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

[B15HOP_xmen]

2 minutes ago, ss8913 said:

I've not had that experience with far.. perhaps your main gear are too far aft of your center of mass?

I tend to have them further back. It was something I look at so you're on the money there. Issue being of course, too far forward and it limits my angle of attack on take off. My guess is that is a common problem with high altitude designs. Otherwise having huge stalk legs hanging out looks a bit crazy.

[stellargeli]

On 12/11/2016 at 4:24 PM, ss8913 said:

In the meantime, this is still worlds better than stock aero, and ferram4 deserves a ton of credit for making this happen.

I did give him credit.  I said its an awesome mod and I enjoy what it brings to KSP.

My point was that it can only approximate RL up to a point and people should not expect it to be 100% accurate, differing airfoils for different aircraft being an example of a limitation, among many limitations.

On 12/11/2016 at 11:19 PM, blowfish said:

FAR assumes that all airfoils are thin, supersonic airfoils (I don't remember the exact shape).  That's certainly not realistic for all planes but also far from made-up.

I'm glad to learn that there is a specific airfoil shape being used in the modelling. I assumed it was either a single shape, or just a set of characteristics taken from an RL shape. Either way, my point still stands.  "Made-up" was probably not the best best choice of words, but hopefully you can see what I'm driving at.  No offense was intended, and I didn't intend to imply that FAR is somehow sloppy or fantasy.

I'm not saying anything bad about FAR, I'm pointing out that it has limitations and people shouldn't go overboard with their expectations, that's all.

I love FAR, please don't misunderstand me.  It is one of my favorite mods, and as both an engineer and a programmer I have a lot of respect for the job ferram4 has done in creating it. 

On that note (and NO, I am not asking ferram4 to do this, his mod is awesome as is and I am grateful for having it to use, and I would never ask someone to do a bunch more work for free), I'm wondering if it would be possible to create a companion/addon for FAR that would allow you to select different airfoil shapes.  Then you could have that Cessna that flies more like a Cessna, while keeping your supersonic type craft.  That is something I might be willing to put some time into if I knew 1) it can be done, and 2) I could bug someone with questions while working on it.  I've been looking for a mod project to work on (new to KSP modding) and that would certainly be something I would enjoy trying to create.  That, or working on a mod that makes helicopters work like actual helicopters.  Not sure which of those two would make me pull out more hair...

 

Edited December 13, 2016 by stellargeli

[kcs123]

3 hours ago, B15HOP_xmen said:

So does FAR use ground effect?

Latest known working version of FAR no. If you search trough thread, you will find that is planed along with wing overhaul part of code.
If there is no so many breaking changes between KSP updates we would see it much sooner. Until then we can only be patient and wait.

[monstah]

On 10/12/2016 at 0:29 AM, ferram4 said:

Now, behave while I try to figure out all the remaining things wrong with this monster.  Every time I look here there are multiple moderator posts about cleaning things up.  I don't want the thread locked (especially because it'll be a pain when I finally go to update) so don't give the moderators reason to do so.

We're keeping an eye on things, worry not!

[paul23]

Just to shed some light on realism:

 

In reality aircraft never use ground effect. - At least while designing. (And even in reality it is still a minor force since the wings aren't optimized for it).

Rather aircraft use elaborate high lift devices such as double slotted flaps and slats, increasing the effective wing area by up to 50%. (Though during take off HLD's are only extended by like 75%, during landing they are more/fully extended).

 

I've for a long time wondered why aircraft in ksp seem to be "engines with wings", with often a TWR of above 1. While the design don't look like fighter craft - so in reality we expect aircraft to work with a maximum TWR of ~0.4. Only conclusion I can come up with is that either the maximum lift coefficient is very low, or the maximum lift-to-drag ratio is way way below what one would expect.

[Decus91]

4 minutes ago, paul23 said:

Just to shed some light on realism:

 

In reality aircraft never use ground effect. - At least while designing. (And even in reality it is still a minor force since the wings aren't optimized for it).

Rather aircraft use elaborate high lift devices such as double slotted flaps and slats, increasing the effective wing area by up to 50%. (Though during take off HLD's are only extended by like 75%, during landing they are more/fully extended).

 

I've for a long time wondered why aircraft in ksp seem to be "engines with wings", with often a TWR of above 1. While the design don't look like fighter craft - so in reality we expect aircraft to work with a maximum TWR of ~0.4. Only conclusion I can come up with is that either the maximum lift coefficient is very low, or the maximum lift-to-drag ratio is way way below what one would expect.

I'm fairly sure the wings just don't produce anything like enough lift and/ or everything is way too heavy (as someone said previously), also flaps don't seem to work at all, and slats don't exist. Add all this together, and well... its still better than stock  My first aircraft are usually retro bi-planes lol.

Edited December 13, 2016 by Decus91

[Hodo]

So I read the last page and that is it.  I am not going to say people are wrong or right, but they know who they are.  

Fact is I have been waiting patiently like some of you for Ferram4 to update this mod.  I dont play KSP without it.  And I have recently been getting the itch again.   But he will release a stable version soon enough.  It just takes time.  

So for those of you out there talking about things you have Googled about, or seen a Youtube documentary about doesnt make you a subject matter expert.   Leave F4 to work in peace and get this code out.

 

Thank you.

[stellargeli]

Easy there cowboy, people are just having a discussion.  I don't think anyone is trying to bother Ferram4.  Do we need a new thread just to discuss aerodynamics?  Wondering if there is one, gonna go look....

Edited December 14, 2016 by stellargeli

[cantab]

17 hours ago, paul23 said:

I've for a long time wondered why aircraft in ksp seem to be "engines with wings", with often a TWR of above 1.

If we start talking about what KSP players actually build, there are quite a lot of factors. To start with, yes the high weight of craft, imposition of a supersonic-optimised airfoil, and lack of sophisticated high-lift devices all conspire to make planes with fast takeoff speeds. Add in that the KSP runway is a bit short, and if you're doing bush flying there's even more desire for a quick takeoff. (And of course if you want a VTOL the lift engines have gotta have TWR above 1!)

But then consider that also few KSP players want to pootle around at 60 m/s in a light aircraft or even 300 m/s in an airliner. We're building SSTOs that hit Mach 4 on jet engines and then fire up rockets to go even faster. Or we're building fast and manoeuvrable fighter jets to pull stunts around the space centre. Or even if we just wanna go to the next continent for a pesky contract, most of us would at least like to be supersonic.

With all that in mind it's no great surprise that we're building lots of planes with lots of engine power and fast takeoff and landing speeds. But it doesn't have to be that way. You can make a plane, whether you're using stock of FAR, that'll get off the ground at about 30 m/s and fly on about a kilonewton of thrust.

[Ser]

26 minutes ago, cantab said:

You can make a plane, whether you're using stock of FAR, that'll get off the ground at about 30 m/s and fly on about a kilonewton of thrust.

How? The lightest of mine was able to rotate at 50-60 m/s with FAR, AJE and stock parts for the rest. Can't say how much TWR it had (it was about 1, as i recall) and it used the earliest of AJE engines.

I hope you're talking about piloted crafts, not mini-sats with wings?

[Akira_R]

41 minutes ago, Ser said:

How? The lightest of mine was able to rotate at 50-60 m/s with FAR, AJE and stock parts for the rest. Can't say how much TWR it had (it was about 1, as i recall) and it used the earliest of AJE engines.

I hope you're talking about piloted crafts, not mini-sats with wings?

I've had lift off speeds between 30-40m/s but I was using KAX, and AirplanesPlus, and they weren't little micro drones, but they had top speeds of like 200m/s which made it so they were only useful thanks to KerbinSides extra runways all over the place, even then it was annoying getting to contract locations. I usually only use mk1 structural parts and clip a couple mk0 fuel tanks into the body for fuel as the mk1 fuel tanks have just obscene amounts of fuel and are so heavy, really need to look into seeing if fuel wings is still a thing... but I'm lazy....

[JayPee]

20 minutes ago, Akira_R said:

really need to look into seeing if fuel wings is still a thing

I think i remember reading somewhere that this was possible with B9 procedural wings but i haven't looked into it

 

because like you, i am lazy.

Edited December 14, 2016 by JayPee
correct verb tense

[ss8913]

3 minutes ago, JayPee said:

I think i remember reading somewhere that this was possible with B9 procedural wings but i haven't looked into it

 

because like you, i am lazy.

Yes b9 procedural wings lets you put fuel in the wings.  works with modular fuel tanks even, so you can put like xenon or hydrazine or chocolate in them even.

[paul23]

1 hour ago, cantab said:

If we start talking about what KSP players actually build, there are quite a lot of factors. To start with, yes the high weight of craft, imposition of a supersonic-optimised airfoil, and lack of sophisticated high-lift devices all conspire to make planes with fast takeoff speeds. Add in that the KSP runway is a bit short, and if you're doing bush flying there's even more desire for a quick takeoff. (And of course if you want a VTOL the lift engines have gotta have TWR above 1!)

But then consider that also few KSP players want to pootle around at 60 m/s in a light aircraft or even 300 m/s in an airliner. We're building SSTOs that hit Mach 4 on jet engines and then fire up rockets to go even faster. Or we're building fast and manoeuvrable fighter jets to pull stunts around the space centre. Or even if we just wanna go to the next continent for a pesky contract, most of us would at least like to be supersonic.

With all that in mind it's no great surprise that we're building lots of planes with lots of engine power and fast takeoff and landing speeds. But it doesn't have to be that way. You can make a plane, whether you're using stock of FAR, that'll get off the ground at about 30 m/s and fly on about a kilonewton of thrust.

Well I wish to create something like the concorde: a supersonic craft (post mach 2) - but still a TWR of about 0.372. Emulating HLDs with decouplers and reducing landing distance with parachutes.

 

Also notice I talk about TWR: thrust to weight ratio: with heavier command structures etc the same TWR just means everything becomes larger and thus the weight of parts is of little influence?

 

Maybe indeed the small runway is the biggest problem? Since the concorde has a lift off speed of 77 m/s

Edited December 14, 2016 by paul23

[Gordon Fecyk]

2 hours ago, cantab said:

You can make a plane, whether you're using stock of FAR, that'll get off the ground at about 30 m/s and fly on about a kilonewton of thrust.

Like this one:

Spoiler

 

This was Veeltch's idea, cloning a MiG-9 to re-learn how to design and fly with FAR.

--

[Nnimrod]

You know you could just make a mod that changes the mass of various aero parts to realistic values are see how far feels then. 95% of the work would just be researching weights. I worked in a warehouse once that held mostly aluminum body and wing pieces for small planes, and they're surprisingly light.

[tetryds]

I just think that this whole design and aircraft discussion should move over to http://forum.kerbalspaceprogram.com/threads/121176-Official-FAR-Craft-Repository

Mainly because that has nothing to do with the purpose of this thread, ground effect was commented on and that's as far as it goes regarding the mod itself, how to work around it and other things like that have nothing to do with it.

It also adds a lot of cluster in here.

[Sol Invictus]

@tetryds What else would be this thread for then? Only bug reports and release announcements? Isn't there already github for that? Science of aerodynamics is a heart of FAR, and discussing it here honours ferram's work better than anything else. Not only that, it can introduce new players to new exciting knowledge and potentially help make FAR even better. It's not like people started discussing science here only yesterday, this thread always was a welcoming place for this sort of thing. Also, it's silly complaining about adding cluster when there's already 519 pages of content here. I rather embrace it and appreciate every single post, as they are all created out of love to this amazing mod.

[cantab]

3 hours ago, Ser said:

How? The lightest of mine was able to rotate at 50-60 m/s with FAR, AJE and stock parts for the rest. Can't say how much TWR it had (it was about 1, as i recall) and it used the earliest of AJE engines.

I hope you're talking about piloted crafts, not mini-sats with wings?

I acknowledge it's from really old FAR, but example: https://flic.kr/p/qykBU6

My thinking when designing that (actually I first designed it for a mod electric prop then did an ion conversion) was that anything that's not wing or engine isn't helping me fly, and therefore I should minimise it. I don't recall the top speed or service ceiling, but it flew nicely.

As for what belongs in what thread, well I don't think ferram has clearly stated in this thread that it's not for wider discussion about the effects of FAR and how to design for it. In any case the majority of players who encounter unexpected behaviour with FAR will not know whether such unexpected behaviour is correct or is a bug; aerodynamics is complicated. Meanwhile if you want "Official FAR Craft Repository" to be a place for that kind of discussion then my view is that thread has both a misleading title and is in the wrong forum.

[Tricky14]

I really need to stop myself from checking in on this thread every day for an update. Is there something to the effect of a mailing list for FAR? Sorry using a quaint sort of phrase for it, but I think you get what I mean. Would like the notification of an update to be automated, if possible.

[JayPee]

@Tricky14preferences are right up here:

 

[paul23]

2 hours ago, tetryds said:

I just think that this whole design and aircraft discussion should move over to http://forum.kerbalspaceprogram.com/threads/121176-Official-FAR-Craft-Repository

Mainly because that has nothing to do with the purpose of this thread, ground effect was commented on and that's as far as it goes regarding the mod itself, how to work around it and other things like that have nothing to do with it.

It also adds a lot of cluster in here.

I am just wondering what the cl-alpha and cl-cd graphs of the wings FAR uses are 

[Drew Kerman]

5 hours ago, paul23 said:

I am just wondering what the cl-alpha and cl-cd graphs of the wings FAR uses are 

try this, a bit dated but still valid I believe

 

[Maeyanie]

7 hours ago, Tricky14 said:

I really need to stop myself from checking in on this thread every day for an update. Is there something to the effect of a mailing list for FAR? Sorry using a quaint sort of phrase for it, but I think you get what I mean. Would like the notification of an update to be automated, if possible.

SpaceDock has a feature which does exactly what you want. Go to http://spacedock.info/mod/151/Ferram Aerospace Research and log in, and there should be a "Follow" button right beside "Download" which will give you notifications when there's an update.

[Tricky14]

3 hours ago, Maeyanie said:

SpaceDock has a feature which does exactly what you want. Go to http://spacedock.info/mod/151/Ferram Aerospace Research and log in, and there should be a "Follow" button right beside "Download" which will give you notifications when there's an update.

Exactly what I needed. Thanks for the tip, Maeyanie.