[1.12.3] Kerbal Wind Tunnel 1.3.1.1

[kerbalxploder]

This mod is really cool, I owe some plane designs to this mod. However, I recently used this mod on one of my stratolaunchers and cpu utilization shot up to 100 until KSP just froze. I have no idea what happened here, but if someone could assist me here. 

 

I will post a pic of my stratolauncher and log file later. 

[Booots]

13 minutes ago, kerbalxploder said:

This mod is really cool, I owe some plane designs to this mod. However, I recently used this mod on one of my stratolaunchers and cpu utilization shot up to 100 until KSP just froze. I have no idea what happened here, but if someone could assist me here. 

 

I will post a pic of my stratolauncher and log file later. 

CPU utilization going to 100% is normal - it’s doing a lot of math. The freezing is bizarre but I’d have to see a log file and/or the craft file to reproduce it. 

[kerbalxploder]

On 1/7/2021 at 10:21 PM, Booots said:

CPU utilization going to 100% is normal - it’s doing a lot of math. The freezing is bizarre but I’d have to see a log file and/or the craft file to reproduce it. 

 

EDIT: The problem was the mouse over fairing thing, I had that on and it looks like that was what caused this

I use an i3 9100f and a 1650 super with 16gb system ram. Here are some screenshots, craft files and the log:

https://drive.google.com/file/d/1A938fLw5gnbIL9AqrnY2yJn5Ri-5PWZs/view?usp=sharing (ksp.log)

https://drive.google.com/drive/folders/17s-YmUUTBpo8jWZH_j02X47Sv5g7yFQI?usp=sharing (Craft file)

 

Edited January 11, 2021 by kerbalxploder

[WelshSteW]

Hi,

If I built a really basic rocket in the VAB, like just a Flea with a Stayputnik on top, could this mod tell me how high the thing will reach, assuming a straight upward trajectory, based on how much fuel I put into it?

And then, could it tell me how high I'd go, and how far along horizontally, if I changed the trajectory angle?

Edited January 12, 2021 by WelshSteW

[Booots]

2 hours ago, WelshSteW said:

If I built a really basic rocket in the VAB, like just a Flea with a Stayputnik on top, could this mod tell me how high the thing will reach, assuming a straight upward trajectory, based on how much fuel I put into it?

And then, could it tell me how high I'd go, and how far along horizontally, if I changed the trajectory angle?

Unfortunately no, this mod does not account for fuel burn and neither does it calculate burn time. Fortunately, it’s relatively easy to calculate burn time from Isp (you will have to make an assumption about whether to use vacuum or sea level). From that, the rocker equation, and some simple physics it’s pretty easy to calculate how high it’ll go. (I could link you the equations if you like but they’re all on Wikipedia and I encourage self-learning because it’s retained better)

Now, those equations ignore drag and that’s one area where this mod can help. The ‘Velocity Curves’ tab will let you get your rocket’s drag coefficient by Mach number. Multiply that by the dynamic pressure and wing area (the sum of all your fins) and you’ll have everything you need to predict how high your rocket will actually go!

[kerbalxploder]

Is there a way you could add a feature to calculate the most efficient atmospheric ascent profile for a rocket? I think this will make the mod vastly popular

[fuzzypeaches]

Hey, really enjoying the mod so far. I find I spend more time in the SPH tweaking than flying. Every once in a while though, I run into a CTD with similar log messages to this:
 

Quote

[LOG 17:15:22.711] ******* Log Initiated for Kerbal Space Program - 1.11.0.3045 (WindowsPlayer x64) en-us *******
Kerbal Space Program - 1.11.0.3045 (WindowsPlayer x64) en-us

OS: Windows 10  (10.0.0) 64bit
CPU: Intel(R) Core(TM) i5-6600K CPU @ 3.50GHz (4)
RAM: 16296
GPU: NVIDIA GeForce GTX 1070 (8088MB)
SM: 50 (Direct3D 11.0 [level 11.1])
RT Formats: ARGB32, Depth, ARGBHalf, Shadowmap, RGB565, ARGB4444, ARGB1555, Default, ARGB2101010, DefaultHDR, ARGB64, ARGBFloat, RGFloat, RGHalf, RFloat, RHalf, R8, ARGBInt, RGInt, RInt, BGRA32, RGB111110Float, RG32, RGBAUShort, RG16, BGRA10101010_XR, BGR101010_XR, R16

........

[ERR 17:53:20.359] Wind tunnel task faulted

[EXC 17:53:20.360] IndexOutOfRangeException: Index was outside the bounds of the array.
    KerbalWindTunnel.Extensions.Linq2+<GetTaxicabNeighbors>d__11`1[T].MoveNext () (at <5f79df7056694b3294a25449ef7f5fea>:0)
    KerbalWindTunnel.DataGenerators.EnvelopeLine.GetOptimalPath (KerbalWindTunnel.DataGenerators.EnvelopeSurf+Conditions conditions, System.Single exitSpeed, System.Single exitAlt, System.Single initialSpeed, System.Single initialAlt, KerbalWindTunnel.DataGenerators.EnvelopeLine+CostIncreaseFunction costIncreaseFunc, System.Predicate`1[T] neighborPredicate, System.Single[,] predicateData, KerbalWindTunnel.DataGenerators.EnvelopeLine+CostIncreaseFunction timeFunc, System.Threading.CancellationToken cancellationToken) (at <5f79df7056694b3294a25449ef7f5fea>:0)
    KerbalWindTunnel.DataGenerators.EnvelopeLine+<>c__DisplayClass1_0.<ProcessOptimalLine>b__0 () (at <5f79df7056694b3294a25449ef7f5fea>:0)
    System.Threading.Tasks.Task`1[TResult].InnerInvoke () (at <ad04dee02e7e4a85a1299c7ee81c79f6>:0)
    System.Threading.Tasks.Task.Execute () (at <ad04dee02e7e4a85a1299c7ee81c79f6>:0)
    Rethrow as AggregateException: One or more errors occurred.
    UnityEngine.DebugLogHandler:LogException(Exception, Object)
    ModuleManager.UnityLogHandle.InterceptLogHandler:LogException(Exception, Object)
    UnityEngine.Debug:LogException(Exception)
    KerbalWindTunnel.DataGenerators.<ProcessOptimalLine>d__1:MoveNext()
    UnityEngine.SetupCoroutine:InvokeMoveNext(IEnumerator, IntPtr)

I'm admittedly not familiar with exactly how the mod is doing things under the hood, but I think it's running into an issue where it can't find a path to the exitAlt or exitSpeed. I've tried disabling drawing of the envelope but that doesn't seem to help and it's intermittent. Any idea if there's anything I can do to make it a bit more stable? Like close the mod window then make tweaks, then re-open?

[Booots]

On 2/12/2021 at 1:28 PM, kerbalxploder said:

Is there a way you could add a feature to calculate the most efficient atmospheric ascent profile for a rocket? I think this will make the mod vastly popular

I've considered making that as a separate mod, but the problem of optimizing atmospheric ascent profiles for multistage launch vehicles is beyond me. From the research I've done, that seems to be at the cutting edge of academic papers (though I'm sure industry has some lovely and complicated code for it). Like, if I could make it work for KSP, I could publish a journal article about the algorithm. Tempting for the cred, but no... Sorry. I'll do some more reading on the current state of research and if I come across something I can just adapt for KSP instead of developing from scratch I'll reconsider.

On 2/26/2021 at 5:11 PM, fuzzypeaches said:

Hey, really enjoying the mod so far. I find I spend more time in the SPH tweaking than flying. Every once in a while though, I run into a CTD with similar log messages to this:
 

I'm admittedly not familiar with exactly how the mod is doing things under the hood, but I think it's running into an issue where it can't find a path to the exitAlt or exitSpeed. I've tried disabling drawing of the envelope but that doesn't seem to help and it's intermittent. Any idea if there's anything I can do to make it a bit more stable? Like close the mod window then make tweaks, then re-open?

Thanks for the bug report! I've seen that error too, but I can't figure out how it's going out of bounds. In theory, though, the "Wind tunnel task faulted" message means that it's failed gracefully and shouldn't CTD but this mod is doing background work that Unity never expected so who knows... I'll look into that error and see if fixing it prevents CTDs.

[Mata]

fantastic mod, just really wish it worked with FAR, it'd be perfect then.

[ttikkoo]

Would anyone be able to provide me with some pointers on how to go about using the information provided by this wonderful mod? As an enthusiastic amateur at aircraft building in KSP, I am certain this data will help me understand where I'm going wrong if I know how to use it.

I'm not looking for any detailed guides, just maybe a couple of tips on which charts are the most important things to look at so I can do my own research on those. At the moment, I just feel bombarded by charts that I don't quite understand. Any help would be appreciated, thank you.

[Linkageless]

On 5/20/2021 at 2:40 PM, ttikkoo said:

Would anyone be able to provide me with some pointers on how to go about using the information provided by this wonderful mod?

Hi @ttikkoo,

I'm still getting to grips with all that this mod can offer, and can't be sure my interpretation of any of it is all that great.  The best guide I know is from the start of this thread, and have worked stuff out from there.

An obvious example is the Flight Envelope > Excess Thrust, which shows you how much extra thrust you have available over what is needed for steady, level flight.  From @Booots's opening example, you can see the area in red in the middle of the graph is the best combination of speed and altitude for excess thrust, meaning the most acceleration is available, or alternatively I suppose they would be the most economical speed+altitudes to cruise at.

That example specifically indicates altitude 10088m (vertical scale) at speed 762m/s (horizontal scale) should allow you 539kN of thrust spare for accelerating.  If you were at the same altitude (10km) but already going 1450m/s, you'd struggle to find much excess thrust, so wouldn't be able to accelerate much more.  You could get just a little more speed if you climbed to 12km.   If you were at 762m/s but at 22km altitude, you'd be in a similar situation, unable to accelerate much, but in this case could get much more by dropping to 18km.

On those Flight Evelope charts, I imagine a climb profile being a smooth (if not straight) line going steadily up through as much as the red as possible.  The point where my imaginary line exits the blue, I know I'm going to have to have swapped to closed cycle or other rocket engines to keep accelerating.

The second example, AoA Curves > Lift/Drag ratio, shows you what Angle of Attack your vessel needs to be pointed at to get the most lift versus drag.  (This angle is measured from the root part I think, rather than the incidence of your wings.)  In that example, at sea level (altitude 0) and speed 100m/s, you would get the best lift/drag at about 2 degrees nose up from horizontal.  So, that would be the most economic angle for climbing at that altitude and speed (in this case probably at takeoff).

I hope that helps!

Linkageless

P.S. - I forgot to mention the part highlighting, a feature that drew me to the mod in the first place.  Drag highlight in particular is useful for spotting those parts that you may need to rethink when making a super slippery spaceplane!

[ttikkoo]

On 6/5/2021 at 12:03 AM, Linkageless said:

Hi @ttikkoo,

I'm still getting to grips with all that this mod can offer, and can't be sure my interpretation of any of it is all that great.  The best guide I know is from the start of this thread, and have worked stuff out from there.

An obvious example is the Flight Envelope > Excess Thrust, which shows you how much extra thrust you have available over what is needed for steady, level flight.  From @Booots's opening example, you can see the area in red in the middle of the graph is the best combination of speed and altitude for excess thrust, meaning the most acceleration is available, or alternatively I suppose they would be the most economical speed+altitudes to cruise at.

That example specifically indicates altitude 10088m (vertical scale) at speed 762m/s (horizontal scale) should allow you 539kN of thrust spare for accelerating.  If you were at the same altitude (10km) but already going 1450m/s, you'd struggle to find much excess thrust, so wouldn't be able to accelerate much more.  You could get just a little more speed if you climbed to 12km.   If you were at 762m/s but at 22km altitude, you'd be in a similar situation, unable to accelerate much, but in this case could get much more by dropping to 18km.

On those Flight Evelope charts, I imagine a climb profile being a smooth (if not straight) line going steadily up through as much as the red as possible.  The point where my imaginary line exits the blue, I know I'm going to have to have swapped to closed cycle or other rocket engines to keep accelerating.

The second example, AoA Curves > Lift/Drag ratio, shows you what Angle of Attack your vessel needs to be pointed at to get the most lift versus drag.  (This angle is measured from the root part I think, rather than the incidence of your wings.)  In that example, at sea level (altitude 0) and speed 100m/s, you would get the best lift/drag at about 2 degrees nose up from horizontal.  So, that would be the most economic angle for climbing at that altitude and speed (in this case probably at takeoff).

I hope that helps!

Linkageless

P.S. - I forgot to mention the part highlighting, a feature that drew me to the mod in the first place.  Drag highlight in particular is useful for spotting those parts that you may need to rethink when making a super slippery spaceplane!

Thanks heaps for the detailed reply! I'll have to find some time to test some planes soon!

[610yesnolovely]

On 6/18/2021 at 6:20 AM, ttikkoo said:

Thanks heaps for the detailed reply! I'll have to find some time to test some planes soon!

Also helpful as I just started looking at Wind Tunnel on a basic jet aircraft I built to see if I could improve some characteristics. There's a lot of information going on here, if anyone ever collected all the diagrams and text from the forum and made a Wiki page ... that would be great. Until then, I'll scratch my head, fiddle with some buttons, fly and crash and do it the Kerbal way. (I have no idea what I'm doing, lets eat more snacks and may be then it'll make more sense).

I've found that this goes fantastic with:

Thanks @Booots!

[ttikkoo]

3 hours ago, 610yesnolovely said:

Also helpful as I just started looking at Wind Tunnel on a basic jet aircraft I built to see if I could improve some characteristics. There's a lot of information going on here, if anyone ever collected all the diagrams and text from the forum and made a Wiki page ... that would be great. Until then, I'll scratch my head, fiddle with some buttons, fly and crash and do it the Kerbal way. (I have no idea what I'm doing, lets eat more snacks and may be then it'll make more sense).

I've found that this goes fantastic with:

Thanks @Booots!

Haha, yup, I feel the same pain. AtmosphereAutopilot is great, I find some autopilot mod is necessary for career modes involving anything to do with planes.

I've gotten somewhat decent at building planes the Kerbal way (i.e. after lots of failures and crashes) but I'm very keen on building my first spaceplane SSTO - it would be perfect for the tourism contracts. I've even got a tourist space station orbiting Kerbin but I just can't figure out SSTO's so I was hoping Kerbal Wind Tunnel would point me in the right direction. Fingers crossed!

[Tychonoir]

It appears this mod doesn't account for different intake performance? Is it assuming that the intake air is always met 100%? (I replaced all intakes with nosecones and it still thought my plane would fly)

While that seems like a reasonable shortcut, I believe I've noticed performance differences, particularly in regards to the effective base speed stat and performance vs mach.

Edited December 4, 2022 by Tychonoir

[Pds314]

Does this mod have compatibility with FAR (and produce sensible output data?)

I'm kinda guessing not because it would need to gather the data on lift and drag from FAR's own aerodynamic sim.

EDIT: read the thread and realized it's a long term goal but not currently supported.

Edited January 26, 2023 by Pds314

[Booots]

On 1/25/2023 at 9:37 PM, Pds314 said:

Does this mod have compatibility with FAR (and produce sensible output data?)

I'm kinda guessing not because it would need to gather the data on lift and drag from FAR's own aerodynamic sim.

EDIT: read the thread and realized it's a long term goal but not currently supported.

Sadly, no. I put a lot of time into trying to make it work, but it's just not working. And with the upcoming release of KSP 2 (get hyped!) I plan on recreating this mod in KSP 2 and leaving the KSP 1 version in its current state.

On 12/3/2022 at 11:47 PM, Tychonoir said:

It appears this mod doesn't account for different intake performance? Is it assuming that the intake air is always met 100%? (I replaced all intakes with nosecones and it still thought my plane would fly)

While that seems like a reasonable shortcut, I believe I've noticed performance differences, particularly in regards to the effective base speed stat and performance vs mach.

Aha, yes. It assumes you have sufficient intake air. Intake air consumption rates was just one of those things that I never bothered to figure out. I presumed that spaceplane designers would add intakes as necessary for their design and so I only deal with thrust and aerodynamics.

[DjPreside]

Hello Booots, I got back to the game after a long hiatus with a fresh install but I can't see the Wind Tunnel icon, is it because the mod is for KSP 1.12.3 and I'm playing on 1.12.5? Here's a log just in case. Back in the day I really loved to learn how things work with this tool, and now that I just passed an Atmospheric Flight Mechanics exam I came back to play around with it actually knowing what I'm doing, so I hope I can get it to work. Thanks in advance!

 

Edit: I don’t know how, but it seems I managed to fix it somehow. For some experiments I launched the game without Steam, I also launched a craft from the runway, reverted to SPH and the icon was there. Not sure what fixed it but I’ll gladly keep it!

Edited March 6, 2023 by DjPreside

[Chris Bolland]

Anyone know if this mod works with a rescaled solar system? I play at 6.4x scale, and I'm gonna test it and see when I get a chance.

[Booots]

On 3/21/2023 at 3:20 PM, Chris Bolland said:

Anyone know if this mod works with a rescaled solar system? I play at 6.4x scale, and I'm gonna test it and see when I get a chance.

Hey there! Sorry for the very slow reply. Life has been extremely busy since March (and will be for the next year or so). From what I remember, this mod takes all the atmospheric data from the celestial bodies stored in your game, so it likely will work. Let me know if you've run into any issues!

[etmoonshade]

On 3/21/2023 at 5:20 PM, Chris Bolland said:

Anyone know if this mod works with a rescaled solar system? I play at 6.4x scale, and I'm gonna test it and see when I get a chance.

And I'll reply another two months later from the above and say that I play on 10.625x and yes, it works fine for me.

[Pineapple Frenzy]

I don't know where this mod has been all my life. But I gotta say, it lifted KSP to a whole new level. 

As you can see in these images, Wind Tunnel showed a peak in the envelope at 12,912 m at 281 m/s.  Actual performance was pretty close, though I was able to exceed the expected ceiling by some margin.

I find I get the most accurate results  when the aircraft is oriented in the SPH with the main lifting foil pointed directly at the horizon.  Aircraft with a main wing that has plenty of incidence angle will appear to hang nose down.

 

[HereComesTheBoom]

@Booots Curious if this mod works with FAR. I'm currently testing it, but the heat map on the flight envelope doesn't populate, haven't tried without FAR yet