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

[tetryds]

This may be another case of user error, but I'm noticing massive amounts of drag in the upper atmosphere. I've tried a number of planes with both stock and mod parts, made sure not use any cargobays, or janky stuff that can get in the way. Looking at the drag indicator at low-level flight, shows a bright nose, with everything else being much dimmer, and during my ascent through the lower to middle atmosphere, the flight characteristics bear that out.

However, when I get into the upper atmosphere, get up to Mach 7+, and push my Ap up to 120k, the plane is now a solid yellow mass of draginess. Is that a word? I have to keep burning more fuel to keep the Ap up. Most recently, at a height of 55 km, I finished another burn to raise up the Ap, and kept the nose prograde. In about ten seconds, the Ap had dropped from 120k to 84k. This happening with any plane, in any configuration, and the excessive drag is only present in the upper reaches of the atmosphere.

Hope that makes sense. Is this a FAR issue, or my issue? Anyone else experiencing this?

You should pay more attention to the changelogs.

[Beetlecat]

You should pay more attention to the changelogs.

It sounds like that changed feature is working as intended!

[Shadow_Spark]

I have this problem with FAR and NEAR where in the spaceplane hangar, the center of lift is completly messed up making it near impossible to know how to fix issues with my planes.... Any help?

[Voculus]

You should pay more attention to the changelogs.

Indeed. Indeed.

[Guest]

Thanks for updating this so quickly ferram4

You're one heck of a modder.

Skin friction drag now varies with Reynolds number; this means much higher skin friction drags at higher altitudes

Do you mean by skin that clipped parts won't be considered as the surface of the craft or partly if they are half clipped? Or are you planning such a feature?

And do you mean that FAR now will differentiate laminar from turbulent flow based on overall wing shape and altitude/speed?

It intrigues me because air in ksp isn't really simulated as a proper fluid right?

Edited December 17, 2014 by RevanCorana

[Hodo]

It intrigues me because air in ksp isn't really simulated as a proper fluid right?

No but its stock atmosphere does... LOL!

[Guest]

Interesting, so stock ksp air is simulated as a fluid and FAR removes it? Doesn't help stock to be realistic lol. It adds lift for each layer of wings without caring if there is actual airflow on them, but looks like FAR either..

Confused

[biohazard15]

@biohazard15: And followed installation instructions completely, deleting the entire old FAR folder?

There was no old FAR folder, as it's a new KSP install (I'm always do a fresh install in its own folder when a new version comes out - helps to maintain backups).

Forgot to add MM (v. 2.5.4) to the mods list.

[Empiro]

Does anyone have good advice for spaceplanes with the new drag models? It definitely feels like it's going to be a much bigger challenge to get any sort of SSTO spaceplane that can lift a heavy payload to orbit now that you need 30-40% more delta-V in your LFO stage to make orbit.

[innociv]

Are you entering altitude in kilometres or metres?

Ah. I was trying to put in 22000 km instead of meters.

So doing that causes that bug.

[cantab]

Interesting, so stock ksp air is simulated as a fluid and FAR removes it?

Errr, no. The stock "aerodynamics" are severely flawed, the air behaves more like a forcefield than any real fluid.

Ferram Aerospace Research replaces this with a more realistic model. I believe though that it is not attempting to simulate actual fluid flow, which would be extremely demanding on the CPU, but rather approximate it reasonably well with simpler calculations.

[Guest]

FAR now will differentiate laminar from turbulent flow based on overall wing shape and altitude/speed?

It looks like my F-49 always break when it start to move into turbulent flow

but rather approximate it reasonably well with simpler calculations.

I see exactly what you mean by "forcefield", and I was bored of this, now I just wonder what are the limits FAR in order to make the most maneuverable lightweight fighter for fun

It gets tricky because structural parts have drag too.

Do you think an airfoil shaped frame made of several hardpoints would have any benefical properties? Or is it in the aproximation range.. and will just add more drag overall, (but even if this means more drag it can make the plane handle differently). I understand that visual idea and actual drag values are different in KSP btw

I'm not sure if an airfoil without laminar fluid simulation makes any sort of sense

Something like this

Or this

Edited December 17, 2014 by RevanCorana

[ferram4]

@Rayakdos: Upload logs. I still suspect an error outside of FAR though, I can't reproduce the issue.

@Voculus: I'm not seeing drag anywhere near that high; yes, skin friction drag is higher, but isn't likely enough to eat that much energy off of your vehicle at 55 km. I just tried something similar with a spaceplane to 95 km, engine cutoff at 40 km and it only dropped to 92.

@Shadow_Spark: Well, what are the reproduction steps and where are the logs? I can't help until you provide that so I know what I'm dealing with.

@Revan_Corona: No, FAR doesn't account for part clipping. It's horribly complicated to deal with that kind of geometrical mess.

@Empiro: Same as always, dV requriments haven't changed significantly, people are just overreacting.

@Anyone having issues: I want FULL details. Entire logs, entire reproduction steps, your operating system, and everything you did in the process of installation. Anything less doesn't get addressed until I get those details.

[Rakaydos]

Imgur is "over capacity" so I cant screenshot, but...

[Error]: ...no FARBasicDragModel module found on part definition. Skipping...

[Warning]: [Part]: PartModule FARBasicDragModel at SmallGearBay, index 5: index exceeds module count as defined in cfg.

Looking for FARBasicDragModel in other indices...

[Error]: ...no FARBasicDragModel module found on part definition. Skipping...

[Warning]: [Part]: PartModule FARBasicDragModel at SmallGearBay, index 5: index exceeds module count as defined in cfg.

Looking for FARBasicDragModel in other indices...

[Error]: ...no FARBasicDragModel module found on part definition. Skipping...

[Warning]: [Part]: PartModule FARBasicDragModel at RCSBlock, index 1: index exceeds module count as defined in cfg.

Looking for FARBasicDragModel in other indices...

...ect.

There's some earlier stuff about tech tree not having "unresearchable" which might be related to another mod (I have Mechjeb and Stage Recovery instaled), and somethig about the highlighting system not working.

[ferram4]

Those errors are not a problem.

Don't go to imgur, that won't hold the entire log. Upload the actual text log.

[Rakaydos]

Is there an easy way to copy the whole log? in the Alt12 debug window, I could only highlight one entry at a time.

Regardless, I'm trying the hard reset at the moment- pulling my Saves folder out of KSP, deleting everything else, and redownloading KSP from scratch. Plan is to replace the Saves folder, put FAR back in, Mechjeb (which is part of my craft) and load m craft.

[biohazard15]

@Anyone having issues: I want FULL details. Entire logs, entire reproduction steps, your operating system, and everything you did in the process of installation. Anything less doesn't get addressed until I get those details.

Here you go - https://drive.google.com/file/d/0B-l1kSh8cSSAYjl4N0hMS1lCeGc/view?usp=sharing

KSP 0.90, FAR 0.14.5, MM 2.5.4.

Part shielding info is enabled in config.

Reproduction:

- Go in VAB, grab any part, right-click on it - you don't see "IsShielded" (or "Parts shielded" in case of cargo bays) info item

- Launch craft, right-click on any part - now you see "IsShielded" info

[NathanKell]

Rakaydos:

1. Zip up the log.

2. Go to dropbox and upload (or pick whatever file-sharing site you like)

3. ???

4. Profit!

[Rakaydos]

Rakaydos:

1. Zip up the log.

2. Go to dropbox and upload (or pick whatever file-sharing site you like)

3. ???

4. Profit!

The log is a file? What folder?

[Rebelgamer]

For windows, its in the KSP_Data folder, named output_log.txt

Linux/mac is named player.log, not sure where it is(I assume the same location, but not sure).

[Renegrade]

@Anyone having issues: I want FULL details. Entire logs, entire reproduction steps, your operating system, and everything you did in the process of installation. Anything less doesn't get addressed until I get those details.

No issues here, seems quite spiffy, and thanks again for the fast update (I'm also really digging the new axis-independent control surface scaling)

[ferram4]

@biohazard15: Reproduced, it's fixed if the vessel part list is changed in some way. I'll see what I can do.

[Rakaydos]

https://www.dropbox.com/s/gr67j954bn4byu6/output_log.txt?dl=0

Process:

Installed KSP

Added FAR 14.5 and moduelmanager to Gamedata folder

Added Mechjeb to Gamedata folder

Added "ARM sandbox" folder to Saves folder (Drobbox: https://www.dropbox.com/sh/cqy7mjg7bzhk7sr/AAAhmHijuuWFlXE7o1xki7q5a?dl=0)

Opened KSP

Opened ARM Sandbox file

Opened Spaceplane hanger

Opened craft "Gryphon v1"

Opened FAR Aero analysis and ran a scan.

Changed flap setting and ran again (no significant change in flight data) (repeat a few times)

Launch the vessel

Right click a flap to see flap setting.

Use action groups to change flap settings. (the flap settings in the right click box change, but not the positions of the flaps.

Close KSP.

OS is Windows 8

Edited December 18, 2014 by Rakaydos

[Voculus]

Reinstalled KSP.

Installed FAR.

Installed Toolbar

Installed MM 2.5.4

Output.log

Without Mechjeb or Engineer, it was difficult to get firm numbers, but the same excessive drag at high altitude situation continues. This particular craft was the lightest of all the spaceplanes I've tried. The last image in the album below shows the ship a few seconds after engine cutoff, with the Ap then at 150km. After reaching space, it had fallen to 114km. Previously, the heavier, larger ships, presumably with much more surface area, suffered much more severe drag.

Javascript is disabled. View full album

I'm sorry I don't have any math or anything more solid than my gut feeling that something is off, but there you have it. If it's the new normal, I'll learn to live with it. If not, I'd love to fix it.

[Sampa]

Ok, fine...since my favorite mod in development is temporarily out of commission (CSS), I'll give this mod another try...