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

[Carlonord]

I noticed an issue with one of the part's calculations I think. After I reinstalled FAR in the newest version, the Comms DTS-M1 communicator started giving me phantom rotation in space and extreme drag in atmosphere. You may want to have a look at that.

[ferram4]

The dishes tend to be quite un-aerodynamic, though they shouldn't make much drag if they aren't deployed in the atmosphere.

Any phantom forces in space caused by dishes is probably a result of part clipping. When outside of the atmosphere FAR doesn't even run any drag calculations, let alone call the methods to apply them to parts.

[Carlonord]

Just bringing that up is all. I could even control the rotation which was interesting. It would rotate in one direction when not deployed, and the other when deployed. As for the atmosphere, I didn't have the dish opened. But somehow the drag from it was enough to cause my parachuting probe to list by about 5-10 degrees.

[GentlemanJack]

The CoM doesn't move at all after you burn fuel to get it in orbit? Use tweakables to remove fuel from the tanks that are empty on the craft in orbit (while you're in the SPH), and then tilt the spaceplane to the same AoA you were at when you lost control. If the CoL is still behind the CoM, then I'm going to guess that the problem is not enough yaw stability, which causes lots of rolling, and you're losing control that way.

The fuel should be fine i think, i'm using TAC Fuel Balancer to help with CoM change. I mean it seems like it's something to do with the control surfaces. They just lock up in mid descent and my craft is sent into an uncontrollable spin, FAR says it's a stall though.

I should say i'm also using Deadly Reentry

[Hyomoto]

@Hyomoto: Update isn't out yet, that's just a progress report. I still need to make sure that everything is functioning properly, so it might take until tomorrow.

Precision is clearly failing me. I read your post about an update you were currently testing, but I hadn't realized that the items in the right click menu were the coefficient readouts that you had stated were being removed. That is why I made my post asking if they were going to be removed. You had stated an update was in testing, so my original question should have done a better job showing it was a reply to yours, rather than an idle request.

I apologize for not using the quote button originally.

[taniwha]

GentlemanJack: TAC FB is not magic: it does not force the CoM to be anywhere . At best, all it does is make specified tanks have the same amount (not to say that TAC FB isn't useful, it very much is). You need to compare your CoM vs CoL with all tanks both full and empty: odds are the CoM is in different positions, and TAC FB can't do a thing about it.

[ghimb2000]

Is it a known issue that after install FAR, the lift rating of stock parts just don't show up anymore? I'll post pictures if needed, but it should be easy to test.

[KerbMav]

If I am right, than stock parts magically produced lift, but FAR actually calculates the lift by angle, vector, speed ...

[Dirt_Merchant]

Gentlemen, forgive me if this has been clarified in previous posts (and I do realize that nathankell had mentioned this in an earlier post) but have we a temporary fix for the tremendous drag generated by b9 & FS landing gear? I know that nathankell had mentioned "surfaceArea = 0.001" overriding far drag values, however, I am unclear as to where exactly to add this line. Thank you in advance for your help, time, or thoughts;)!

[GentlemanJack]

GentlemanJack: TAC FB is not magic: it does not force the CoM to be anywhere . At best, all it does is make specified tanks have the same amount (not to say that TAC FB isn't useful, it very much is). You need to compare your CoM vs CoL with all tanks both full and empty: odds are the CoM is in different positions, and TAC FB can't do a thing about it.

Ok so my CoM is a tiny amount behind the Col around the descent stage. My fuel is still about 20% full at the time i reenter and toggle my air breathing Sabre engine. Should i fix this by moving the wings slightly back to compensate for that?

Here are a couple of pictures of the plane. http://imgur.com/8L0a4CA http://imgur.com/F7UDsWO

Edited April 9, 2014 by GentlemanJack

[NathanKell]

Re: overly-draggy gear: Do this for each part (it will zero the drag, which should be fine if the gear retracts into another part).

@PART[FSbomberLandingGear]
{
	@maximum_drag = 0
	@minimum_drag = 0
	@angularDrag = 0
	MODULE
	{
		name = FARBasicDragModel
		S = 0.01
		CdCurve				//Drag coefficient at various angles
		{
			key = -1 0		//backwards
			key = 1.0 0		//forwards
		}
		ClCurve
		{
			key = -1 0		//Lift coefficient
			key = 1 0
		}
		CmCurve				//Moment coefficient
		{
			key = -1 0
			key = 1 0
		}
	}
}

[softweir]

Ok so my CoM is a tiny amount behind the Col around the descent stage. My fuel is still about 20% full at the time i reenter and toggle my air breathing Sabre engine. Should i fix this by moving the wings slightly back to compensate for that?

Here are a couple of pictures of the plane. http://imgur.com/8L0a4CA http://imgur.com/F7UDsWO

Yes. Or, if you use Ship Manifest you can shift fuel it to the most forward tanks.

[GentlemanJack]

Ok, i'll play around with it.

[Dirt_Merchant]

Re: overly-draggy gear: Do this for each part (it will zero the drag, which should be fine if the gear retracts into another part).

@PART[FSbomberLandingGear]
{
	@maximum_drag = 0
	@minimum_drag = 0
	@angularDrag = 0
	MODULE
	{
		name = FARBasicDragModel
		S = 0.01
		CdCurve				//Drag coefficient at various angles
		{
			key = -1 0		//backwards
			key = 1.0 0		//forwards
		}
		ClCurve
		{
			key = -1 0		//Lift coefficient
			key = 1 0
		}
		CmCurve				//Moment coefficient
		{
			key = -1 0
			key = 1 0
		}
	}
}

as always sir, you are on point with the help! many thanks!

[ghimb2000]

That's weird. Stock parts also fail to change/alter the CoL for me. Is this known as well?

[ferram4]

If no stock parts affect the CoL at all, that means that FAR is not installed properly or another mod is interfering with it. All parts will affect the CoL in the editor.

[ghimb2000]

Actually, it's a quirk. It sometimes changes CoL, but sometimes it won't, especially after loading a plane that was created when FAR wasn't installed. I can create a video to show this, but it only occurs sporadically. And the weird thing is, flying with and without the stock parts that don't create CoL leads to the same lift.

[phoenix_ca]

Any word on when MechJeb 2 support will arrive? I do like this mod, but calculating terminal velocity by hand for every rocket and plane to program the ascent computer just...doesn't appeal to me. >.<

[GentlemanJack]

Alright, i fixed by descent problem by moving the wings a bit back and making sure all the fuel is pumped to the front when coming down. Thanks everyone!

[ferram4]

@ghimb2000: I have no idea what's going on then. It sounds like something's horribly breaking, but I've never seen that behavior before. Any errors in the output_log.txt?

@phoenix_ca: Here's a flowchart of what to do; it's very simple. After the fourth entry it's completely speculative, but a very accurate portrayal of what tends to happen.

FAR GUI -> FAR Flight Data -> Bottom of the window -> terminal velocity -> attempt to chase terminal V -> lose control of rocket -> stick closer to prograde next launch -> end up on really tall suborbital or escape trajectory -> abandon chasing terminal velocity as a thing only encouraged by the stock drag model being awful

Further progress report:

It looks like I managed to fix the gear being a problem, the release will be out when I finally get the source on Github and I'm sure that I know what I'm doing. It's moments like these that I'm reminded that I'm an engineer with an affinity for coding, not a programmer.

Edited April 10, 2014 by ferram4

[ghimb2000]

I'll get the output_log.txt when I get back to my PC. But yes, it seems like something is horribly breaking and it only occurs spontaneously. The lift rating disappearing however, happens to me all the time when FAR is installed, even without any mods.

[ferram4]

Well, the lift rating is completely bogus, and it's part of the stock lift system, which FAR removes; it's pretty difficult to simplify everything FAR does down to one number.

[ghimb2000]

Well, the lift rating is completely bogus, and it's part of the stock lift system, which FAR removes; it's pretty difficult to simplify everything FAR does down to one number.

Ok. That's good to know. The lift rating of other mods does show up though (non-stock aerospace parts). Should FAR remove those as well? It's a bit confusing to see some parts offering lift rating while others don't.

[NathanKell]

That means those other mods' parts aren't FAR-compatible, yes. While FAR automatically configures itself for all non-wing non-controlsurface parts, those latter two types of parts need their own hand-made configs.

[ghimb2000]

That means those other mods' parts aren't FAR-compatible, yes. While FAR automatically configures itself for all non-wing non-controlsurface parts, those latter two types of parts need their own hand-made configs.

Should this something be done by other mod developers, or can FAR make some changes on its end to make it compatible with other non-stock aerospace parts?

Not having support for non-stock aerospace parts is a bit of a downer though.