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

[jrandom]

Yea I'm trying to decide what is good. Is there any good rule of thumb? Like the CoM ball resting fully on the forward axis indicator of the CoL? Currently where it is you can see the axis sticking out, and I'm thinking of moving the CoM forward just enough to cover it up

The CoL can have definite gap between it and the CoM. You want it closer for supersonic flight since the CoL moves backwards when you're moving faster than the speed of sound. (By how much I do not know.)

What you've got in your images I would consider super close. Your pitch control will be incredibly sensitive. The last time I built a plane like that, it was nearly unflyable until I got way up in the atmosphere and was flying around mach 2 or so.

Edit: For example, here's a craft that flies great at subsonic speeds, and pretty well when supersonic, although it loses pitch control in the neighborhood of 23km (in RSS/RO, not sure what the ceiling would be in stock KSP) at Mach 3 due to the CoL position. It would be capable of pitch control at those altitudes if I moved the CoL closer to the CoM, but I would also get more unstable flight when subsonic as a result:

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Edited June 27, 2014 by jrandom

[ThorBeorn]

@Ferram: Is it/will it be possible for FAR to detect parts that are clipped into other parts and only apply drag to the outward facing surfaces? If not, could it be possible to manually tell FAR what parts are clipped or something? I think part clipping is necessary otherwise we are limited to basically tube shaped fuselages only.

Edited June 27, 2014 by ThorBeorn

[Hodo]

@Ferram: Is it/will it be possible for FAR to detect parts that are clipped into other parts and only apply drag to the outward facing surfaces? If not, could it be possible to manually tell FAR what parts are clipped or something? I think part clipping is necessary otherwise we are limited to basically tube shaped fuselages only.

There is a plugin that gives you hollow utility storage areas that fit in line with the 1.25 and 2.5m parts. And thats not the only thing there is even the B9 cargo bays which also work for larger craft. I use them both all the time to place oxygen tanks for ECLSS and batteries that I don't want slapped to the outside of the aircraft and to hide my MJ module.

[DebatedNothing]

I'm having an issue that I believe to be to do with FAR in 23.5. Basically whenever there's an aerodynamic failure ending my flight, I cannot revert to anything or return to the space centre. Could be due to interplay issues with other mods, but the issue is completely isolated to FAR aerodynamic failures.

[ayana]

Edit: wrong thread

[ThorBeorn]

I'm having an issue that I believe to be to do with FAR in 23.5. Basically whenever there's an aerodynamic failure ending my flight, I cannot revert to anything or return to the space centre. Could be due to interplay issues with other mods, but the issue is completely isolated to FAR aerodynamic failures.

Delete Tweakable Everything if you have that mod. It caused something similar to me.

[Hodo]

I'm having an issue that I believe to be to do with FAR in 23.5. Basically whenever there's an aerodynamic failure ending my flight, I cannot revert to anything or return to the space centre. Could be due to interplay issues with other mods, but the issue is completely isolated to FAR aerodynamic failures.

I have not had this related to FAR but I have had this. I have never had anything other than FAR and a few other mods, but I have ruled out FAR and DRE as the causes. I think it was a KSP issue.

[darkstar80]

I've got a bit of an issue that I'm wondering if you guys have run into. I was working on building a plane recently and saved it to come back to it later. When i reloaded it last night I was unable to get the CoM marker to show up. Pushing the button had no effect, and when I did a "sweep AoA" the graph just had a bunch of yellow lines going up and down covering the window. When I load up a different plane or start a new one the CoM and graph works fine. Seems like a bug of some sort with the save file of that particular craft.

Anybody run into this before?

[DebatedNothing]

I have not had this related to FAR but I have had this. I have never had anything other than FAR and a few other mods, but I have ruled out FAR and DRE as the causes. I think it was a KSP issue.

In that case is there a way to fix it without restarting KSP or not?

- - - Updated - - -

Delete Tweakable Everything if you have that mod. It caused something similar to me.

Don't have that mod :/

[sasabune]

I've got a bit of an issue that I'm wondering if you guys have run into. I was working on building a plane recently and saved it to come back to it later. When i reloaded it last night I was unable to get the CoM marker to show up. Pushing the button had no effect, and when I did a "sweep AoA" the graph just had a bunch of yellow lines going up and down covering the window. When I load up a different plane or start a new one the CoM and graph works fine. Seems like a bug of some sort with the save file of that particular craft.

Anybody run into this before?

Edited June 29, 2014 by sasabune

[nubeees]

It seems that if I have Ferram on, I can't put fins on my rocket or else the game entirely flips out and shoots me into space at ridiculous speeds...

*edit

I think I found a suspect for these issues; I have a newer version of module manager then what comes with the download... I have no idea if it is whats causing the problem though.

*edit 2

I downgraded module manager to the version Ferram uses, it seems to work fine now. Looks like Ferram needs an update.

*edit yet again

Nevermind that, My game is flipping out again. O.o

Edited June 29, 2014 by nubeees

[Drew Kerman]

I've got a bit of an issue that I'm wondering if you guys have run into. I was working on building a plane recently and saved it to come back to it later. When i reloaded it last night I was unable to get the CoM marker to show up. Pushing the button had no effect, and when I did a "sweep AoA" the graph just had a bunch of yellow lines going up and down covering the window. When I load up a different plane or start a new one the CoM and graph works fine. Seems like a bug of some sort with the save file of that particular craft.

Anybody run into this before?

This happens to me if I use any of the B9 engines on a plane.

Might be an issue with electric charge on the engines. Try adding this to a MM config file: (although it probably won't fix your current craft file it may prevent future problems)

@PART
[*]:HAS[@MODULE[ModuleEngines],@RESOURCE[ElectricCharge]]
{
    @RESOURCE[ElectricCharge]
    {
        %isTweakable = false
        %hideFlow = true
    }
}

It seems that if I have Ferram on, I can't put fins on my rocket or else the game entirely flips out and shoots me into space at ridiculous speeds...

*edit

I think I found a suspect for these issues; I have a newer version of module manager then what comes with the download... I have no idea if it is whats causing the problem though.

*edit 2

I downgraded module manager to the version Ferram uses, it seems to work fine now. Looks like Ferram needs an update.

*edit yet again

Nevermind that, My game is flipping out again. O.o

Most likely not MM related, the newest MM has been out for several weeks now and no one else has seen any problems with it

[Starwaster]

It seems that if I have Ferram on, I can't put fins on my rocket or else the game entirely flips out and shoots me into space at ridiculous speeds...

*edit

I think I found a suspect for these issues; I have a newer version of module manager then what comes with the download... I have no idea if it is whats causing the problem though.

*edit 2

I downgraded module manager to the version Ferram uses, it seems to work fine now. Looks like Ferram needs an update.

*edit yet again

Nevermind that, My game is flipping out again. O.o

Module Manager doesn't do things like that. You could have saved yourself some trouble

(things you INSTALL with Module Manager might do that though...)

[nubeees]

Module Manager doesn't do things like that. You could have saved yourself some trouble

(things you INSTALL with Module Manager might do that though...)

Huh... I'm not sure then, I suspect Ferram mostly because it was the default fins that were causing the game to spontaneously forget physics and fling me into space stupendously fast...

[Starwaster]

Huh... I'm not sure then, I suspect Ferram mostly because it was the default fins that were causing the game to spontaneously forget physics and fling me into space stupendously fast...

You mean as in stock? I'd think other people would have reported that given how many people use it and for how long they've been using it.

You should post screenshots of the craft, and go over how you installed. List other mods you have installed (one of them could be responsible) and Maybe post your output_log.txt file

[AdmiralTigerclaw]

Ok I think I'm close. Looking for some final advice. Please keep in mind this is under a career game with financing, so I haven't researched a lot of parts to use and haven't put much science towards aerodynamics in the tech tree. So I have limitations and this is the best I think I can do with what I have to get a hybrid aircraft. The idea is for it to power climb on the jet engines and glide down slowly with the electric propellers, doing this a few times until fuel runs low and it needs to return. Honestly don't know if the concept is viable but I'm trying to find out and learn a bit more about plane building in the process.

I just flew a test flight that had my nose lift and my rear end hit the ground and blew up a few seconds into my takeoff roll no doubt because my gear was too close to the CoM. I noticed when I 2x physical warp the plane almost tips over backwards. Would it be a good guide to be able to 3x or 4x physical warp without the aircraft tipping back on its rear as a good indication of where to place the gear relative to the CoM? I also think the propeller thrust being under the CoM helped the nose come up and I should instead takeoff on jet power alone at first rather than move the gear too far back to make it harder to lift off. I could also angle the canard wings down a bit.

The test was flown with only the main fuselage/nose cone and engine fuselage/nose cones filled with fuel.

http://imgur.com/a/yS1rT

Wow... Your plane is grossly overweight for its size. 17 tons at a TWR of 0.3? It's no wonder you can't get that thing off the ground. It's a brick. Consider the A-10 Thunderbolt II weighs in the same range WITH COMBAT PAYLOAD.

Looking at your AoA sweep images, your L/D (Green Line) is terrible. And with a TWR less than half the vehicle's weight, you could up-end that thing and it wouldn't fly.

Also, your control surface settings show another problem. When you pull back on the stick, your L/D drops. Looking at the image, I see that this corresponds to aft stick input for pulling back on the nose. Your aft-wing control surfaces fan up and behave more like spoilers instead of elevators. This makes your already terrible lift problem even worse.

Read that green line on your AoA sweep, your L/D ratio doesn't even hit 1 until you're pulled back to 15 in no-control-surface-input flight, and it doesn't even hit 1 when you're pulling aft on the stick. L/D is the efficiency of your plane's ability to fly. Technically, anything can fly if you attach enough engine to it, but we call those things 'rockets'. If your L/D isn't even hitting 1, that means you're not breaking even with your lift ability vs your vehicle drag. Which means, if you're flying, it's ALLLLL engine. Which you don't have... because... Well TWR is 0.3. You couldn't launch a bottle rocket with that.

So in a nutshell:

1: Lose weight... a LOT of it. Go with the props, or the jets and design around one or the other. You'll either lose the fuel weight if you go electric, or the electric engine weight if you keep the jets.

2: You need to get your elevators away from your wings so they don't behave like spoilers when you pull back on the stick. Try making your V-stabs shallower and enable elevator control on them. If you're CoM is close enough to your CoL and your gear are in the right place, that shouldn't require very much elevator response for rotation.

3: Convert the control surfaces on the main wing closest to the inside into flaps. That should give you a little extra play for takeoff.

4: Pay attention to that CoL line. You want a sharp climb above 1 well ahead of ten degrees.

5: BONUS: Keep an eye on that yellow line. When it goes positive, you tend to die.

[darkstar80]

Thanks for the advice, I'll give it a try!

[nubeees]

Alright, I removed the Dangit mod, and my ship seemed to have loaded fine. I'll have to do some more testing before I know if that really fixed it though...

[Starwaster]

Is there a way to stop wings attached to a cargo hold from being shielded? Ideally, some sort of override? Or a way to mark designated stack nodes as never shielded?

(this is for KSO25. Someone is trying to write up a FAR config for it. They've tried moving the nodes but sometimes it still seems to want to shield the wings)

[ferram4]

That would be because (IIRC) the KSO has foolish placement for the origin of the main wings, which results in the location that the wings use to determine if they're shielded or not not actually being anywhere near where you would think they should be for those wings. The only solution is to shift the mesh around in a config so that the origin is centered along the wing root, not in the cargo bay like I know it tends to be.

[Starwaster]

That would be because (IIRC) the KSO has foolish placement for the origin of the main wings, which results in the location that the wings use to determine if they're shielded or not not actually being anywhere near where you would think they should be for those wings. The only solution is to shift the mesh around in a config so that the origin is centered along the wing root, not in the cargo bay like I know it tends to be.

I think that's what they've done but it still gets shielded.

Can I suggest an addition to FARCargoBayModule in the future? A list of nodes that FAR will ignore parts that are attached to them?

[Alshain]

Is there a guide somewhere to understanding at least a basic level of the stability derivatives. Or even a guide to translate "this is the effect I'm getting, what do I do to fix it?". I mean, really it's a couple dozen numbers on a screen and your trying to get them green at different speeds but there is no explanation for what to do if say Zu is red, what do I move or change to fix it? Randomly moving stuff around in the hopes that it fixes but never does it is incredibly boring.

[Starwaster]

Is there a guide somewhere to understanding at least a basic level of the stability derivatives. Or even a guide to translate "this is the effect I'm getting, what do I do to fix it?". I mean, really it's a couple dozen numbers on a screen and your trying to get them green at different speeds but there is no explanation for what to do if say Zu is red, what do I move or change to fix it? Randomly moving stuff around in the hopes that it fixes but never does it is incredibly boring.

There's been some stuff written on it for the wiki. Check front page for link. First post.

[Alshain]

There's been some stuff written on it for the wiki. Check front page for link. First post.

I've read the wiki, it's kinda useless.

The dynamic stability window is kind of mysterious. Green is good; red is bad.

The most useless thing that could be written in a wiki. If a wiki has to say that, there might as well not even be a wiki.

The question still stands, anything that actually helps understand what they mean or how to tweak each individual one. Not "make them green", but how to make them green. I'm not an aircraft designer in real life, those numbers are meaningless and if I move one part that might change one thing to green, 3 others go red, because I don't know what they mean.

I wish someone would make a "gamers" aerodynamic mod. Something not impossible to understand unless you design aircraft for a living like FAR, and something not so stupid you can fly a box like stock. We basically have a choice of one ridiculous extreme or the other.

Edited July 1, 2014 by Alshain

[jrandom]

I would hardly call FAR a ridiculous extreme. While I too would like a description of what to do in the case of red numbers, you can still get an awful lot of successful design done just by looking at the first tab's graphs, keeping your lift/drag ratio sane and making sure the yellow line does not ever rise above 0.

I don't want a dumbed-down atmosphere. It's way less interesting.