't been updated for KSP 0.23 or it's an old bug that didn't get squashed.

There are a bunch of other ones caused by "MBActionOTF" but I don't know what mod that is from.

And there's one odd one caused by RemoteTech 2, which I think is caused by docking, but I've only caused it intermittently, so I'm not sure what the actual circumstances are leading up to that.

Let me poke these things, and see whether it's still an issue, I'm glad for the pointers even if it's not your mod responsible. (On there other hand, the number of flat spins I'm getting into are almost certainly related to FAR updates).

[ferram4]

@Dreadp1r4te: I'm going to warn you: remember when you first started launching rockets and you had no idea what you were doing? Welcome back to being a newbie. Be aware of the challenges, and you'll learn. Just start with getting to orbit again, and work up from there.

@illectro: Well, that's bad design, partially caused by the increases in body lift that I made since you requested the ability to continue doing crazy lifting body things.

Edited January 7, 2014 by ferram4

[Dreadp1r4te]

@Dreadp1r4te: I'm going to warn you: remember when you first started launching rockets and you had no idea what you were doing? Welcome back to being a newbie. Be aware of the challenges, and you'll learn. Just start with getting to orbit again, and work up from there.

Well, considering I've always launched aerodynamically sound rockets and used a true gravity turn to get into orbit, I might not crash TOO often. XD Well, there was that one time I put a 150 ton circular space station into orbit in one mission...... but that was more for kicks. That reminds me, I need to de-orbit that station...

[toadicus]

There are a bunch of other ones caused by "MBActionOTF" but I don't know what mod that is from.

MBActionOTF is from Actions on the fly, which according to its thread and spaceport hasn't been updated in a good long while. My guess is illectro's got a version with some changes to the code listed deep in the "mods broken by 0.20" thread, and the Exceptions are throwing because FlightGlobals.ActiveVessel is null when it is called (very early; maybe even before Awake). However, the mod will probably still work because in a later Update call, FlightGlobals.ActiveVessel != activeVessel is true, so it re-runs the initialization. So those messages are probably harmless-ish, maybe?

[taniwha]

The mod might work, but the exception could break other things. I've seen exceptions in my non-physics related code cause severe physics breakdowns. Heck, I've had exceptions in my code cause 90% of GamaData to not be loaded .

[illectro]

You know, it might be simply that the last 6 hours or so of play after I upgraded to 0.23 were almost exclusively in space so no aerodynamics were invoked and the particular problem wasn't tickled.

As for the lifting body changes being responsible for my recent brush with death - It flew well under 0.10 but upgrading to 0.11 made it spin out, I thought that 0.10 -> 0.11 reduced the lifting body effect.

Regardless, it's all fun nevertheless.

[camlost]

I couldn't say. I assumed that Chad did long ago, but only because he created the very first hit wing pack back in, oh, 0.12? 0.13? Maybe even before that. But actually, Harv is probably most knowledgeable in that field because he's the one that created the original lift/drag system, weird as it may be. But there's no way they match Ferram's in-depth insight, hence why this mod so realistically recreates aerodynamics.

That's not aerodynamics, that's like two made-up equations with some eye-balled parameters. It's been there for over a year and nothing has been improved. Mine was a rhetorical question.

[ferram4]

@illectro: I look forward to the Duna mission trying to get into orbit there. The aerobraking/aerobreaking should be interesting. Have you considered how you're going to keep that... thing stable in Duna's atmosphere? Because I'd try spinning it up around its major axis (the one that gives it the largest moment of inertia possible) so that it doesn't end up tumbling during the aerobrake.

[illectro]

I'm planning to split the vehicle into 2 autonomous sections, the odds are the aerodynamics will overstress the whole ship so just deal with it in advance.

Anyway, With RT2 removed things appear to be working just fine for now, well at least I managed one flight without a crash, we'll see how it stands up to repeated abuse.

[ferram4]

Make sure the two ships have similar densities or they're going to end up in completely different orbits.

Actually, if you spin up the ship properly so that all the connections are in tension, and then make sure that the axis of rotation is in the same direction as the velocity it'll probably hold together; if everything is sideways to the flow everything will have about the same drag coefficient and there won't be huge differences in aerodynamic forces across the vehicle. By spinning it up so everything is in tension you'll cause centrifugal forces to act as a sort of restoring force to counter any aerodynamic forces that might cause it to flex out of control.

[Dreadp1r4te]

How did I ever fly spaceplanes before this. Oh my GOD. Ferram, you sir, are a GENIUS. Absolutely brilliant. My first flight out of the hangar in a craft I had recently designed, and was having trouble with because pWings don't seem to want to accurately indicate the CoL (which apparently installing this fixed) I lifted off the runway with all the grace of a figure skater, I swear. Not only that, but using KSPI's nuclear reactors and thermal hybrid turbojets (think SABRE engine, but powered by a nuclear reactor, and doesn't require fuel when in atmosphere, although I'm pretty sure the two 14 ton nuclear reactors count as fuel) I got this 100 ton spaceplane into orbit using only half of its fuel supply, which prior to FAR required about 80% of its fuel. Ferram, you have my heartfelt thanks. You do indeed make things fly.

[a.g.]

The mod might work, but the exception could break other things. I've seen exceptions in my non-physics related code cause severe physics breakdowns. Heck, I've had exceptions in my code cause 90% of GamaData to not be loaded .

The RemoteTech exception looks the most dangerous, because it happens when the stock Vessel.OnDestroy function calls registered events. This means that any event handlers after the current one and the remainder of the OnDestroy method won't get executed.

[Black-Talon]

@illectro: I look forward to the Duna mission trying to get into orbit there. The aerobraking/aerobreaking should be interesting. Have you considered how you're going to keep that... thing stable in Duna's atmosphere? Because I'd try spinning it up around its major axis (the one that gives it the largest moment of inertia possible) so that it doesn't end up tumbling during the aerobrake.

Sorry for the off-topic comment, but I'm similarly anticipating this. I love seeing the mods exciting people to create, and the creations driving new ideas in the mods. My giddy-engineer gets a triple dose as I create my world in KSP, debug and dream mods, and read and watch the rest of you. Thanks for the excitement!

[Dreadp1r4te]

Okay, so after further toying around with this I've come across some issues on re-entry and I'm not sure what's causing them. Here's the craft in question:

Whenever I try to re-enter the atmosphere from LKO (around 100km) I end up, invariably, in a perfect 0 degree flatspin, and can't recover from it no matter what I try. I've tried numerous angles of approach, from entering the atmosphere nose first, as the craft would fly, and when that didn't work I tried a 15 degree angle, 45 degree angle, and a 90 degree angle. Everything results in the craft tumbling out of control, then just when it seems like I might regain it, it shifts into a flat spin with the nose on the horizon and falls straight down. What am I doing wrong here? Atmospherically this craft flies like a dream, cruising right up to LKO at a 25 degree climb. I'm no aerospace engineer, so any help here would be appreciated.

(I know the radiators are producing extra drag, but they're necessary so the KSPI reactors don't overheat, and since the craft flies fine from the runway to orbit, I don't think they're the issue)

[ferram4]

There are a few possibilities I can think of. The first is that when you empty the cargo bay of whatever's in there and go to land it you end up with the CoM moving back enough that it becomes unstable. That would be the case if it starts to pitch up out-of-control as you hit the atmosphere. The solution is to mess with your wing design to put the CoL further back, and make sure to add more pitch control surfaces to compensate for the added stability, which will make flying it a little bit more difficult. If that doesn't work, you might have to redesign the craft so that the CoM doesn't move appreciably after te payload is deployed. Odds are you can just shrink the wing a little bit and shift it back and it'll be fine, make it look more like the wings on the Space Shuttle, which are further back.

The second is that you don't have enough yaw stability; if that's the case it'll start to roll out-of-control before tumbling. Basically, the lift of a wing is partly dependent on its angle of sweep; more-swept wings make less lift than less-swept wings. If the plane starts to sideslip, say 5 degrees to the left, then the left wing is swept 10 degrees more than the right wing, causing the plane to roll to the right. The solution is a bigger vertical stabilizer, using RCS to artificially create yaw stability during decent, or building a small angle of attack into the vertical stabilizers so that they are more responsive to sideslip, similar to the way the X-15 has a giant, fat wedge as a vertical tail, though that will lead to a lot more drag on the vehicle.

And if you can get away with it, I'd say to try stowing the radiators in the cargo bay if you can, since that'll prevent them from affecting the aerodynamics of the vehicle.

[Dreadp1r4te]

There are a few possibilities I can think of. The first is that when you empty the cargo bay of whatever's in there and go to land it you end up with the CoM moving back enough that it becomes unstable. That would be the case if it starts to pitch up out-of-control as you hit the atmosphere. The solution is to mess with your wing design to put the CoL further back, and make sure to add more pitch control surfaces to compensate for the added stability, which will make flying it a little bit more difficult. If that doesn't work, you might have to redesign the craft so that the CoM doesn't move appreciably after te payload is deployed. Odds are you can just shrink the wing a little bit and shift it back and it'll be fine, make it look more like the wings on the Space Shuttle, which are further back.

The second is that you don't have enough yaw stability; if that's the case it'll start to roll out-of-control before tumbling. Basically, the lift of a wing is partly dependent on its angle of sweep; more-swept wings make less lift than less-swept wings. If the plane starts to sideslip, say 5 degrees to the left, then the left wing is swept 10 degrees more than the right wing, causing the plane to roll to the right. The solution is a bigger vertical stabilizer, using RCS to artificially create yaw stability during decent, or building a small angle of attack into the vertical stabilizers so that they are more responsive to sideslip, similar to the way the X-15 has a giant, fat wedge as a vertical tail, though that will lead to a lot more drag on the vehicle.

And if you can get away with it, I'd say to try stowing the radiators in the cargo bay if you can, since that'll prevent them from affecting the aerodynamics of the vehicle.

This is with an empty cargo bay at all points in the flight; it's CoM is tailored so that draining the fuel from the tank (which is directly afore of the reactors/engines, behind the cargo bay) doesn't move it's CoM much, still keeping it ahead of the CoL. I designed it for retrieving payloads from orbit like decommissioning stations without just de-orbiting them; as such it's set up so that the weight in fuel it burns getting into orbit/rendezvousing with the target is replaced with the weight of whatever it's recovering in the bay, but as a fail safe it's set up so it can still land with no cargo/fuel load remaining. Since neither of those have been the case as these are just sub-orbital hops to test stability, I can kinda rule that out for now but I'll set it aside for future consideration. I have had trouble with pWings correctly displaying CoL, and I'm not sure if that has been corrected by or exacerbated by FAR, so it merits further testing.

I haven't put RCS on it yet, I'll try that first to see if I can stabilize it, in addition to increasing the size of the vertical stabilizers to increase yaw stability as I think that may be the culprit. Will post back with results.

EDIT:

I added a 3rd vertical stabilizer in between the initial two with its own rudder, as well as enlarging the other two rudders, added two reaction wheels, and a reasonably balanced RCS network that favors yaw control at the nose and is balanced otherwise around the CoM. I also temporarily stowed the radiators in the cargo hold to reduce drag. This had the net result of giving me outstanding roll authority, as well as the yaw authority needed to overcome the side slip that seems to be common on re-entry. She now lands as gracefully as she lifts off. Thanks a ton for the help Ferram!

Edited January 7, 2014 by Dreadp1r4te