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

[NathanKell]

They probably need to be updated for B9 v5.x.

[camlost]

I had deleted these engines out of the pack because they were full of bugs. I see you corrected one of them, but any ideas why they show up like this? Keep in mind the J58, the actual replacement and not one of the added engines, works perfectly fine. It's only the 'duplicates' that have troubles like this. If it's not obvious from the picture, I'm at 0 thrust because the engines are not on yet they have no sound and they always output the same smoke trail and engine effect:

http://cloud-4.steampowered.com/ugc/35228661656702633/2BD114CAFD34137CAA4C44B3ECE731C836525A9A/

Judging from the flame you're not running B9 v5 correctly. The flames don't look like that any more. Or it could be a MM problem

[Hyomoto]

Judging from the flame you're not running B9 v5 correctly. The flames don't look like that any more. Or it could be a MM problem

Maybe, except the engine from B9 works properly. Only +PART modules work improperly, and only the ones that you defined EFFECT for. So, yes, it could be MM. The tutorials for Hot Rockets and Smoke Screen are crap to say the least, so it's not something a cursory comparison resolved. All I can say is the flames do look like that, you defined it. It's an effect included with Hot Rockets. Your definition appears to have been copy-pasted from a stock definition from the Hot Rockets stock cfg. Doesn't explain why it doesn't work though, but I don't have enough time to really dig into it right now.

[amo28]

Maybe, except the engine from B9 works properly. Only +PART modules work improperly, and only the ones that you defined EFFECT for. So, yes, it could be MM. The tutorials for Hot Rockets and Smoke Screen are crap to say the least, so it's not something a cursory comparison resolved. All I can say is the flames do look like that, you defined it. It's an effect included with Hot Rockets. Your definition appears to have been copy-pasted from a stock definition from the Hot Rockets stock cfg. Doesn't explain why it doesn't work though, but I don't have enough time to really dig into it right now.

Something about the EFFECTS{} section in J58's config was using old HotRockets, I think. I replaced it with the config from B9:

EFFECTS
    {
        power
        {
            MODEL_MULTI_PARTICLE_PERSIST
            {
                name = b9_jet_d30_flame
                modelName = B9_Aerospace/FX/HR/flamejet3
                transformName = thrust_transform
                emission = 0.66 0
                emission = 0.67 2.42 1.35 1.35
                emission = 1.0 2.5 0 0
                speed = 0.66 3.75
                speed = 1.0 4.575
                energy = 0.66 0.5
                energy = 1 1
                // under/over expansion
                logGrow
                {
                    density = 1 -0.9
                    density = 0.4 1
                    density = 0.05 5
                    density = 0.005 40
                }
                linGrow
                {
                    density = 0.05 0 0 0
                    density = 0.005 3
                    density = 0 30
                }
                size
                {
                    power = 0 1.295
                    power = 1 1.58
                    density = 0.4 1
                    density = 0.05 0.87
                    density = 0.03 0.55
                    density = 0.02 0.45
                    density = 0.005 0.4
                    density = 0 0.25 0 0
                }
            }

            AUDIO
            {
                name = b9_jet_d30_sound_afterburner
                channel = Ship
                clip = sound_rocket_hard
                volume = 0.66 0
                volume = 0.67 1 3 3
                volume = 1 1.33 0 0
                pitch = 0.66 1
                pitch = 1 0.66
                loop = true
            }

            AUDIO
            {
                name = b9_jet_d30_sound_jet_deep
                channel = Ship
                clip = sound_jet_deep
                volume = 0   0    0     25
                volume = 0.1 1.12 0.145 0.145
                volume = 1.0 1.25 0.145 0
                pitch = 0 0.3
                pitch = 1 1
                loop = true
            }
        }
        running
        {
            MODEL_MULTI_PARTICLE_PERSIST
            {
                name = b9_jet_d30_smoke
                modelName = B9_Aerospace/FX/HR/smokejet
                transformName = thrust_transform
                speed = 0.0 0.8
                speed = 1.0 1

                emission
                {
                    power = 0.07 0 0 0
                    power = 0.2 0.4 2.91 2.91
                    power = 1.0 1.1 0 0
                    density = 0.001 0 0 0
                    density = 0.002 1 0 0
                }

                energy
                {
                    power = 0 0.2
                    power = 1 3.2
                    externaltemp = -10 1
                    externaltemp = 1 0
                    mach = 0 1
                    mach = 10 10
                }

                offset
                {
                    mach = 0 1
                    mach = 6 10
                }

                logGrow
                {
                    density = 0 2
                    density = 1 0.9
                    density = 10 0
                }
            }

            AUDIO
            {
                channel = Ship
                clip = sound_jet_low
                volume = 0   0    0    25
                volume = 0.1 1.12 0.22 0.22
                volume = 1   1.32 0.22 0
                pitch = 0 0.3
                pitch = 1 1
                loop = true
            }
        }
        engage
        {
            AUDIO
            {
                channel = Ship
                clip = sound_vent_medium
                volume = 1
                pitch = 2
                loop = false
            }
        }
        disengage
        {
            AUDIO
            {
                channel = Ship
                clip = sound_vent_soft
                volume = 1
                pitch = 2
                loop = false
            }
        }
        flameout
        {
            PREFAB_PARTICLE
            {
                prefabName = fx_exhaustSparks_flameout_2
                transformName = thrust_transform
                oneShot = true
                localOffset = 0, 0, 2.53
            }

            AUDIO
            {
                channel = Ship
                clip = sound_explosion_low
                volume = 1
                pitch = 2
                loop = false
            }
        }
    }

[amo28]

Camlost,

Got a question for you on the interaction between AJE and RealFuel's jet changes. RealFuels adds the MODULEHYBRIDENGINES module which allows us to "Change engine mode" in order to enable afterburner. However, AJE allows us to enable afterburner after increasing throttle past 75%.

Which is the correct way of enabling afterburner? Using RealFuels afterburner seems to not use AJEModule, though I don't really know that for sure. Using AJE's afterburner ability seems to give me more realistic thrust.

Should I remove ModuleHybridEngines so I just rely on AJE's changes?

[Hyomoto]

Something about the EFFECTS{} section in J58's config was using old HotRockets, I think. I replaced it with the config from B9.

I am working towards trying something like this, but I wanted to figure out what exactly was the cause. This is definitely the quicker solution

Edited November 8, 2014 by Hyomoto

[camlost]

Camlost,

Got a question for you on the interaction between AJE and RealFuel's jet changes. RealFuels adds the MODULEHYBRIDENGINES module which allows us to "Change engine mode" in order to enable afterburner. However, AJE allows us to enable afterburner after increasing throttle past 75%.

Which is the correct way of enabling afterburner? Using RealFuels afterburner seems to not use AJEModule, though I don't really know that for sure. Using AJE's afterburner ability seems to give me more realistic thrust.

Should I remove ModuleHybridEngines so I just rely on AJE's changes?

There's still engines using ModuleHybridEngines? That's weird, are you sure about that in the new RF? They should always be removed if AJE is used.

[amo28]

There's still engines using ModuleHybridEngines? That's weird, are you sure about that in the new RF? They should always be removed if AJE is used.

You're right. My fault. Must've screwed up an RF update somewhere along the lines and still had the B9_JetEngine.cfg.

All good now! Sorry about that.

[Hyomoto]

Well, it took a while and a lot of designs (and two casualties) but I finally built a craft to break the 15km barrier. Getting used to the ramjets was more difficult that I'd expected, if you can't get them up to Mach 2 you might as well have just used a different engine altogether! The first KSR-2 Hypersonic suffered a flat spin from which I could not recover and crashed, but after a mild revision to the canard structure and a slight adjustment to the gear positioning and it was able to complete the mission I built it for. I can understand why some people might shy away from this mod, but it sure makes building and flying your planes that much more enjoyable! Cruising speed Mach 3.2 at 16km. At full afterburner you can push the operational ceiling up to 20km.

[camlost]

I can understand why some people might shy away from this mod

Interesting, which people?

[Hyomoto]

Should I start with every single person who doesn't use FAR or everyone who does use FAR but doesn't also use AJE?

[camlost]

Should I start with every single person who doesn't use FAR or everyone who does use FAR but doesn't also use AJE?

That's not the point. People do not use AJE because they don't know/don't care/don't build airplanes, which is fine. but I haven't seen a lot of people complaining to me that the game is too hard, or demand some kind of nerf.

[Hyomoto]

Then what exactly is the point, camlost? I also wasn't complaining that the game is too hard or demanding some kind of nerf. I simply said, I understand why some people choose not to use AJE. It isn't because they don't know or care about airplanes or even aerodynamics, part of that list is people use FAR for the exact purpose of building planes and they consider themselves enthusiasts. They don't use AJE because it limits behaviors they've grown accustomed to. FAR doesn't make building airplanes harder, in most cases it makes flying them easier because they respond in sensible ways. AJE does make flying more difficult, it imposes harsh limitations on performance and design, and if there is a part of the human condition that is well-documented, it's a aversion to difficulty and change.

Of course it's 'fine' if people choose not to use it. I never said it wasn't. You have a odd habit of responding to things I didn't write. I was pointing out why I liked using it, not making a case against people who don't. I didn't realize that your mod wasn't designed to inspire happiness or accomplishment, I've been misusing it this whole time. I apologize, it's just that I kept having fun.

[DaMichel]

On parts exploding, that's something to be discussed about DRE. I've made a SSTO with B9 Sabre that looks like the Skylon, in RSS. The key is to use light materials for the fueslage from Procedural parts. However, PP and pWings don't have heat shield, so DRE had to be disabled.

Do you have pics of this to show?

I've just recently started playing with the 6.4x rescale in addition to AJE. The second thing i tried, after getting a capsule to orbit was building a Skylon replica. I'm using RealFuels, StockalikeRF configs and Procedural Parts, too. But i just cannot get enough DV together. If i just pack LO2/LH2 and a small Rapier engine i get like 8km/s and a TWR of 0.8. But once wings and stuff are added i only have about 4.5 km/s left. That is in rocket mode with H2 for air breathing mode already burned away.

Guess i have to think Kerbal and build bigger ...

[jrandom]

Do you have pics of this to show?

I've just recently started playing with the 6.4x rescale in addition to AJE. The second thing i tried, after getting a capsule to orbit was building a Skylon replica. I'm using RealFuels, StockalikeRF configs and Procedural Parts, too. But i just cannot get enough DV together. If i just pack LO2/LH2 and a small Rapier engine i get like 8km/s and a TWR of 0.8. But once wings and stuff are added i only have about 4.5 km/s left. That is in rocket mode with H2 for air breathing mode already burned away.

Guess i have to think Kerbal and build bigger ...

I attempted to build a skylon-style SSTO in full-scale RSS/RO and found that the amount of liquid hydrogen and oxygen I needed for enough delta-v to get to orbit turned out to be the same volume as the real-life thing. It barely fit in the SPH and had a diameter of 13 meters or so. Yay physics.

[camlost]

@Hyomoto,

My point is, I think it is more difficult to move from non-FAR to FAR, having to deal with stalling, dynamic pressure etc. That's why we see many people complaining in the FAR thread, demanding nerfs. But that didn't make people go away from FAR, generally. I think the human condition here is exactly the opposite: embrace difficulty and change. That's why I'm curious of what you said.

@DaMichel

Like jrandom said, you have to go very big. Mine was 5m in diameter, about 70m long, packing about 60k LH2 and 16k LO2. 1/3 of the LH2 was burnt in the air-breathing mode. Takes off at almost 400 knots, so the runway's not long enough without the help of SRBs

At this point it has little to do with AJE, but more like rocket design. To get that 6km/s delta-v, 85% of the take-off weight has to be fuel, thus you have to use rocket parts instead of B9. The SABRE rates about 700kN on sea level, and you generally need ~0.5 surface TWR for supersonic airplanes. So the sensible design is ~300 tonnes at take-off

[Hyomoto]

@Hyomoto,

My point is, I think it is more difficult to move from non-FAR to FAR, having to deal with stalling, dynamic pressure etc. That's why we see many people complaining in the FAR thread, demanding nerfs. But that didn't make people go away from FAR, generally. I think the human condition here is exactly the opposite: embrace difficulty and change. That's why I'm curious of what you said.

Fair enough, then perhaps I also have a habit of taking what you write out of context. I do, however, disagree. Players feel the same way about KSP when they first start. Until you have a little understanding of what makes a rocket move and the forces that act upon it, just getting to orbit seems impossible. Over time and explosions we learn more about deltaV, drag, terminal velocity and staging, and eventually going into orbit seems trivial. Some people cannot dock, they get MechJeb to do it for them despite being a simple concept. Really, FAR isn't so different. If you don't understand what makes a plane fly, you are just as bound to blind luck and failure until you learn more. The reason it seems harder is more likely because FAR exposes a bunch of numbers and graphs, KSP has some bugs (wheel colliders anyone?) that make it harder generally, and keyboard flying sucks. In the end however, just as people ask each other for advice on how to build better rockets, people ask for advice on how to make their planes fly. Eventually it becomes second-nature just like rocketry. AJE is really not so different.

That being said, demands for 'nerfs' is the aversion to difficulty and change. Many people tout realism as the gold standard but hate permadeath and have no issue with regenerating health. You have to keep in mind, most people do not start out with mods and some are against them outright. Technically speaking, while FAR and AJE are nerfs on more unrealistic behaviors, and though some will inevitably come to enjoy the added challenge and limitation, most simply will not. I think someone who would look for a mod like this is already more likely to enjoy the challenge and change to begin with and it is there I certainly agree with you. Just not for humanity as a whole.

Edited November 10, 2014 by Hyomoto

[DaMichel]

Thanks to both of you for the tips. So yeah bigger is better Its a pity that this doesn't fit stock like sizes anymore but i guess that is the price to pay for realism

In my opinion the issues with difficulty are really secondary with mods like AJE or FAR. I rather consider them as cool toys for those of us who want to play with "real jet engines" because of curiosity or just for the sake of technical/physical correctness. So thanks for making AJE

EDIT:

Payload: just the cockpit an a Kerbal. I didn't even bother with RCS fuel or electricity. So i guess it's time for a rescue mission.

Edited November 11, 2014 by DaMichel

[kcs123]

This is simple to say great mod. It is not too difficult to make good SSTO once you figure out how they actualy works. I just needed to put more LF fuel tanks instead of LFO to maintain my craft abilities.

Anyway, I was delivered 30t worth payload to orbit. 40t raw craft mass, 30t payload and 20t fuel. I didn't count additional equipment in cargo bay like IR parts and TAC life support containers.

More info with link for craft file is in SSTO Spaceplane Airplane Design Contest II Akademy-Awards thread.

Here is galery from my test to orbit with modified craft for AJE.

Thanks for making this mod, and I have a question. I'm not sure how afterburner works. Is it just throttle adjustment - below 66% is cruise mode and anything above is afterburner ?

I'm asking because as you can also see in pictures in galery, sabre engines always shows "cruise" mod, regardless of throttle settings. Is it jus a visual bug in B9 parts or I need to press some key for afterburner ?

Also, when I'm still on topic, what throttle settings should be most fuel efficient at given altitude ? I still wasn't fully figured out graph in OP post.

[Hyomoto]

The 'most efficient' position will be dependent upon your plane. I have a low altitude, low-speed cargo plane that has an average ISP of above 4,000 at full throttle. It can barely push Mach 1 and has to be lower than 3km above sea level, but has a range of about 2,400 kilometers. I have a high-altitude, high-speed reconnaissance aircraft that averages mach 3.5 at 15km at 66% throttle, but an ISP of only about 1,400 with roughly the same operational distance. It's been a thorn in my side for a while now, what is the best way to circumnavigate Kerbin? That's roughly the distance I would need to hit all my waypoints and return to the KSC. Anyways, you'll have to find where your fuel consumption is lowest and your speed highest. You may have nearly the same consumption, but doing two times the speed is obviously better. It's going to depend on a lot of factors, you'll have to find out which ones they are for your craft.

[jrandom]

If you can get up to the really thin atmosphere (don't know what it is on Kerbin, but in RSS it's around 25-26km, you can easily build small Mach 3+ craft with a range of 3000-4000km. This trick is to build something with just enough wingspan that it can fly that high, but not so much wing that the drag significantly cuts down on your range.

[camlost]

@Damichel, I never thought that would worked! Because the SABRE S has a smaller TWR than SaBRE M. Also I found that the SABRE M had 2920kN in rocket mode, which is weird because it should be 1350kN. I corrected that in the dev version on github. Another thing is that I think the RAPIER should use LqdMethane instead kerosene (which is ridiculous)

@kcs123, The SABRE and RAPIER are special, their afterburner cannot be turned off because they are actually rockets. Generally you want to turn off AB most of the time to save fuel, like real pilots do. But SSTOs are special cases

@Hyomoto, The J58 is also kind of special. I believe in certain high speed conditions, with or without AB makes very little difference in Isp

[kcs123]

Well, without AJE mod, I have usualy search in FAR graph AoA and speed that will give most L/D in subsonic and supersonic area. I have tried to clibm high as possible with subsonic speed where craft have best L/D ratio until it can't climb more due to thin atmosphere. At that point I accelerate to supersonic speed in area where L/D is stable again, usually near 1.4 mach on my craft design. Then I climb up again at lowest stable supersonic speed before I make finall push to 5.5 or 6 mach (depends on engine and used mods) before I switch to rocket mode. To make whole trip less tedious I have set throttle to just slightly accelerate, so I need less time to accelerate when I reach higher altitude.

Similar thing seems to work even with this mod, but a bit more complicated. I have monitored closely both, engine stats, ship weight/acceleration and remaining dV. But I just haven't figure out is it better to push to full throttle or it is better to continue on cruising mode. While at some moment I have more then enough thrust on low throttle, when I reach certain altitude, craft start to loose height due to low atmosphere density. At that point I usualy have enough speed due to continious acceleration, but not with this mod.

With this mod there was moment that I have to set full throttle to keep the same altitude, but I think that is not always the best thing to do it.

I guess that I have to do few more test runs to find optimal procedure. Thanks for info, I guess that I'm close to optimal route with fuel economy.

Btw, sabre engines shows ~5500 ISP on flight until I reach higher altitude and gain more speed, but sometimes I got higher ISP on low throttle and sometimes higher with full throttle setttings. That depends on craft speed/altitude and that is main reason why I have asked question in the first place.

It's a bit confusing to figure out optimal routine.

EDIT:

@camlost - Thanks, that explains confusing info on right click to sabre engines, not a big deal that influence gameplay, I was just curious. It seems that you have wrote post at the same time as I wrote this.

Edited November 11, 2014 by kcs123

[camlost]

@kcs123, I wondered how did you build such a powerful machine, using high AR wings, which are not intended for supersonic flights, still reaches orbit. Then I see you're not using RF. The SABRES burn hydrogen, thus its high Isp. But H2 has vey low density, so the aircraft is bound to have a lot of dry weight and drag. Being non-RF yours is exempt from these problems

To answer the question, usually AJE users have difficult time with not enough thrust, instead of "thrust no problem". When you feel that, don't climb so fast as peopled are used to do with stock, level out or make a shallow dive if you have to.

[jrandom]

I find it funny that building an SR-71-style plane in KSP w/ AJE and RealFuels is how I figured out how to fly the realistically-modeled one in X-Plane -- have to flatten out at 10km and build up speed before climbing up to cruising altitude.