Jet engine overhaul Discussion

[Rath]

I know this likely will not happen, but I want it to.

Separate Jet Engines and Nozzles:

This would change jet engine from being a two part system (Nozzle, Intake), to a Three part system.  To get a jet nozzle to function you would need an intake, engine/turbine (significantly smaller than the exhaust, but not fully one size smaller.  Still stays under 1.25m category if it fits a 1.25m exhaust for example) and a nozzle.  

 

 Intakes: The intake mainly governs the way air is taken into the engine.  The same as now, with two new parts, and separating of the Goliath into intake, bypass fan and the 1.25m low speed turbine and a goliath nozzle.

 

Add-ons: These are not required for the functioning of the engine, but help it do something or have a special effect.  These are mounted on a few different places in the engine.  E.G. Pre-coolers for increasing hypersonic performance by cooling down intake air,  High bypass intake attachments for massive efficiency boosts, or afterburners as a ASAS-thickness toggleable thrust booster.

 

Turbine: This mainly governs the thrust, Altitude and efficiency of the engine jointly with the exhaust.  These parts fit within special mounting parts, similar to the structural fuselage, but with thicker walls and they contain liquid fuel.  The engine nacelle becomes one of these parts. 2.5m version, 1.25m version and 2.5m and 1.25m engine nacelle.  There would be at least four parts for 1.25m, one low speed turbine (Wheesley), one middling one (Panther) and one hypersonic one (Whiplash), and one convertible to rocket one, that only works with the matching exhaust to fully function, but can rocket augment the other nozzles (RAPIER), basically a super powered afterburner that runs on oxidizer, but doesnt work without air.

 

Exhaust: Governs the Speed curve and, jointly with the turbine, the ISP.  These would use the current models we have now.  There would be four versions, corresponding with the turbines.  When set with the matching turbine, they produce the current values.

 

Possible Combination examples for 1.25m:

Turbine	Exhaust	Result
Wheesley	Wheesley	Normal Wheesley
Wheesley	Panther	low altitude-medium speed
Wheesley	Whiplash	low altitude-high speed
Wheesley	RAPIER	low altitude- high speed, with rocket agumentation.
Panther	Wheesley	medium altitude-low speed
Panther	Panther	Normal Panther
Panther	Whiplash	medium altitude-high speed
Panther	RAPIER	medium altitude, high speed with rocket agumentation
Whiplash	Wheesley	high altitude, low speed (This combination is what made me want to make this)
Whiplash	Panther	high altitude, medium speed
Whiplash	Whiplash	Normal Whiplash
Whiplash	RAPIER	normal whiplash with rocket agumetnation
RAPIER	Wheesley	a heavier whiplash-wheesley
RAPIER	Panther	a heavier whiplash-panther
RAPIER	Whiplash	a heavier normal whiplash
RAPIER	RAPIER	Normal RAPIER

 

Edited September 19, 2016 by Rath
Actually completing it

[temporalExile]

Interesting!

I actually thought about throwing together a mod that did this a long time ago, but it never saw the light of day, due to my lack of programming abilities beyond .CFG editing

[Capt Snuggler]

I posted something like this a while back.

I too would like air breathers to be a 3 part system. intake - compressor/turbine - nozzle. - with relevant weight adjustments.

the turbine could function on its own to generate large amounts of electric charge. you could bolt on a propeller and have turbo prop or ducted fan. you could also move the turbine forward to shift the centre of mass while keeping the nozzle at the rear.

lots of possibilities but sadly that ship has sailed. 

[Van Disaster]

This has been brought up a lot ( and there's a lot of details to consider ) over the years including a couple of months ago, and the first thing to consider is "why". The second thing to consider is how much it'd wreck gameplay ( currently you can put jets inside fuel tanks, effectively ) and whether that's desirable, and the last is "how".

KSP Engines are simple converters of resources to thrust - in that respect there's no difference between a propellor and a rocket other than some inertia in the throttle.

* What would be the function of your nozzle?
* What would be the function of your engine?

Ignore any implementation details.

Edited September 15, 2016 by Van Disaster

[Moarmau5]

Interesting idea. But like @Van Disaster noted, deep down, jet engines and rocket engines are essentially the same thing, apart from a few minor behavior and aesthetic details. 

So if jet engines are to be broken into individual parts, wouldn't rockets need these respective parts as well?

For example, to construct a jet, you need an intake, compressor/turbine, and a nozzle. To construct a rocket you need a turbopump, combustion chamber, and a nozzle. 

I would certainly play around with this set up if it was available. However, I feel this would be better suited as a mod rather than stock, given the added complexity and the amount of parts that would have to be added.

[Van Disaster]

I should point out that I'm actually in favour of splitting gas generators/any other engine from drive devices provided there's a decent torque transfer system implemented as well ( NOT some misuse of the current resource system, it's not sufficient ), so it makes turboshaft & multiple propulsion possible - imagine switching from wheels to water jets, for instance. Not only that, torque transfer would be useful for other things. The thing about basic turbojet/fan/props is what do you get out of splitting them into gas generators & thrust producers, over having it all in one part? especially now you can upgrade parts.

Mass distribution is somewhat solved by the CoM offset. The design issue that gas generators really should take a lot more space would already have been solved simply by making the existing parts much bigger, so that must have been an actual concious decision.

[Rath]

This wasn't actually meant to post yet.

[Jonfliesgoats]

I love this idea, but it leads us down a slippery slope.  For example, what about variable geometry compressors and stators?  Can we tweak those to make trade offs between engine acceleration v. Economy?  I would love to be able to control the number of turbine stages on an engine.  I would love to have some control of rocket nozzle/bell geometry.  I would love to be able to decide whether I can add an afterburner or save weight on various engines.  If you give people like me everything we want, you will have an unplayable game which focuses on metallurgy, optimization of fuel nozzles, etc.  Eventually, after several hours of design, you would actually fly your Kerbals with real, conservative and boring test protocols.  If everything goes well after many more hours of very conservative and careful flight testing, the Kerbals would issue new type certificate data sheets for your Kerbal craft.

This is why people like me must be stopped before it is too late.

I think the general suggestion here is a good one, but should be careful not to go too far. 

[Van Disaster]

@JonfliesgoatsIf you haven't, I suggest you give AJE a try - it won't split engines into components, but it does do a much better job of simulating actual jets.

[Jonfliesgoats]

I'd love to try it! 

6 hours ago, Van Disaster said:

@JonfliesgoatsIf you haven't, I suggest you give AJE a try - it won't split engines into components, but it does do a much better job of simulating actual jets.

 

[Wjolcz]

Not needed IMO. Complicating something that already works is never a good idea. Look what happened to the career.

Oh, wait... It never properly worked. We just got used to it.

[Rath]

Finished it actually.

[Rath]

On 9/16/2016 at 2:05 AM, Moarmau5 said:

Interesting idea. But like @Van Disaster noted, deep down, jet engines and rocket engines are essentially the same thing, apart from a few minor behavior and aesthetic details. 

So if jet engines are to be broken into individual parts, wouldn't rockets need these respective parts as well?

For example, to construct a jet, you need an intake, compressor/turbine, and a nozzle. To construct a rocket you need a turbopump, combustion chamber, and a nozzle. 

I would certainly play around with this set up if it was available. However, I feel this would be better suited as a mod rather than stock, given the added complexity and the amount of parts that would have to be added.

Well, for rockets, the combustion chamber, nozzle and other parts are specially built, whereas many aircraft (especially military) have diffrent shaped intakes and nozzles.  And, there is only four jets, giving us some serious restrictions on operation envelopes.

[Van Disaster]

Well, I looked at your table & from a realism point of view a lot of things don't make sense like the Panther & Whiplash nozzles being different, one is a C-D vectoring one and the other is a C-D less-vectoring one but they're both supersonic nozzles. Where's the work on intakes? they make a much bigger difference than nozzles. The only variables you want with nozzles are ( probably in this order ) "is it variable?  does it have an afterburner? does it vector?". If you're taking a core+fittings approach then where's the bypass "attachments" to make turbofans/turboprops? and lastly the RAPIER is not an attachment to a jet engine, it's a rocket which can use atmosphere as fuel. The low-tech version would be a ramrocket, which is a ramjet/rocket combination ( apparently more efficient than a straight-up ramjet thanks to higher compression ) - there's no "nozzle" that will turn a jet engine into a RAPIER.

From a gameplay point of view that's too many parts - you need a small turbine, a bigger turbine, and then a LACE ( the RAPIER ), and then upgrades to those - If I'm reading how the new upgrade system works you can handle everything you want to do by inserting engine options as upgrades.

If you're going to do all the hassle of a modular engine you need to do the *entire* system - intakes and placement included, so no more jet engine in the fuselage & air intakes at the wingtips. Also if you're going to bother then you want "a jet exhaust" with features & procedural editing, and to do the whole thing properly ala AJE so internal temperatures & cross-sections matter.

[Rath]

Ok, the post I made because I completed this didn't show up.  Stupid Forum on School Wi-fi.

 

I'm fine with the way the intakes and engines work right now, but it would be cool to have that as part of a spinoff game or expansion: Kerbal Aircraft Program.

 

I also think that this system would work very well for turboprops too.