[0.90]NEAR: A Simpler Aerodynamics Model v1.3.1 12/16/14

[Tigermisu]

pull request?

[DaMichel]

Good luck with this.

Btw. doesn't a pull request require you to upload your stuff first, which is unfortunately prohibited by DYJ's "license"?

Edit: to answer the question (sorry).

https://confluence.atlassian.com/display/BITBUCKET/Work+with+pull+requests

Basically you fork the original code. Make your modifications and send a request - the pull request - to the original author to incorporate these changes. There is special support for this from the hoster bitbucket or github, which makes it quite easy to do so.

Edited August 30, 2014 by DaMichel

[Tigermisu]

The PWings dev said he's already making it compatible and fixing some bugs in the way, so I will just contact the Firespitter dev.

[chrisb2e9]

Sorry for not reading through pages of this thread, as maybe this is a known issue.

I was landing a plane. Came in too fast, bounced my first touchdown. But when I did, I noticed that my speed had increased by about 70m/s(after I bounced). With the engines cut, I could pull up, push forwards, and repeat over and over again to give my airplane constant acceleration.

I do have some mods,

Mechjeb

KWrocketry

Space plane plus

Station Science

Fire spitter

Quantum struts

And lastly Taverio's Pizza and Aerospace

Is this just a mod issue? Or a known bug, or something new?

Edit:

And just to add something else. I'm taking a break from visiting other planets and dropping home made bombs on the KSC. Specifically Goo containers, for... science...

I dropped 10 and watched several fall, gain altitude, fall, fly around. and finally hit the ground. Just random patterns from what I could tell. Is this normal behavior in this mod?

Thanks!

Edited August 30, 2014 by chrisb2e9

[ferram4]

This is not a NEAR issue.

This is an issue with parts that do not have configs to work with NEAR, and thus you are running into the stock infiniglide issue. Check with the mod control surfaces that you are using to make sure that they are not only compatible with FAR, but that they also implement their compatibility if NEAR is present.

[chrisb2e9]

Ah, thank you. I couldn't see this being the way that it is supposed to work.

And thanks for the quick reply!

[WaveFunctionP]

I just installed near. I feel really dumb, but I've done a google search and thread search, but on the control surface there are many options.

Anywho, my question is what are those two other options, or rather, how does one use the flaps or spoilers. Do they need to bound to an action group or do they behave intelligently?

A bit of polish type feedback:

The toggles for control surfaces all default to false (on SP+ parts atleast), it is a bit strange that the default behavior is not behave at all.

The tooltip for flaps and spoilers could use some tweaking. Flaps should just say Flaps like it does for roll/pitch/yaw. I do not think that you need to be as verbose about what the toggle does. "Use as Flaps" is not any more informative than just "Flaps" either you know what that means or not.

The spoiler setting is cutoff. It just says "Use as spo.." I had to look in the action menu to find out what it does. It also has the same "polish issue" as flaps does.

I think that a small toolbar/window might be useful (nothing fancy) as the game does not tell you what exactly the settings do. If you need to use action groups for any of these settings, or if there are any keybinds, this would be a good place to inform the player, I think. At the very least a bit more information on the forum post or readme.txt in the download.

I am glad that you've developed a simpler model than FAR for more "casual" players. I look forward to play with this more.

[Master Tao]

Anywho, my question is what are those two other options, or rather, how does one use the flaps or spoilers. Do they need to bound to an action group or do they behave intelligently?

For flaps, it's usually best to set them to action groups, but you can also raise/lower them in flight from the context menu. They'll move in symmetric pairs.

By default, spoilers are bound to the Brakes action group.

Note that you can't set control surfaces to both Flaps and Spoilers. If you try, they'll only work as flaps.

The toggles for control surfaces all default to false (on SP+ parts atleast), it is a bit strange that the default behavior is not behave at all.

They actually default to on, but FAR and NEAR switch the button state to depressed (dark dark) for on and raised (light green) for off. Definitely a little confusing coming from stock.

[noobz]

Hello friends.

I installed NEAR for the first time last week, along with the new B9 pack - and i really like it

But sometimes aircraft construction ends up in a guessing game: more wings? more control surfaces? is the COL in the correct position? or not?

So i decided to replace NEAR with FAR and use the built in analysis tool for construction and then switch back to NEAR.

But things didn't quite work out, because planes that were stable in FAR are totally useless in NEAR. I also noticed that NEAR patches less parts (through module manager) than FAR.

Is that a bug or a feature?

[JewelShisen]

Do you have to have FAR installed as well to make this work or is it a stand alone plugin?

[SirJodelstein]

This is a picture of a test - and i don't understand the behaviour here: The RGU (mass modded to 500, COG is quite exactly within the RGU, no SAS activated) is falling vertically. This is the stable pose it goes into after beeing sun up before release.

Well, i thought it should fall flat-end first, the shape looks quite similar to an apollo/MSL capsule right? I guess it must have something to do with body lift? While i enjoy trying to figure stuff like this out, some pointers with regard to aerodynamic stable reentry design (preferrably without wings) would be appreciated.

[ferram4]

@WavefunctionP: Making the tweakables clearer is on the to-do list, but that will come in FAR before NEAR, probably.

@noobz: Planes that are stable in FAR, but not in NEAR are running into the changes NEAR makes that greatly simplifies the aerodynamics for players at the cost of making them very wrong. In particular, anything that takes heavy advantage of wing interactions will not work well with NEAR, simply because NEAR pretends that wing interactions don't exist.

@JewelShisen: No, you don't need FAR; why would I make you go to two separate threads to install NEAR? In fact, having both at the same time is a damn good way to have lots of problems.

@SirJodelstein: That looks a lot like the CoM isn't low enough / the "heat shield" part you're using isn't flat enough for that purpose.

Making a stable reentry vehicle is the same as making anything aerodynamically stable: aerodynamic center (or Center of Lift if you insist on that) behind the CoM. That's it. So make the thing relatively cone-shaped, with as much mass near the blunt end as possible. It should be wider than it is tall, ideally.

[SirJodelstein]

@SirJodelstein: That looks a lot like the CoM isn't low enough / the "heat shield" part you're using isn't flat enough for that purpose. Making a stable reentry vehicle is the same as making anything aerodynamically stable: aerodynamic center (or Center of Lift if you insist on that) behind the CoM. That's it. So make the thing relatively cone-shaped, with as much mass near the blunt end as possible. It should be wider than it is tall, ideally.

Well, still having a hard time wrapping my head around these new concepts (very much enjoying the process though :-))

Here is the next test. This time with a heavy and extra-flat heatshield from Deadly Reentry. Still the same. However, if i remove the heatshield, suddenly RGU-first downwards is the stable pose.

Wider than tall also doesnt help completely (again falling vertically here).

Or is this because the velocity is not high enough? do these shapes become stable in the upper atmosphere with orbital speeds? How do other users build their science return capsules with this mod? Is this behaviour different in FAR? If so, maybe i should consider using that?

Edited September 2, 2014 by SirJodelstein

[SirJodelstein]

Yes! Its all about the speed! The shapes are self-stabilizing at high velocities and begin to destabilize/change pose at low altitudes and speeds. Wow.

[BadManiac]

* Downloads and installs NEAR

* Builds bog standard satellite launch rocket with KW fairings and stabilizing fins

* Launches straight up no problem

* Begins gravity turn, rocket completely flips out of control and won't stop spinning

* Uninstalls and deletes NEAR

First impressions and all that, you guys can keep your "realistic" aerodynamics, I'll stick with the ones that allow me to point a rocket at space and go...

And before anyone asks, here's the rocket. pretty standard stuff, nothing off balance, all three markers are in line.

Edited September 3, 2014 by BadManiac
added screenshot

[forsaken1111]

* Downloads and installs NEAR

* Builds bog standard satellite launch rocket with KW fairings and stabilizing fins

* Launches straight up no problem

* Begins gravity turn, rocket completely flips out of control and won't stop spinning

* Uninstalls and deletes NEAR

First impressions and all that, you guys can keep your "realistic" aerodynamics, I'll stick with the ones that allow me to point a rocket at space and go...

This has pretty much been my experience as well, every time I've tried to use it.

[Harry Rhodan]

* Begins gravity turn, rocket completely flips out of control and won't stop spinning

The answer is actually in the FAQ for FAR: turn slowly and steady right after launch. If you try to suddenly turn 45° like in vanilla, you give the air pressure a big leaver that'll just flip you over. Especially because you are accelerating way faster due to the lowered drag when using fairings. Try to keep your velocity near the terminal velocity and turn slowly from the beginning and your launch will be easier and more economical than without NEAR.

[Arron Rift]

Hey, just wanted to say I downloaded you mod last night and it's actually a lot of fun! I was worried it'd make plane designing a pain and tear them apart, but I think it actually is making them fly faster! Is that possible or is it my imagination?

[Harry Rhodan]

but I think it actually is making them fly faster!

In vanilla every part produces a flat amount of drag even if they are shielded behind or inside other parts. This means putting on fairings drags you down even more. With NEAR/FAR the shape of your rocket counts and fairings reduce the drag significantly. Yesterday I got into orbit with a dv of about 3200m/s and had the thrust down to around 50% for the vertical ascent.

[skbernard]

@BadManiac , @forsaken1111 - the problem, like Harry said, is that you're trying to bluntly and rapidly angle your rocket - with NEAR or FAR you need to gently slice through the air, instead of smacking it with a flat baseball bat

in vanilla KSP the game simulates a flat bat flying through the air, smacking the air all the way up to space, but instead of flipping your ship, its makes your rockets work harder and burn more fuel - with proper drag you're actually cutting through the air (if you make your ship correctly and point it correctly) and making it easier on your engines, leaving you up in space in a stable orbit while expending less dV (sometimes over a 1,000dV saved)

[NWDogg]

* Downloads and installs NEAR

* Builds bog standard satellite launch rocket with KW fairings and stabilizing fins

* Launches straight up no problem

* Begins gravity turn, rocket completely flips out of control and won't stop spinning

* Uninstalls and deletes NEAR

First impressions and all that, you guys can keep your "realistic" aerodynamics, I'll stick with the ones that allow me to point a rocket at space and go...

Nothing wrong with going back to stock aerodynamics if you don't like the real stuff. I was turned off by it at first as well. This is why I seriously doubt Squad will ever implement that into the stock game, and it's a great thing that we have ferram in the community.

Someone mentioned terminal velocity, and I've been meaning to ask this. Now, this might sound like a stupid question, but with FAR/NEAR, is terminal velocity the same as stock? As in, 157 m/s at 5000 meters, 260 at 10000, etc.., or is there a different terminal velocity table that I've yet to find? It seems to me like it's different, just based on assumption, but I'm not a math whiz so I need to ask.

Also, is there a better KIDS setting to use with NEAR, rather than the FAR-to-Stock KSP-Adjusted? I know NEAR further reduces to-orbit deltaV requirements from FAR, so would a lower number in KIDS work better to balance things out, or is it close enough to not make a difference?

[Arron Rift]

Nothing wrong with going back to stock aerodynamics if you don't like the real stuff. I was turned off by it at first as well. This is why I seriously doubt Squad will ever implement that into the stock game, and it's a great thing that we have ferram in the community.

Someone mentioned terminal velocity, and I've been meaning to ask this. Now, this might sound like a stupid question, but with FAR/NEAR, is terminal velocity the same as stock? As in, 157 m/s at 5000 meters, 260 at 10000, etc.., or is there a different terminal velocity table that I've yet to find? It seems to me like it's different, just based on assumption, but I'm not a math whiz so I need to ask.

Also, is there a better KIDS setting to use with NEAR, rather than the FAR-to-Stock KSP-Adjusted? I know NEAR further reduces to-orbit deltaV requirements from FAR, so would a lower number in KIDS work better to balance things out, or is it close enough to not make a difference?

I second this question. Also, I've found KER's terminal velocity readout to be very helpful back with stock, but how accurate is that with NEAR?

[Arron Rift]

* Downloads and installs NEAR

* Builds bog standard satellite launch rocket with KW fairings and stabilizing fins

* Launches straight up no problem

* Begins gravity turn, rocket completely flips out of control and won't stop spinning

* Uninstalls and deletes NEAR

First impressions and all that, you guys can keep your "realistic" aerodynamics, I'll stick with the ones that allow me to point a rocket at space and go...

And before anyone asks, here's the rocket. pretty standard stuff, nothing off balance, all three markers are in line.

http://i.imgur.com/RkuetVm.png

Dude, just try moving the wings up to the center of mass. I had that problem when I was using stock, as the moment a rocket with fins at the bottom turns sideways it has a chance to turn into a lawn-dart

[ferram4]

@BadManiac & forsaken1111: Yeah, and that behavior is pretty much what you see any time a real life rocket goes out of control and reaches a high angle of attack. In particular, that rocket you posted (with the gigantic fairing) will become highly unstable if you reach an angle of attack high enough to make the size of the fairing matter. Also, what's your TWR? Very high TWRs encourage rockets to lose control and become unstable.

I'm curious though, considering that ascent profiles are heavily affected by aerodynamic forces, did you not think that changing aerodynamics would require changes to your flight profile?

@NWDogg & Arron Rift: Ignore terminal velocity. You will not reach it and will have control difficulties if you get close to it. You're making the same mistakes that BadManiac and forsaken1111 seem to be making, but at a later stage.

[Dre4dW0rm]

Is it intended bahaviour that TurboJet Engine is 110 thrust and basic jet engine is 150 ? I can't get any plane with Turbo Jet off the ground with NEAR. The ratio of mass and consumption vs thrust is ridiculous.