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


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On 14.09.2016 at 6:28 PM, Calvin_Maclure said:

The turbofan (the large 747 type TF) is Tweakscalable. Works both ways, bigger and smaller. Its great, tbh. Allowed me to work several aircraft models because of that. 

It shouldn't be tweakscalable - there is (mod compability) bug

Since I fixed this, I can't tweak scale engine.

Edited by raxo2222
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8 minutes ago, blowfish said:

Other than similar engines from B9 and a couple of other mods, no.  But they all have the same setup so you will be able to reach about the same speed with all.

So no atmospheric engines can run at higher speeds than 5 mach, faster than that and incoming air just melts engine insides.

And why CR2 Ramjet has so weak thrust? It cant generate more than 50 kN.

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7 minutes ago, raxo2222 said:

So no atmospheric engines can run at higher speeds than 5 mach, faster than that and incoming air just melts engine insides.

And why CR2 Ramjet has so weak thrust? It cant generate more than 50 kN.

At mach 5, the air is hot enough to melt most compressors.  The planned SABRE (which the RAPIER is loosely based on) gets around this by precooling the air before it enters the compressor (although AJE just sets the compressor temperature very high).  Even precooling has its limits though, and it appears that about mach 5.5 is the limit for the SABRE.

No idea about the ramjet really, it kind of uses a hack of the turbojet model, whereas it should be its own module.  I do plan on redoing it at some point.

Edited by blowfish
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Another note, despite how many air intakes you have, highest altitude is around 26.4 km. It due to oxygen requirement for airbreathing engines and it is set to be no oxygen in atmosphere above 26 km. It is still too thick atmosphere and your craft will going to melt down quite fast.

it is still useful if you plan your ascent carefuly, accelerate craft between 20 and 26 km in airbreathing mode in a way that you are near 5 mach you also pitching up steeper, so you don't use much speed in closed cycle mode until you reach space.

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9 minutes ago, kcs123 said:

Another note, despite how many air intakes you have, highest altitude is around 26.4 km. It due to oxygen requirement for airbreathing engines and it is set to be no oxygen in atmosphere above 26 km. It is still too thick atmosphere and your craft will going to melt down quite fast.

it is still useful if you plan your ascent carefuly, accelerate craft between 20 and 26 km in airbreathing mode in a way that you are near 5 mach you also pitching up steeper, so you don't use much speed in closed cycle mode until you reach space.

AJE has no handling for oxygen concentration (and I don't think there's any data on that anyway).  Engines will flame out below a certain flow threshold, but other than that flow (and thus thrust) will be completely linear with atmospheric pressure (although performance will vary at altitude due to temperature differences).

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This is just relevant part from stock "jetEngineBig.cfg"

// Do this first, so the engine gets the resultant air.
	MODULE
	{
		name = ModuleResourceIntake
		resourceName = IntakeAir
		checkForOxygen = true
		area = 0.03
		intakeSpeed = 30
		intakeTransformName = Intake
		occludeNode = top
		machCurve
		{
			key = 1 1 0 0
			key = 1.5 0.9 -0.4312553 -0.4312553
			key = 2.5 0.45 -0.5275364 -0.5275364
			key = 3.5 0.1 0 0
		}
	}

"checkForOxygen = true" is that check for airbreathing engines that require oxygen in atmosphere, otherwise it is considered as airintake is closed/not working at all.

I was messed with those some time ago in KSP 1.1.2. don't know how much stock game is changed since then. Also, can't tell how much influence AJE have on this, does it overwrite whole module or just alter some settings, so statment in previous post might not be accurate for AJE, but it is for stock engines with FAR combination. It also might be chance that altitude for oxygen is changed since I last time tested it.

EDIT:

Also, all of air intakes have that "checkForOxygen = true" variable, I probably just chosen engine with air intake by pure luck. Haven't investigated cfg files for a while, so take everything with a grain of salt.

Edited by kcs123
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@kcs123 In AJE, oxygen checking is done at the engine level, not the intake level.  In the stock case, there's a check for whether the atmosphere contains oxygen, and a minimum static pressure for the intake to work (which happens regardless of the oxygen check).

AJE has its own intake handling, and there are no checks other than the usual being underwater/shielded/out of atmosphere.

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22 minutes ago, blowfish said:

AJE has its own intake handling, and there are no checks other than the usual being underwater/shielded/out of atmosphere.

That explains things a bit. Thanks for info, I was using AJE just for a short time in KSP 1.1.2. and didn't have a chance to try it in KSP 1.1.3. so I missed that behaviour trough gameplay. Have to try it again when my "msut have mods" updates for 1.2.

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  • 3 weeks later...
  • 2 weeks later...

I'm not complaining, but what the.... I built a nice 10t drone. Then I've tried firespitter propeller engines, it hit 40m/s at end of runway with its 10kN of power, then I tried the propellers to most powerful one(2380 HP), still about 60m/s at end of runway, and its huuuge runway. Then I was so annoyed so I put there directly the AL-31FM turbofan, which have describtion of being used on Su-27. I thought ok, this will be enought, Su-27 have 30tons take off weight, no probelm can occur. Then...70m/s at end of runway. I'm simply not able to take off with 10 ton drone shaped in style of MQ-X american drones. Using FAR too, but it doesn't edit the engines. So why the Su-27 engine gave me 15.2kN of thrust at all, when most powerful porpeller engine gave me 14kN, both totally underpowered to take off with 10 ton aircraft...

Am I doing something wrong?

Thanks

Ave! Toonu

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@Toonu For the AL-31FM, do you have enough intake for it (it will say on the engine)?  It gives much more thrust than that for me

General 1.2 compatibility news: I have been working on it, but I've been busy and it's been somewhat slow.  I should have an update soonish though.

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5 hours ago, blowfish said:

@Toonu For the AL-31FM, do you have enough intake for it (it will say on the engine)?  It gives much more thrust than that for me

General 1.2 compatibility news: I have been working on it, but I've been busy and it's been somewhat slow.  I should have an update soonish though.

Thanks for reply, yes, it's drone, I have radial air intake, but I will start game and look at it, then edit post...

I thought I was doing smth wrong! :D

Toonu

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10 minutes ago, blowfish said:

So something occurred to me - how many people actually use AJE without FAR?  Given that a 1.2 compatible version of FAR has not materialized yet, is there any demand for a release before FAR updates?

I don't use AJE without FAR but there's some kind of 1.2 compatible test version of it.

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On 30/10/2016 at 9:13 PM, blowfish said:

So something occurred to me - how many people actually use AJE without FAR?  Given that a 1.2 compatible version of FAR has not materialized yet, is there any demand for a release before FAR updates?

Don't know about the rest but personally, I can wait.  I don't and can't and won't play KSP without it.

Edited by Maars
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On 5/27/2016 at 4:34 AM, blowfish said:

The precoolers don't actually do anything.  The best we could really do is just make them required for the engines to work, but that's not particularly interesting from a gameplay perspective.

1.7 km/s sounds about right ... they should take you to about Mach 5.5 before they seriously overheat (even precooled engines have their limits).

What happens in rocket mode after that is outside of AJE's domain.  However, it's been called that my attention that that SABRE's specific impulse in jet mode is probably too low.  Will look at fixing that at some point.

Err know this was a long time ago but if anything the rocket ISP is too low on the wiki for the Skylon it says the Saber engines have a specific impulse of 460 the KSP Saber is 340... if anything the specific impulse for the air breathing mode is too high the specific impulse on the page for the air breathing engines is 4100, but I must admit the engines do not seem to really ever exceed 4100 Specific impulse in real usage at maximum throttle.so it's probably about right for the air breathing part.

 

I wondered my craft was having to weight 108 tons more than the actual skylon when I was cheating and increased the heat tolerance of procedural tanks and used cyro balloons so my craft should be lighter than the proposed Skylon  not heavier.

Like super seriously I'm having to carry 273 Tonns of liquid Oxygen if I only have to cut that by 1/3 that means I can cut back of the hydrogen as well and also the containers which effect my final weight which then give me much more bang for the bunk.

That difference in ISP is MASSIVE!!! I could probably get the hole craft down to 200 - 250 Tons after that point I would go to using the proper heat shielded procedural parts which would bring me back upto 325 tons~ which is still as lot better than 433 Tons

And who should I speak to about this inconsistency so I can at least get if fixed on my install if not just plain old just getting it fixed.

Edited by etheoma
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