blowfish

[1.5.1] Advanced Jet Engine v2.12.1 (Nov 11)

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7 hours ago, lk00david said:

Is there any way to adjust an engines tolerable temperatures?

It's based on maxT3 in the configs.  You can increase that or turn on the ignore max temperature cheat (it's in the normal KSP cheat settings).  On a real engine, you would melt the compressor by going too fast though.

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Hey @blowfish,

Got a stock issue that is exacerbated by this mod. In stock when an airbreathing engine is deprived of intake air it results in a warning in the log  Waning Stageinfo simulation time exceeded. In stock, this isn't bad as it only gets logged once every few seconds. With AJE installed the pic below illustrates the issue. The log gets spammed with that warning every second as long as the engine is >0 throttle. I believe its related to the fact that with AJE "Prop. Requirement Met" % is always 0.00% as seen in the screenshot. I know that variable is from stock, but I wondered if you can do anything to "fix" this. Thanks!

613LnuU.png

Steps for reproduction

  1. Load up stock Aeris 3a
  2. Stage at 0 throttle
  3. Increase throttle
  4. Observe console
  5. Throttle to 0
  6. Observe console, spam stops

Steps for stock reproduction

  1. Load up stock Aeris 3a
  2. Stage at 0 throttle
  3. Increase throttle
  4. Observe console
  5. Throttle to 0
  6. Observe console
  7. Close all intakes
  8. Increase throttle
  9. Observe console Warning every few seconds

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I am having an issue where my custom engine randomly explodes on the pad as soon as it loads... I can't seem to figure out why and I need help

Thank You :D

https://pastebin.com/5k7gQ6z1

Edited by Val
Moved to pastebin

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I cleaned up the long post as it seemed to affect mobile users negatively.

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Posted (edited)

I'm in the long ongoing process of rewriting AJE-Extended from the ground up. In the process, I'm trying to improve the engine templates, but I'm having some trouble reconciling some of the data. Specifically, I'm not sure what the supercharger settings for piston engines actually refer too. Is there any information what the boost, rated and cost fields actually are? Are they horsepower increases/costs at altitudes or something else?

ETA:

Looking at the source code, it appears rated is the altitude, cost is the HP loss running the supercharger and the boost fields are the pressure boost to the engine airflow. I'm just not sure how to convert engine specs to those values. They seem to be multipliers for ambient pressure, I'm just not sure how they're derived from engine specs.

ETA:

I'm starting to think that the boosts are given in inches of mercury (Hg). That seems to match up somewhat with the psi ratings I have. Just seems a fairly archaic measurement.

Edited by Citizen247

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@blowfish

Have you ever considered simulating the effects of water and/or oxygen injection for turbine engines? Is that something AJE could simulate? :)

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1 hour ago, Svm420 said:

@blowfish

Have you ever considered simulating the effects of water and/or oxygen injection for turbine engines? Is that something AJE could simulate? :)

It's unfortunately not possible in the current, very basic, thermodynamic model.

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Posted (edited)

@blowfish I would like to ask you about one thing. Isn't the specific impulse for RAPIER engine a bit too low at static conditions, just before takeoff? I am asking about 100% throttle with afterburner.

AScLzMe.jpg

For a comparison most of turbojets and turbofans have something like 2000-2500 ISP with full afterburner on. At higher altitudes and speeds it is ok, comparable with other engines but i feel like I am loosing waay too much fuel just for takeoff and climbing.  Another thing - specific energy for methane is a bit higher than for a regular jet fuel, shouldn't this be reflected in specific impulse?

 

 

 

EDIT: just noticed that this was fixed on github 2 years ago :)  https://github.com/KSP-RO/AJE/commit/e60ce68dcb9c11f0d89d79a7b543f6e33c20f071#diff-7712b54154072776670435a729c7f4ea so I will just apply new settings to my installation.

Edited by winged

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1 minute ago, winged said:

@blowfish I would like to ask you about one thing. Isn't the specific impulse for RAPIER engine a bit too low at static conditions, just before takeoff? I am asking about 100% throttle with afterburner.

AScLzMe.jpg

For a comparison most of turbojets and turbofans have something like 2000-2500 ISP with full afterburner on. At higher altitudes and speeds it is ok, comparable with other engines but i feel like I am loosing waay too much fuel just for takeoff and climbing.  Another thing - specific energy for methane is a bit higher than for a regular jet fuel, shouldn't this be reflected in specific impulse?

It probably is.  The RAPIER (and similar) are hacks of the turbojet module really, so I'm not really sure of a good way to fix this yet.  I've been looking at an alternate thermodynamic model for these engines but haven't generated anything I like yet.

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1 minute ago, blowfish said:

It probably is.  The RAPIER (and similar) are hacks of the turbojet module really, so I'm not really sure of a good way to fix this yet.  I've been looking at an alternate thermodynamic model for these engines but haven't generated anything I like yet. 

Yes, but I just noticed that in newer AJE versions FHV was increased from 36 mln to 45 mln which is supposed to increase efficiency so I will apply that.

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I'd like to adapt my Explodium Breathing Engines part mod to use the AJE modules. For the most part, the engines are clones of the stock jets that use oxidizer and 'explodium vapour' found on worlds with methane or similar hydrocarbon vapour.

I've tried AJE on Tellumo, a super-Kerbin in Galileo's Planet Pack with an oxygen atmosphere and ten times the air density at sea level. AJE models the effects of higher pressure and density remarkably well! I noticed I had to watch my inlet area to match the engines I used, and added intakes if needed.

But now I'd like to replicate this on Eve, Catullus, Tekto, and so forth. While the engine parts should translate well, it's the intakes, or "harvesters," that I expect to have trouble with. Right now ExV Engines need parts that use ModuleResourceHarvester to extract ExV from the air, because I can't just use ModuleResourceIntake and change the resource. Doing that requires me to set checkForOxygen to False, making the engines work anywhere with an atmosphere; even Duna.

Is the AJEInlet module adaptable to use a resource other than IntakeAir, while still supplying inlet area to the engines and only working if the resource is in the air?

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Posted (edited)

Figured it out/forget this post

Edited by Wolf123

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On 6/12/2019 at 5:45 PM, Gordon Fecyk said:

I'd like to adapt my Explodium Breathing Engines part mod to use the AJE modules. For the most part, the engines are clones of the stock jets that use oxidizer and 'explodium vapour' found on worlds with methane or similar hydrocarbon vapour.

I've tried AJE on Tellumo, a super-Kerbin in Galileo's Planet Pack with an oxygen atmosphere and ten times the air density at sea level. AJE models the effects of higher pressure and density remarkably well! I noticed I had to watch my inlet area to match the engines I used, and added intakes if needed.

But now I'd like to replicate this on Eve, Catullus, Tekto, and so forth. While the engine parts should translate well, it's the intakes, or "harvesters," that I expect to have trouble with. Right now ExV Engines need parts that use ModuleResourceHarvester to extract ExV from the air, because I can't just use ModuleResourceIntake and change the resource. Doing that requires me to set checkForOxygen to False, making the engines work anywhere with an atmosphere; even Duna.

Is the AJEInlet module adaptable to use a resource other than IntakeAir, while still supplying inlet area to the engines and only working if the resource is in the air?

I took a look at the code and there is indeed an assumption of the atmosphere containing oxygen.  I don't think this would trivial to change ... a lot of the thermodynamics assume that the atmosphere is roughly that of earth's and that it contains oxygen as the oxidizer burnt with onboard fuel.

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20 hours ago, blowfish said:

I took a look at the code and there is indeed an assumption of the atmosphere containing oxygen.  I don't think this would trivial to change.

Certain things stand out just looking at the part configurations. Notably, the engines don't consume Intake Air; there's only one Propellant{} section. The inlets gather Intake Air but don't seem to do anything with it. I guess the magic happens in the interaction between AJEInlet and ModuleEnginesAJEJet.

I suppose I could clone these modules and apply the 45% ISP reduction rule I came up with; I describe the chemistry on the ExV Wiki, and use a "checkForExV" flag that checks the resources config for a world, but I'd have to make a similar assumption that any world with hydrocarbon vapour would have a certain universal percentage. It doesn't look like AJE treats Laythe differently from Kerbin, for instance.

It wouldn't be accurate, but we don't know what 'accurate' is until we try building an engine for Titan's methane atmosphere in reality.

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On 6/17/2019 at 6:58 PM, Gordon Fecyk said:

Certain things stand out just looking at the part configurations. Notably, the engines don't consume Intake Air; there's only one Propellant{} section. The inlets gather Intake Air but don't seem to do anything with it. I guess the magic happens in the interaction between AJEInlet and ModuleEnginesAJEJet.

I suppose I could clone these modules and apply the 45% ISP reduction rule I came up with; I describe the chemistry on the ExV Wiki, and use a "checkForExV" flag that checks the resources config for a world, but I'd have to make a similar assumption that any world with hydrocarbon vapour would have a certain universal percentage. It doesn't look like AJE treats Laythe differently from Kerbin, for instance.

It wouldn't be accurate, but we don't know what 'accurate' is until we try building an engine for Titan's methane atmosphere in reality.

Part of the problem is that KSP has a hard-coded flag for whether an atmosphere has oxygen, which is easy to check, but checking for other atmosphere components would be more complicated and would likely require some configuration files to show what, and how much, is available where.

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Does AJE need FAR to work or is it independent of FAR?  I was wondering because attempting when I downloaded AJE on last night if was forcing a FAR download as well.  On the website it doesn't show any requirements for FAR and so I did a manual install.  i wasn't looking to add FAR but will if I need to.  If makes any difference, my intention was to use the mod on my play with the JNSQ planet pack.  I am also using the RealFuels Stock Config.

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6 hours ago, Galland1998 said:

Does AJE need FAR to work or is it independent of FAR?  I was wondering because attempting when I downloaded AJE on last night if was forcing a FAR download as well.  […]  If makes any difference, my intention was to use the mod on my play with the JNSQ planet pack.

AJE can work without FAR but, as the original post explains, the AJE jets may seem underpowered without it. If you're going to use closer-to-realistic engines might as well use a closer-to-realistic aerodynamic model.

And don't be afraid of using FAR with JNSQ... if your JNSQ installation seems to randomly crash, try removing TweakChute from the JNSQ install. FAR's RealChute Lite replaces ModuleParachute, which TweakChute adjusts, but I've had my JNSQ-based KSP installation crash on startup. Since RealChute Lite replaces what TweakChute adjusts, you won't lose any functionality and it's one less plugin DLL to contend with.

To avoid crashtastic results, I'd start with a clean KSP installation outside of the SteamApps folder so Steam doesn't update it under your feet. Then follow JNSQ's install instructions until you have a basic working install plus JNSQ and its prerequisites. Only then start adding FAR, AJE, and others. Use the version of Modular Flight Integrator included with Kopernicus; both FAR and AJE depend on MFI, but Kopernicus is hard-coded to whatever version of MFI it ships with.

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Posted (edited)

@blowfish

Trying to make config for the NK-12. For some reason when using a gear ratio of 0.094, or 1:10.6, it causes the engine to constantly flip from nominal to starter on not functioning properly. In this state throttle has no effect on engine output it has those same outputs 1-100% Any idea whats going on?

Spoiler

6trEp4S.png

click for other pic

Spoiler

@MODULE[ModuleEngines*]
	{
		@name=ModuleEnginesAJEPropeller
		%IspMultiplier = 1
		%useOxygen = true
		// %compression = 13.1
		// %engineType = Turbine
		minRPM = 2000
		maxRPM = 9250
		power = 14795
		gearratio = 0.094
		BSFC = 8.47E-8
		ramAir = 1
		exhaustThrust = 2.78
		meredithEffect = 0.002
		boost0 = 0
		rated0 = 0
		boost1 = 0
		rated1 = 0
		switchAlt = -1
		turbo = false
		wastegateMP = 52.5
		propName = HS6501A-0x4
					
			%propDiam = 5.6
							
			 //8-bladed
			%CtTweak = 2
			%CpTweak = 2
	}

 

 

Edited by Svm420

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3 hours ago, Svm420 said:

@blowfish

Trying to make config for the NK-12. For some reason when using a gear ratio of 0.094, or 1:10.6, it causes the engine to constantly flip from nominal to starter on not functioning properly. In this state throttle has no effect on engine output it has those same outputs 1-100% Any idea whats going on?

  Reveal hidden contents

6trEp4S.png

click for other pic

  Reveal hidden contents


@MODULE[ModuleEngines*]
	{
		@name=ModuleEnginesAJEPropeller
		%IspMultiplier = 1
		%useOxygen = true
		// %compression = 13.1
		// %engineType = Turbine
		minRPM = 2000
		maxRPM = 9250
		power = 14795
		gearratio = 0.094
		BSFC = 8.47E-8
		ramAir = 1
		exhaustThrust = 2.78
		meredithEffect = 0.002
		boost0 = 0
		rated0 = 0
		boost1 = 0
		rated1 = 0
		switchAlt = -1
		turbo = false
		wastegateMP = 52.5
		propName = HS6501A-0x4
					
			%propDiam = 5.6
							
			 //8-bladed
			%CtTweak = 2
			%CpTweak = 2
	}

 

 

Unfortunately I have no knowledge of the propeller code.  That's more @camlost's territory

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Posted (edited)
On 7/2/2019 at 2:10 AM, Svm420 said:

@blowfish

Trying to make config for the NK-12. For some reason when using a gear ratio of 0.094, or 1:10.6, it causes the engine to constantly flip from nominal to starter on not functioning properly. In this state throttle has no effect on engine output it has those same outputs 1-100% Any idea whats going on?

  Hide contents

6trEp4S.png

click for other pic

  Hide contents


@MODULE[ModuleEngines*]
	{
		@name=ModuleEnginesAJEPropeller
		%IspMultiplier = 1
		%useOxygen = true
		// %compression = 13.1
		// %engineType = Turbine
		minRPM = 2000
		maxRPM = 9250
		power = 14795
		gearratio = 0.094
		BSFC = 8.47E-8
		ramAir = 1
		exhaustThrust = 2.78
		meredithEffect = 0.002
		boost0 = 0
		rated0 = 0
		boost1 = 0
		rated1 = 0
		switchAlt = -1
		turbo = false
		wastegateMP = 52.5
		propName = HS6501A-0x4
					
			%propDiam = 5.6
							
			 //8-bladed
			%CtTweak = 2
			%CpTweak = 2
	}

 

 

When I worked on nk12 settings for aje-extended I found the aje really doesn't like high powered engines. Anything over 10,000hp seems to flip out and cause some really odd issues. I've spent many hours trying to get something to work and never got anywhere. In the current version I've just capped the hp.

It's also optimised for piston engines, you can't use turbine RPMs and gear ratios, you have to sort of kludge it a bit.

Edited by Citizen247

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