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

[Forty21112]

GIT version? You mean the one that was downloaded at Github?

[Skalou]

hello,

i 've reinstalled far with CKAN and add the mod preconised with:Kerbal-Isp-Difficulty-Scaler

What was the isp parameter before ( just with FAR) : 1vaccum and 1 atmo?

thanks

[NathanKell]

Skaku: correct.

[DaMichel]

GIT version? You mean the one that was downloaded at Github?

Not the one that you get via the Release page. Instead grab the stuff that you get with the Download ZIP button.

https://github.com/ferram4/Ferram-Aerospace-Research/archive/master.zip

The source code will be in there, too, but you just need the things in Gamedata as usual.

Seriously? Did something happen in 0.25 that I missed or is it that I downloaded it wrong?

The default mass of the wings was increased considerably. This probably brings your crafts out of balance. There is now a slider now with which you can adjust the mass. I think about 0.4 is like the old wings. More mass now makes wings less prone to aerodynamic breakup. (I think it was introduced in 0.25 but i'm not sure.)

[Forty21112]

Not the one that you get via the Release page. Instead grab the stuff that you get with the Download ZIP button.

https://github.com/ferram4/Ferram-Aerospace-Research/archive/master.zip

The source code will be in there, too, but you just need the things in Gamedata as usual.

So, which do I take? The whole folder in which the three folders are in? Or the Gamedata only?

[Crzyrndm]

So, which do I take? The whole folder in which the three folders are in? Or the Gamedata only?

GameData only

[Wanderfound]

Okay...

I made a thing.

This thing: http://kerbalx.com/Wanderfound/Kerbodyne%20Dragonfly%20X

And, despite bizarre appearances, it works absurdly well.

The question is: just how unrealistic is this thing?

I know that reverse-sweep wings work in reality (although strength limitations restrict their use) and that leading-edge slats are a real thing. But this is a rather extreme example...

Would something resembling this be possible in reality? If not, what is the limiting factor stopping it?

[Rebelgamer]

The biggest limiter would be the control surfaces on the leading edge. Usually that is limited to flaps only, the last aircraft type I worked on(depot level) the LE flap didn't drop until flap detent was between 2-4(full). Even then, movement time was about 20 seconds to move 6 inches vertically. I believe it has to do with the amount of force the airstream hits the leading edge with, trying to design an actual control surface that could move in sync with the main control surfaces would probably be too heavy to be practical. If you think about it, by mounting on the trailing edge of the wing, the surface only deflects the airstream, it doesn't have to bite into it. It's interesting that it works in KSP though, I'm going to have to give it a try.

Edit: Just looked at your image again, If the surfaces were set to deflect upwards as flaps, it should probably be be pretty stable at high AOA's.

Edited January 21, 2015 by Rebelgamer

[Goddess Bhavani]

I've been away from KSP for a long while and poked around with 0.24+ last year during breaks at work. I ended up piecing together various mad aircraft together on the old FAR versions.

Since I spent literally weeks and months on each aircraft type I couldn't bear to part with them so decided to make a compilation as sort of early-F.A.R. homage. I was wanting to demonstrate the use of spoilers and flaps to the Reddit KSP community too.

[Wanderfound]

The biggest limiter would be the control surfaces on the leading edge. Usually that is limited to flaps only, the last aircraft type I worked on(depot level) the LE flap didn't drop until flap detent was between 2-4(full). Even then, movement time was about 20 seconds to move 6 inches vertically. I believe it has to do with the amount of force the airstream hits the leading edge with, trying to design an actual control surface that could move in sync with the main control surfaces would probably be too heavy to be practical. If you think about it, by mounting on the trailing edge of the wing, the surface only deflects the airstream, it doesn't have to bite into it. It's interesting that it works in KSP though, I'm going to have to give it a try.

Edit: Just looked at your image again, If the surfaces were set to deflect upwards as flaps, it should probably be be pretty stable at high AOA's.

The forward surfaces are set with a -100% AoA deflection; any time that they aren't being actively disturbed, they hold themselves parallel to the airstream. And it is indeed extremely stable at insane AoAs.

This is a slightly more conventional design using canards with a similar setting; it should demonstrate what I'm talking about:

That picture is at neutral stick, not trying to pull the nose down; it flies stably in that posture (the canards are parallel to the airstream, you can figure the AoA from that) hands-free.

[Rebelgamer]

Nice, and I see what your talking about too. I haven't really messed with the AOA setting too much myself.

On a real aircraft you could probably do something like that where the entire surface moves to stay parallel to the airflow, which would be a lot simpler than just the leading edge. The only issue I could see with that would be ensuring airflow to the engines at high AOA's.

[tetryds]

Would something resembling this be possible in reality? If not, what is the limiting factor stopping it?

Why do you think that your design is extreme at all?

Despite of the several simplifications and assumptions that FAR makes, it's surprisingly accurate, so yes your plane would likely fly in real life if it's controls worked like ingame ones.

Ofcourse, in real life the mass distribution of the aircraft would be very different, as well as some other things, but if you managed to replicate it it would fly very simmilarly to ingame.

You also have a ton of artificial stability there, which helps a lot.

The main limiting factor is structural integrity, but that is not the only thing.

The "standard" aircraft design has a lot of documentation into it, we know exactly how to place things and how such configurations will behave.

There are lots of engineering problems that already have their solutions for the current design style, if you developed an aircraft like that it would be very complicated and expensive.

Another massive problem is aesthetics, really, even though it performs well it's super ugly, no one expects a plane to look like that, and no one will ever ride an airliner which looks like that plane at all.

If you don't believe me, check both the F-35 story, as well as the Boeing X-48, the later is an awesome aircraft, even though it requires fly-by-wire to fly it performs well, is efficient, resistant and have room for a crapload of cargo/people...

There are more details and some other stuff to this, but yes these weird designs can fly just fine, if you built an RC plane that looks like yours (and managed to add the artificial stability to it) I don't see it having many issues in flight.

I have project to prove that anything sane can fly with FAR, you just need to tweak it well, really.

Example: http://forum.kerbalspaceprogram.com/threads/107213-Article-Overhauled-Aerodynamics?p=1667948&viewfull=1#post1667948

Edited January 21, 2015 by tetryds

[starikki]

Why do you think that your design is extreme at all?

Despite of the several simplifications and assumptions that FAR makes, it's surprisingly accurate, so yes your plane would likely fly in real life if it's controls worked like ingame ones.

Ofcourse, in real life the mass distribution of the aircraft would be very different, as well as some other things, but if you managed to replicate it it would fly very simmilarly to ingame.

You also have a ton of artificial stability there, which helps a lot.

The main limiting factor is structural integrity, but that is not the only thing.

The "standard" aircraft design has a lot of documentation into it, we know exactly how to place things and how such configurations will behave.

There are lots of engineering problems that already have their solutions for the current design style, if you developed an aircraft like that it would be very complicated and expensive.

Another massive problem is aesthetics, really, even though it performs well it's super ugly, no one expects a plane to look like that, and no one will ever ride an airliner which looks like that plane at all.

If you don't believe me, check both the F-35 story, as well as the Boeing X-48, the later is an awesome aircraft, even though it requires fly-by-wire to fly it performs well, is efficient, resistant and have room for a crapload of cargo/people...

There are more details and some other stuff to this, but yes these weird designs can fly just fine, if you built an RC plane that looks like yours (and managed to add the artificial stability to it) I don't see it having many issues in flight.

I have project to prove that anything sane can fly with FAR, you just need to tweak it well, really.

Example: http://forum.kerbalspaceprogram.com/threads/107213-Article-Overhauled-Aerodynamics?p=1667948&viewfull=1#post1667948

Well being able to fly it and being able to fly it with SAS off (along with the supper powerful reaction wheels) at full envelope are two massively different things.

But yes it is totally feasible for most designs, I've made some thing like a X-48/ X47B and its handling falls well within Cooper Harper rating level I, without SAS and reaction wheels. But it takes knowledge of real aircraft design process, and lots of tweaking.

The real beauty of the new mods is that, such aircraft only has 18 parts! With P/Parts and Bac9's new P/Wing mod, happy flying and no more graphic card meltdown.

[tetryds]

Well being able to fly it and being able to fly it with SAS off (along with the supper powerful reaction wheels) at full envelope are two massively different things.

But yes it is totally feasible for most designs, I've made some thing like a X-48/ X47B and its handling falls well within Cooper Harper rating level I, without SAS and reaction wheels. But it takes knowledge of real aircraft design process, and lots of tweaking.

http://ww2.sinaimg.cn/large/4144fe13jw1eohsa8pv4qj21hc0u0nci.jpgThe real beauty of the new mods is that, such aircraft only has 18 parts! With P/Parts and Bac9's new P/Wing mod, happy flying and no more graphic card meltdown.

You mean CPU meltdown

About SAS, yes, that is true, but most aircrafts can be made to work without SAS at least to a point, you just need to know your cruise conditions and apply propper trimming, either on editor or inflight.

If that is not possible then there is something wrong with the design, double the tail then double again then double one more time

Nice plane.

Here is one of mine, it's not a replica of anything:

The biggest problems with low altitude transonic designs is the high altitude yaw instability, but that is just because bigger vertical stabilizers make it look ugly, and it does not really need them.

Edited January 21, 2015 by tetryds

[Toastedbuns]

Quick question amiss this heated aerodynamics discussion here from a new FAR user.

Restarted my career mode just to play it and one problem immediately arises. My rockets keep turning upon launch.

I just want to see if I'm right for future designs, but is it because my CoL is higher than my CoM? Everything else is as imperfectly perfectly symmetrical as things can get. Seal of approval, there.

[Mekan1k]

Quick question amiss this heated aerodynamics discussion here from a new FAR user.

Restarted my career mode just to play it and one problem immediately arises. My rockets keep turning upon launch.

http://i.imgur.com/4SkHTxT.jpg?1

I just want to see if I'm right for future designs, but is it because my CoL is higher than my CoM? Everything else is as imperfectly perfectly symmetrical as things can get. Seal of approval, there.

Yes. CoL should always be behind CoM- unless you want to do somersaults...

[HoneyFox]

The forward surfaces are set with a -100% AoA deflection; any time that they aren't being actively disturbed, they hold themselves parallel to the airstream. And it is indeed extremely stable at insane AoAs.

This is a slightly more conventional design using canards with a similar setting; it should demonstrate what I'm talking about:

http://i1378.photobucket.com/albums/ah120/craigmotbey/Kerbal/Beta/Kerbodyne%20Showroom/Stratos%20N/screenshot1017_zps41e7d63c.jpg

That picture is at neutral stick, not trying to pull the nose down; it flies stably in that posture (the canards are parallel to the airstream, you can figure the AoA from that) hands-free.

I don't see any big issue with this aircraft being able to be stable at that AoA. (at least for pitch stability)

You setup the canard with -100% AoA, that means you can almost ignore them (because they always have ~0 deg local AoA) when not given any pitch input. Your wings are installed at pretty rear place, but your engines are quite heavy as well, especially that NTR. The aircraft's fore body can generate quite some lift as well, so the overall Cm at this AoA might be pretty close to zero. Better check your Cm curve graph @40 deg of AoA.

Last thing, it seems like your aircraft is flying at pretty high altitude, thinner air make it less prone to aero-related instability issue.

Edited January 22, 2015 by HoneyFox

[tetryds]

Quick question amiss this heated aerodynamics discussion here from a new FAR user.

Restarted my career mode just to play it and one problem immediately arises. My rockets keep turning upon launch.

http://i.imgur.com/4SkHTxT.jpg?1

I just want to see if I'm right for future designs, but is it because my CoL is higher than my CoM? Everything else is as imperfectly perfectly symmetrical as things can get. Seal of approval, there.

Before you unlock wingparts to stick to the bottom what you can do is go up straight, slower, then make the turn like you would on the stock game. It's less efficient but also less deadly.

[DaniWesNL]

I keep having massive issues with planes breaking. Doing around 200 m/s, make a slight adjustment pulling no more than 6 or 7 G, and BAM entire plane disintegrates. Every single joint snaps.

I like the fact this mod does aerodynamics better than the base game, but I would really like my planes to be stronger than match sticks.

Guess I'll use "the option to disable aerodynamic failure" in the cheats menu.

[blowfish]

6-7g is quite a lot. Is it only wings that are snapping or other things as well? And how much dynamic pressure are you dealing with?

[tetryds]

Blowfish is right.

You can also make your wing parts stronger by increasing their weight on the tweakables menu.

[Wanderfound]

I don't see any big issue with this aircraft being able to be stable at that AoA. (at least for pitch stability)

You setup the canard with -100% AoA, that means you can almost ignore them (because they always have ~0 deg local AoA) when not given any pitch input. Your wings are installed at pretty rear place, but your engines are quite heavy as well, especially that NTR. The aircraft's fore body can generate quite some lift as well, so the overall Cm at this AoA might be pretty close to zero. Better check your Cm curve graph @40 deg of AoA.

Last thing, it seems like your aircraft is flying at pretty high altitude, thinner air make it less prone to aero-related instability issue.

Yes to all of the above.

I was more wondering about the practicality of the leading edge slat controls; the AoA thing is just the AoA setting working as it should.

[DaniWesNL]

6-7g is quite a lot. Is it only wings that are snapping or other things as well? And how much dynamic pressure are you dealing with?

Every single joint snaps, it starts with the cockpit detaching from the fuselage, then the parts of the fuselage snapping and the wings breaking off.

And though the G-forces are indeed quite strong, it shouldn't be nearly a catastrophic structural failure.

Don't know about the dyanmic pressure. I've only used FAR since yesterday, tried it for 4 hours, but kept getting this issue with MK2 (stock) and S2 (from B9 iirc).

So I haven't actually used the mod to display aircraft stats.

Only really used Engineer to make sure I had enough TWR and made sure I followed these guidelines:

http://forum.kerbalspaceprogram.com/threads/52080-Basic-Aircraft-Design-Explained-Simply-With-Pictures

[starikki]

Wondering if we can do anything to increase Cd0 when landing gears are deployed?

It's a little bit annoying when we have to add spoiler even on very light aircraft in order to

EDIT: Firespiter and its FSWheel module seems to have deployed drag??

Edited January 22, 2015 by starikki

[taniwha]

DaniWesNL: S2 and B9 parts are pretty big, which means you have a rather massive plane (10s, possibly 100s of tons). At 6g, your plane's wings (and everything else, really) is trying to support 60-600 tons. With any length to your plane, you will have bending forces and thus buckling (and thus dramatic aerodynamic failure) is quite possible.

Also, raw Gs is no measure of the stresses your plane is undergoing. 6-7g on a 3t plane is nothing (180-210kN spread over your plane), but for a 100t plane, that's 6000-7000kN spread around (using simple 1g = 10m/s² instead of the correct 9.81: easier mental math). However, where are those kN concentrated? If close to the CoM, then buckling is less likely (extremities might not have sufficient support to not fall off). If far from the CoM, failure is almost guaranteed (very high torque near the CoM).

Another also: I have had aerodynamic failure without pulling any real Gs: I fully deployed my spoilers (strength tuned down) with an EAS of over 150m/s: my spoilers came off. I've also had my elevators snap off for similar reasons (I don't remember how fast I was going, but I did pull back rather hard on my stick and the elevators bought the farm).