[1.0.5] Advanced Jet Engine v2.6.1 - Feb 1

[blowfish]

Unless you are going faster and managed to maintain the same dynamic air pressure for the craft at the new altitude.

Dimensionally, I would expect air flux to be proportional to rho*v rather than dynamic pressure (0.5*rho*v^2), but maybe there are other important effects I'm not accounting for.

[camlost]

Will this mod allow Realism Overhaul to work with just the DLL? Or do the parts need to be installed as well? I ask because I don't want any parts I don't need sucking up my memory (and memory is something I'm seriously watching).

AJE is partless. And it's not really a dependency for RO. If you don't want it/don't care about jets just skip it

[camlost]

updated xxx

- - - Updated - - -

updated for 0.90

[blowfish]

I'd like to contribute cfgs for this mod (MarkIV Spaceplane System). They might still need a bit of tweaking. Some notes on this:

• The SCIMITAR engine is just a RAPIER with more core area right now - not very interesting, but I'm not quite sure what else to change to improve it.
  
• The yellowjacket VTOL engine is an exact copy of the J85. Not very interesting and also not particularly useful for VTOL usage given the low thrust. Probably hard to push much more out an engine that size though.
  
• I increased the mass of the structural intakes to match up with the B9 intakes of the same shape and size. I'm not opposed to this change not happening though.
  

@PART[mk4scimitar]:FOR[AJE]:NEEDS[RealFuels]
{
@MODULE[ModuleEnginesFX],0
{
@PROPELLANT[LiquidFuel]
{
@name = LqdMethane
@ratio = 1
@DrawGauge = True
}
}
@MODULE[ModuleEnginesFX],1
{
@PROPELLANT[LiquidFuel]
{
@name = LqdMethane
@ratio = 0.45
@DrawGauge = True
}
@PROPELLANT[Oxidizer]
{
@name = LqdOxygen
@ratio = 0.55
}
}
}

@PART[mk4scimitar]:FOR[AJE]
{
%CoMOffset = 0, 2, 0
@title = AJE MkIV SCIMITAR
MODULE
{
name = AJEModule
IspMultiplier = 1
defaultentype = 2
useOverheat = false
isReactionEngine = true
acore = 12
byprat = 0
tinlt = 3000
tfan = 3000
tcomp = 4000
tt4 = 2450
tt7 = 4000
prat3 = 9
fhv = 18600
usePrat3Curve = True
maxThrust = 335
prat3Curve
{
key = 0.0 9.0 0 0
key = 2.0 8.0 0 0
key = 3.0 3.0 0 0
}
}
}

@PART[mk4yellowjacket]:FOR[AJE]
{
%CoMOffset = 0, 0.8, 0
@title = AJE General Electric J85 turbojet
@description = A basic, small turbojet powered by NASA EngineSim. Works from Mach 0 to 2. This one allows surface attachment for VTOL operation.
@mass = 0.2

@MODULE[ModuleEngines*]
{
@exhaustDamage = false
@maxThrust = 20
@heatProduction = 160
@useVelocityCurve = false
}
MODULE
{
name = AJEModule
IspMultiplier = 1
defaultentype = 1
acore = 3
byprat = 0
fhv = 17500
}
}

{
@description = Adjustable inlet, optimized for supersonic speed
@mass = 0.4

MODULE
{
name = AJEInlet
Area = 12
TPRCurve
{
key = 0.0 0.85 0 0
key = 1.0 0.96 0 0
key = 2.0 0.95 0 0
key = 2.5 0.90 0 0
key = 3.0 0.80 0 0
key = 4.0 0.65 0 0
key = 8.0 0.00 0 0
}
}
}

@PART[mk4intake-radial-2]:AFTER[AJE]
{
@description = Adjustable inlet, optimized for supersonic speed
@mass = 0.4

//Supersonic TPRCurve
MODULE
{
name=AJEInlet
Area=12
TPRCurve
{
key = 0.0 0.85 0 0
key = 1.0 0.96 0 0
key = 2.0 0.95 0 0
key = 2.5 0.90 0 0
key = 3.0 0.80 0 0
key = 4.0 0.65 0 0
key = 8.0 0.00 0 0
}
}
}

@PART[mk4cockpit]:AFTER[AJE]
{
// DSI TPRCurve
MODULE
{
name = AJEInlet
Area = 12
TPRCurve
{
key = 0.0 0.90 0 0
key = 1.0 0.97 0 0
key = 1.5 0.95 0 0
key = 1.8 0.90 0 0
key = 2.0 0.85 0 0
key = 3.0 0.60 0 0
key = 5.0 0.00 0 0
}
}
}

@PART[mk4intake-radial-1]:AFTER[AJE]

[Black-Talon]

AJE needs to be recompiled every time FAR updates.

Given this statement I assume per the patch notes that in order for this to work well with KSP 0.90 that I need to use FAR 14.5 (which is the 0.90 version of FAR) and recompile AJE against the FAR 14.5 binaries since the patch notes indicate FAR 14.4 as being the last version it was compiled against.

I plan to do this, but double checking my assumptions by asking never hurt...

[velusip]

I tried using AJE without RealFuels while it gets updated, but it doesn't seem to be balanced for stock engines. Fuel consumption and thrust are both way too high. Has anyone tried creating a sensible configuration for no RealFuels?

[camlost]

I tried using AJE without RealFuels while it gets updated, but it doesn't seem to be balanced for stock engines. Fuel consumption and thrust are both way too high. Has anyone tried creating a sensible configuration for no RealFuels?

I can't think of why. Keep in mind that the LiquidFuel's density is 5. There's no separate configs for RF or no RF

[Hodo]

I tried using AJE without RealFuels while it gets updated, but it doesn't seem to be balanced for stock engines. Fuel consumption and thrust are both way too high. Has anyone tried creating a sensible configuration for no RealFuels?

For the most part, AJE is meant to be used in the Realism Overhaul. Not in the stock KSP.

And if you think they are overpowered or to high... try getting an aircraft to break mach 3 in RO with one.

[DaMichel]

Well stock Jet engines are 4x more fuel efficient than they would be IRL. AJE engines have a realistic fuel consumption rate.

Does the consumption rate actually change if you install RealFuels? Because IIRC LiquidFuel is basically like Kerosine if RealFuels is not installed. With RealFuels you could use the higher energy density of H2 fuel to your advantage but that is about it, right?

AJE engines are only really OP at sea level. Their thrust drops off at altitude regardless of speed making them more difficult than stock engines (even when nerfed by FAR).

Edited December 20, 2014 by DaMichel

[blowfish]

Does the consumption rate actually change if you install RealFuels? Because IIRC LiquidFuel is basically like Kerosine if RealFuels is not installed. With RealFuels you could use the higher energy density of H2 fuel to your advantage but that is about it, right?

The energy density is set in the AJE cfg and doesn't change with/without RF. The only ones set to an energy density other than that of Kerosene are the RAPIER (liquid methane) and the B9 SABRE (liquid hydrogen).

[camlost]

Intake air is always stripped, what AJE does is to set Isp every frame, the actual fuel flow is handled by stock modules

[velusip]

Perhaps the energy density is fine. I mean, I don't know what the units are in stock and I haven't been following on with the developments of RealFuels. It just didn't seem right when trying AJE with stock.

It's hardly worth the effort to look into, especially since RealFuels is now updated (lol), but assuming the Mk1 liquidfuel tank contains less than 1000 litres of fuel: should this engine be able to throw it out the back so quickly?

[jstnj]

Cam we are currently investigating whether AJE is conflicting with FAR 14.5.1 in .90 where it affects drag on certain parts during reentry. A couple of people in the FAR thread (including myself) have had very low drag on the mk1 pod for instance, and can't slow to chute opening speeds before crashing into kerbin. Anything come to mind that might be conflicting? We could be wrong.

[velusip]

Just noticed there is no intake configuration for the MK1Fuselage in AJE. I'm not sure what configuration would be fair or how you have been calculating it from the model geometry, so I have no input atm.

edit: I'm just copying the nacelle config and dropping the intake area from 3 to 2. From eyeballing them side by side it appears about two thirds.

Edited December 21, 2014 by velusip
update, solution, hack

[camlost]

Perhaps the energy density is fine. I mean, I don't know what the units are in stock and I haven't been following on with the developments of RealFuels. It just didn't seem right when trying AJE with stock.

It's hardly worth the effort to look into, especially since RealFuels is now updated (lol), but assuming the Mk1 liquidfuel tank contains less than 1000 litres of fuel: should this engine be able to throw it out the back so quickly?

Think this way: how much fuel does a F-15 carry, which also uses 2 x F-100-PW-229? The density is 5, so the question is, with only 1500 litres of fuel, how long can the F-15 maintain supersonic flight at sea level? You can look it up somewhere, the answer is not long XD

[velusip]

It was a problem with a missing intake configuration and defaulting to silliness. However, here's an unrelated/new problem when using RealFuels:

After filling a fuel tank with only Kerosine (which by default contains resource definitions for LiquidFuel and Oxidizer), AJE's modified engines will not pull the Kerosine resource from that tank (or any similar tank). The engine will spool up and make some noise, but no fuel is consumed or thrust produced. Everything works fine when switching to a stock single fuel tank filled with kerosine.

Edited December 22, 2014 by velusip
added more detail

[camlost]

I'm the right person to ask, the only function of this mod is to change engines' thrust and Isp. How they draw resource and whatnot is not touched

@Everybody, I'm in the process of re-writing the engine code, making it infinite times more readable

[blowfish]

@Everybody, I'm in the process of re-writing the engine code, making it infinite times more readable

Good to hear

Any chance the new code will work in SI rather than imperial units?

[camlost]

Good to hear

Any chance the new code will work in SI rather than imperial units?

Absolutely, down with the imperialists!

[camlost]

https://github.com/camlost2/AJEsolverTester

Calling for public test

[velusip]

Okay, scratch anything I said earlier. Any information on how the Inlet configurations are defined? I mocked up some definitions for the missing inlets area (radialEngineBody = 5, radialEngineBodysmall = 1, nacelleBody = 5, MK1IntakeFuselage = 3), but I'm not sure how to derive appropriate TPR.

[blowfish]

https://github.com/camlost2/AJEsolverTester

Calling for public test

Will test as soon as I get a chance. Unfortunately I'm away from my Windows computer until early January so it'll have to wait until then. I'm looking over the code and it's definitely more readable now. I do have a few questions about the thermodynamic assumptions used but I think they'll wait until I've looked over the code a bit more/done a bit of research.

Okay, scratch anything I said earlier. Any information on how the Inlet configurations are defined? I mocked up some definitions for the missing inlets area (radialEngineBody = 5, radialEngineBodysmall = 1, nacelleBody = 5, MK1IntakeFuselage = 3), but I'm not sure how to derive appropriate TPR.

I think the area is in square feet (for now). For the TPR just copy one of the existing curves. There are three curves floating around in the configs - a subsonic (pilot tube) inlet curve, a transonic (divertless supersonic inlet) inlet curve, and a supersonic (adjustable ramp inlet) curve. If no inlet curve is specified then it uses an isentropic curve (usually for shock cones) which gives the highest possible TPR at all mach numbers. For the engine bodies you would probably want either the subsonic or transonic curves.

Edited December 24, 2014 by blowfish
spelling

[camlost]

New version up. All the jet engines and inlets redone. I haven't playtested every of them, and some mods are not updated for .90, so there could be bugs/balance issues.

[velusip]

New version up. All the jet engines and inlets redone. I haven't playtested every of them, and some mods are not updated for .90, so there could be bugs/balance issues.

Updated the stock Inlets by clearing the dangling definitions (small versions of parts removed) and added the 3 nacelles. Might be incomplete, but seems to work well so far.

[Gobur]

I find problem. When i use new FAR and AJE 2+ is problem with terminal velocity and bc parametrs. Standard capsule hiting Kerbin with speed Mach>1 (normal <200m/s). This look as bug on FAR - AJE