[0.90] Stock Drag Fix - Mar 19, 2015 (BETA UPDATE)

[Ignath]

I'll set up the netkan file for you if you want. I think that the github link will be enough for ckan to even automatically index future updates.

Yep, that's the beauty of CKAN...any time you update, it will eventually (think Ippo said the indexing runs ~1/hour) be indexed and the update will be made available to CKAN users.

[Starwaster]

I'll set up the netkan file for you if you want. I think that the github link will be enough for ckan to even automatically index future updates.

Edit:

This netkan file works just fine:

{

"spec_version" : 1,

"identifier" : "StockDragFix",

"$kref" : "#/ckan/github/Starwaster/StockDragFix",

"name" : "Stock Drag Fix",

"abstract" : "Fixes aerodynamic issues without breaking compatibility",

"license" : "CC-BY-SA-4.0",

"ksp_version" : "0.90"

}

If it is ok with the author, I can even take care of the pull request to netkan's repo.

I have no objections, but I was just looking at the CKAN wiki and it seems like having a .version file would be better than specifying the ksp_version? I still have to look into that part as I don't know what format the .version file needs to be.

[pacbard]

Done: https://github.com/KSP-CKAN/NetKAN/pull/189

[Starwaster]

Added a version file to the git

[Whirligig Girl]

Does this have any special treatment for nosecones or fairings?

[Starwaster]

Does this have any special treatment for nosecones or fairings?

It does not

What needs to happen there is that I actually need to impose drag penalties for uncapped tanks (or any open node) the way FAR does.

Because as it stands right now, the amount of drag imposed for a typical rocket stack with no nose cone is about on par with a rocket stack in FAR that has nose cones.

Literally, if you take a rocket with no nose cone in SDF then measure the drag on a launch straight up then quit KSP and replace SDF with FAR, the same rocket will have (appropriately) more drag. Cap that stack with a nose cone and run it again in FAR and your drag losses are going to be within a few 10s of m/s worth of extra drag.

Very large diameter parts are probably getting more drag in SDF than they should but I'm not actually sure about that. I have to sit down with some 5m and 10m parts and really give them a good going over. But my gut tells me that they're probably getting more drag than they should be.

Edit: On the subject of fairings, I have to write something up to detect if parts are enclosed in fairings. I don't want to do it the way FAR is doing it because parts very near the fairing wall tend to be missed. The way Procedural Fairings does it is better and I just need to take the time to sit down and write up code. (basically, find every part attached to the top node of the fairing base and call that the payload. If the fairings are attached to the base, the payload is marked as shielded)

Although not asked, on the subject of cargo bays, it gets much easier. KSP 0.25 introduced a cargo bay module that checks for enclosed parts and exempts them from drag. That's easy enough to add to any animated cargo bay. Some other modders expressed concerns that the system would unbalance stock KSP but I consider those concerns to be grossly overblown.

Edited December 16, 2014 by Starwaster

[Galane]

Good to see lots of mods getting .90 updates.

[Virtualgenius]

I like this drag fix much better than FAR or NEAR they are to complex to use this one is better the little tweaks you want to make sound really good

Edited December 19, 2014 by Virtualgenius

[Starwaster]

I like this drag fix much better than FAR or NEAR they are to complex to use this one is better

Plus it works with stock SAS and MechJeb because it doesn't replace control surfaces that both of them already know how to interpret

[KerBlam]

Thanks!

I'm running .90 in linux 64, and I like this much better than NEAR or FAR... I'm here to play a game, not tear my hair out. This feels much nicer than stock.

[Starwaster]

Thanks!

I'm running .90 in linux 64, and I like this much better than NEAR or FAR... I'm here to play a game, not tear my hair out. This feels much nicer than stock.

Glad I was able to help you stave off premature balding!

[Galane]

I'm going to have to uninstall SDF because the current dev version of MechJeb cannot land anything on Kerbin with it. Not even this http://pastebin.com/wLrAUttX which it has been pretty much perfect with for as long as I've been using MechJeb. It doesn't have an AR202 on it due to using module manager for MechJeb integration. I built that lander in .21, it's been to Mun a few times and landed on Kerbin many times, manned and unmanned.

It does the deorbit burn, too much. Then it has to do a correction burn, again it does way too much. It keeps flipping the ship back and forth, constantly overcorrecting and it misses the landing target. Doesn't matter if it has RCS on or not.

In .25 with previous versions of SDF and MechJeb it would only burn too much on the deorbit burn, then it'd correct - but not too much - and settle down to landing.

[Starwaster]

I'm going to have to uninstall SDF because the current dev version of MechJeb cannot land anything on Kerbin with it. Not even this http://pastebin.com/wLrAUttX which it has been pretty much perfect with for as long as I've been using MechJeb. It doesn't have an AR202 on it due to using module manager for MechJeb integration. I built that lander in .21, it's been to Mun a few times and landed on Kerbin many times, manned and unmanned.

It does the deorbit burn, too much. Then it has to do a correction burn, again it does way too much. It keeps flipping the ship back and forth, constantly overcorrecting and it misses the landing target. Doesn't matter if it has RCS on or not.

In .25 with previous versions of SDF and MechJeb it would only burn too much on the deorbit burn, then it'd correct - but not too much - and settle down to landing.

What do you expect me to do about it?

Why are you posting about MechJeb problems here?

[Galane]

Perhaps discuss with Sarbian ways to make the two play nicely together?

[oktav]

Perhaps discuss with Sarbian ways to make the two play nicely together?

There is no atmosphere in while doing the reentry manouver, if mechjeb is using drag to calculate how much thrust to do then something is off in mechjeb...

I started trying the mod instead of FAR as I was playing in Hard mode, and couldn't afford to try 20 planes...

It's very interesting but in fact it misses just a few things like nosecones, fairings and I also liked the display of the drag force in FAR.

I will see if I'll find the time to look into the API how to do those things, but I doubt

[Guest]

Perhaps discuss with Sarbian ways to make the two play nicely together?

There must be something else gumming up the works. All my Kerbin re-entries, either powered or ballistic, have been less than 500m off target.

[Starwaster]

Perhaps discuss with Sarbian ways to make the two play nicely together?

What you're not comprehending is that SDF works by adjusting stock drag parameters. MechJeb already knows how much drag the vehicle will undergo because it's the same properties that MechJeb was using before and it's still stock drag.

There is no atmosphere in while doing the reentry manouver, if mechjeb is using drag to calculate how much thrust to do then something is off in mechjeb...

I started trying the mod instead of FAR as I was playing in Hard mode, and couldn't afford to try 20 planes...

It's very interesting but in fact it misses just a few things like nosecones, fairings and I also liked the display of the drag force in FAR.

I will see if I'll find the time to look into the API how to do those things, but I doubt

If you're using MechJeb, it already can display drag force. If you don't already have a MJ window that says 'Atmosphere Info' then use the custom window editor (built into MJ) to create one.

[oktav]

If you're using MechJeb, it already can display drag force. If you don't already have a MJ window that says 'Atmosphere Info' then use the custom window editor (built into MJ) to create one.

thanks, but no thanks. I don't want to use MechJeb, i prefer to play the game

[Galane]

Here's a fresh output_log http://partsbyemc.com/pub/output_log.zip

I deleted Stock Drag Fix and Landing Guidance had no problem landing my Stock Lander 1. One deorbit burn followed by one small correction then an uneventful cruise down to the landing burn.

So I deleted the log, put SDF back and the above log is the result. At the end it did a major change in orbit inclination then turned around and made a feeble effort to correct it.

The only difference between the two runs was the presence or absence of SDF so somehow SDF is mucking up some information MechJeb uses for calculating how to land with an atmosphere.

[Starwaster]

Here's a fresh output_log http://partsbyemc.com/pub/output_log.zip

I deleted Stock Drag Fix and Landing Guidance had no problem landing my Stock Lander 1. One deorbit burn followed by one small correction then an uneventful cruise down to the landing burn.

So I deleted the log, put SDF back and the above log is the result. At the end it did a major change in orbit inclination then turned around and made a feeble effort to correct it.

The only difference between the two runs was the presence or absence of SDF so somehow SDF is mucking up some information MechJeb uses for calculating how to land with an atmosphere.

Sorry but nothing in that log file is of any use to me. Other than SDF being loaded and a few debug messages indicating that it is doing its job, there is nothing in that log about SDF. It does have errors from other mods however, including MechJeb.

Now then, did you also happen to turn on the "show landing prediction" feature when trying to land? And watching in map view while it does this?

Because, if you do, you will see its own landing predictor move past your selected landing site. And then turn around to course correct its previous burn? The predictor is moving past the target and yet it continues to perform its burn while the marker moves past.

That's not an SDF issue and coincidence doesn't equal causality. And the log file does not support what you're saying.

[chrisl]

I've tried FAR and found it way too complicated. And I've tried NEAR but don't really like that it seems to reduce drag by 95% which makes it possible to get into orbit with practically nothing but your initial research. So far I like what I'm seeing from SDF.

EDIT: It's too bad you can't setup SDF so that fairings and cargo bays could actually "block" what's inside them from the effects of drag.

Edited January 10, 2015 by chrisl

[andruszkow]

I've tried FAR and found it way too complicated. And I've tried NEAR but don't really like that it seems to reduce drag by 95% which makes it possible to get into orbit with practically nothing but your initial research. So far I like what I'm seeing from SDF.

EDIT: It's too bad you can't setup SDF so that fairings and cargo bays could actually "block" what's inside them from the effects of drag.

This!

Even with the stock aero model rework for the future release coming, is it possible to implement this?

[Starwaster]

This!

Even with the stock aero model rework for the future release coming, is it possible to implement this?

Possible, yes. Can't say when it would happen

[andruszkow]

Question: I've read through the posts, and no real thing has been done to lift ratings. However, I guess this does affect the effective lift of planes? Even though the total mass of a plane is the same, there's less drag, because fuel is out of the equation. How does it really affect the dynamics of lift-surface vessels?

[Starwaster]

Question: I've read through the posts, and no real thing has been done to lift ratings. However, I guess this does affect the effective lift of planes? Even though the total mass of a plane is the same, there's less drag, because fuel is out of the equation. How does it really affect the dynamics of lift-surface vessels?

It doesn't affect lift ratings at all.

That's something that could be done if there's sufficient need for it.

I don't fly planes that much and never really looked at the lift system in stock so I didn't give it much thought.