The new, longer jet engine models

[Superfluous J]

So by Lego like are we talking 1980's Space Lego or modern day every set has at least one custom molded part like an Octopus?

Based on this I'd say the latter.

I should say, I voted "Don't care" but it's more like I don't mind but would prefer different. I like the idea of separate intakes, turbines, and nozzles. You could even do cool things like having 1 big turbine and 3 small nozzles. For... reasons.

But I prefer what was presented to nothing. I feel the turbines should be represented and any even semivalid one is better than none at all.

Edited November 5, 2015 by 5thHorseman

[paul23]

Why is the turbine looking as if it's a compressor?

In aircraft the turbine is typically quite small (especially for jet engines where it is sometimes almost omitted). It's the compressor that is the largest. - And the compressor is part of the air inlet, so if anything this part & corresponding mass increase should be part of the air inlets.

[ferram4]

Because the turbine is the compressor, people are simply identifying it incorrectly because that's how people are. As I understand it, the intake parts are intended less as "here is a hole and the compressor is right behind it" as on most planes and instead as "here is the opening to this duct that makes its way to the engine further down, like the S-duct on a 727 or the intakes on a modern fighter." In that context, especially given that the intake parts are almost never placed right where they should be if they're smacked right on the compressor with no ducting, the compressor portion should stay with the combustor and turbine that are attached to the nozzles that we're all used to seeing.

[pincushionman]

Because "turbine" has become a generic term referring to a jet engine, or more usually, a variant of a jet engine that extracts a large portion of the energy leaving the combustion chamber to produce work rather than thrust. Most jet engines nowadays don't produce thrust from the core exhaust; almost all of it is extracted to drive a fan (in a turbofan) or a shaft (in a turboshaft, turning a propeller, helicopter rotor, wheels, etc.). Most or all of the thrust is actually produced by these ancillary devices. So one could make the argument that the engine core is a turbine that produces work...even though that work usually drives a device that produces a jet for thrust.

The turbine itself is only a small part of the engine. You're right, the compressor is usually the biggest, heaviest part. Well, heaviest, at least. Modern fans can be pretty damn huge.

It's least confusing to just call these things "jet engines" in the context of KSP, because that's what they are (the thrust is a jet of air). However, remember that this style of engine should be called something different in different applications - you'd never call an Abrams tank engine a jet, since it produces next to no thrust, and everything goes into mechanical work. That would always be called a gas turbine instead.

Edited November 5, 2015 by pincushionman

[FleshJeb]

The turbine could be used to produce both exhaust power and torque. For example, the F-35 uses a drive shaft to power its lift fan:

This is a great opportunity to provide much more flexibility, gameplay and interesting design choices in KSP.

Instead of torque, just have it generate excess electricity if there are no active nozzles, or the active nozzles are not using all available power. It's a really simple solution.

Consider me solidly in the "Three-separate-parts" camp.

[EwingKang]

It's a little suprising that so many people against the terbine idea (mainly due to VTOL) to me. I really like the fine detail on that model and did feel excited.

For me togglable option is acceptable but probably not the best.

I would like to see two parts, one with the turbin+nozzle and one only nozzle. The one without terbine could be set to have smaller ISP and requires engine somewhere in the fuselage, just like the intake air thing. I think it is reasonable to have a turbine with nozzle have better performance than those need some manifold to pass the air.

[klgraham1013]

So by Lego like are we talking 1980's Space Lego or modern day every set has at least one custom molded part like an Octopus?

I'm 35. I know not of this octopus heresy you speak.

[Robje]

Perhaps it is me but i do not quite understand. Is this a visual improvement? How so if it is hidden within another part? And with this new model, the CoM is outside (or at least more caudal) of the nozzle?

[Castille7]

Adding more realism to the game is always a plus, that is why KSP is so fascinating. I am all for adding the turbines but please leave the option of the Engine parts as they are. I am also wondering if these would be attachable on the radial or only on the ends of the turbines? This would take away from realism but a space plane they would look nice with these mounted against the hull.

[Rath]

The com on jet engines has been outside for a while now.

[BlueCanary]

The com on jet engines has been outside for a while now.

Yeah, and other than a couple of bug reports until now nobody seems to have cared much. I don't see why its suddenlybsuch an important issue worth breaking tons of designs for.

[pizzaoverhead]

Instead of torque, just have it generate excess electricity if there are no active nozzles, or the active nozzles are not using all available power. It's a really simple solution.

Consider me solidly in the "Three-separate-parts" camp.

Ah, but if you have it generate torque, in addition to being able to run mechanical parts like propellers, fans, rotors and wheels, you can choose to add a generator to it and use it as a turboshaft to generate power just like an atmospheric fuel cell. It's more flexible that way.

- - - Updated - - -

Ah, but if you have it generate torque, in addition to being able to run mechanical parts like propellers, fans, rotors and wheels, you can choose to add a generator to it and use it as a turboshaft to generate power just like an atmospheric fuel cell. It's more flexible that way.

Because the turbine is the compressor, people are simply identifying it incorrectly because that's how people are. As I understand it, the intake parts are intended less as "here is a hole and the compressor is right behind it" as on most planes and instead as "here is the opening to this duct that makes its way to the engine further down, like the S-duct on a 727 or the intakes on a modern fighter." In that context, especially given that the intake parts are almost never placed right where they should be if they're smacked right on the compressor with no ducting, the compressor portion should stay with the combustor and turbine that are attached to the nozzles that we're all used to seeing.

If you were going to do it this way, the compressor would need to have a collider. You could set it up to have fairing-like coverings once a part is attached to it. You could still add RCS-like ducted nozzles alongside this, much like the Harrier, plus dedicated VTOL parts for those who like building that way.

[Birdco_Space]

I'm agnostically positive on the Turbine extension.

However, a l'm also in the 3 part camp.

I think the current selection of Jet Engines should go into a Turbine part(with the exception of the Rapier) which generates the resource "exhaust gas", and there should be a nozzle part which takes exhaust gas and converts it into thrust. There can be varieties of these nozzles that vary the amount of thrust/exhaust gas, weight, gimbal, mounting (inline or radial) to provide design variety. (I.e tiltable axial nozzles would suffer an weight and efficiency penalty over a inline/ non vectoring nozzle)

This method could provide flexibility to allow VTOL designers broader opportunity with a few more parts, while addressing the unrealism the dev were trying to address with the COM shift and the 1.5 change

Rapier is complex enough it should be a larger combined turbine/nozzle

[paul23]

Because "turbine" has become a generic term referring to a jet engine, or more usually, a variant of a jet engine that extracts a large portion of the energy leaving the combustion chamber to produce work rather than thrust. Most jet engines nowadays don't produce thrust from the core exhaust; almost all of it is extracted to drive a fan (in a turbofan) or a shaft (in a turboshaft, turning a propeller, helicopter rotor, wheels, etc.). Most or all of the thrust is actually produced by these ancillary devices. So one could make the argument that the engine core is a turbine that produces work...even though that work usually drives a device that produces a jet for thrust.

The turbine itself is only a small part of the engine. You're right, the compressor is usually the biggest, heaviest part. Well, heaviest, at least. Modern fans can be pretty damn huge.

It's least confusing to just call these things "jet engines" in the context of KSP, because that's what they are (the thrust is a jet of air). However, remember that this style of engine should be called something different in different applications - you'd never call an Abrams tank engine a jet, since it produces next to no thrust, and everything goes into mechanical work. That would always be called a gas turbine instead.

Then my question/remark still stands: this should be part of the air inlet. As the compressor is part of the air inlet, and if you look at any P-V or T-s diagram you'll notice that they serve exactly the "same" purpose. (Ok inlet is also responsible for lowering the airspeed to subsonic, but mostly it's just a matter of increasing the pressure of the air).

An explanations of the station numbers. It also gives a generic idea of how the sizes compare to each other. - The turbine is typically 2-4 rotators and also 2-4 stators. While the compressor can have as many as 20 stator-rotator combinations.

in turbofans there are actually two compressors: an low pressure which compresses part of the air, most of this air won't enter the combustion chamber. The high pressure compresssor only compresses the air that goes into the turbine. - These have also a larger turbine, as a lot of airspeed is gained by the first compressor, which has to be powered. - There is about 8-10 as much air that flows only through the low pressure compressor than air that enters the combustion chamber

On the other hand, tubojets typically have very little to no turbine: the movement is a direct consequence to the air speeding up in the nozzle. The turbine only has to power the main compressor.

Anyway, to show why the compressor is consider part of the inlet, look at an ideal T-S diagram (height 4-5 is by definition the same size as 2-3, so power you can use for propulsion is based on distance 5-7):

Quite frankly: an inlet in itself is really, really small. - Depending on the airspeed it's size is from a few cm to half a meter. But it's just a small metal strip, maybe with a small wing profile. - The compressor should really be part of that, as inlet + compressor type decides how much air will be scooped. Not only inlet. - A RAM inlet doesn't even have a compressor.

[cantab]

Yeah, and other than a couple of bug reports until now nobody seems to have cared much. I don't see why its suddenlybsuch an important issue worth breaking tons of designs for.

The very fact that Squad are fending off bug reports for something they did on purpose makes it an issue.

[DaJay42]

I'm pretty abivalent about the new models.

However, the 3-part setup some proposed sounds like it would open quite a few interesting possibilities.

[klgraham1013]

Yeah, and other than a couple of bug reports until now nobody seems to have cared much. I don't see why its suddenlybsuch an important issue worth breaking tons of designs for.

Because it's invisible mass. Anything that eliminates confusion for new players is a good thing.

- - - Updated - - -

The more I think on it, the more this picture from pizzaoverhead intrigues me:

By simply adding an "engine" part to the "nozzle" and "intakes" we have now, it creates a world of possibilities. It could even work as intakes do now, and not necessarily need the parts in a realistic order. This would allow the "game" crowd to be as flexible as they want, and the "realism" crowd to set their own limitations.

Prop - Engine

Nozzle - Engine - Intake

Generator - Engine - Intake

There's some interesting opportunities there.

Edited November 5, 2015 by klgraham1013

[SpaceplaneAddict]

Didn't they say the turbine would flip into other parts? Wouldn't that make it almost entirely visual?

[Pthigrivi]

The three part setup does create some balancing challenges. How many turbines do we need? What stats are balanced between the nozzles and the turbines?

[klgraham1013]

I would say, for simplicity's sake, have the "turbine" pull in intake air and create power, exhaust, or some such. The prop, nozzle, etc. would pull power and do it's thing. It would be irrelevant how much of one part you had compared to another. The part would just grab what was there, as engines do with intake air now.

As a standard, I would say 1 turbine could supply 1 jet engine of the same size at optimal usage.

[Capt Snuggler]

I'm not bothered by the new clipped turbine extension. Jet engines always seemed a bit "magical" *prepares fire extinguisher*

I, myself am guilty of building a few magical exploity craft and I'm always glad to have to redesign them. (v1.0 argument aside, the game is not complete)

BUT

I think pizzaoverhead has proposed the best solution for turbines.

intake + turbine + nozzle

I think on its own the turbine part could be a high power electric generator that consumes fuel. we could also have a separate Ducted Fan part instead of the one-part Goliath engine. (I like the Goliath but I think its a bit of a waste having it as one part)

although it is a little more complicated (4+ parts needed for propulsion) I think in the long term people will get over it and ultimately build more interesting stuff.

-----edit------

I would say, for simplicity's sake, have the "turbine" pull in intake air and create power, exhaust, or some such. The prop, nozzle, etc. would pull power and do it's thing. It would be irrelevant how much of one part you had compared to another. The part would just grab what was there, as engines do with intake air now.

As a standard, I would say 1 turbine could supply 1 jet engine of the same size at optimal usage.

Yup this is good. allows people to put the turbines where and how they want to.

1 intake + 1 turbine + 2 nozzle = 50% power per nozzle.

2 intakes + 2 turbine + 1 nozzle = 200% power but excessive heat at the nozzle.

props and ducted fans could function as an intake and a high efficiency thruster in one, but only suitable for lower altitudes.

Edited November 5, 2015 by Capt Snuggler

[paul23]

I'm not bothered by the new clipped turbine extension. Jet engines always seemed a bit "magical" *prepares fire extinguisher*

I, myself am guilty of building a few magical exploity craft and I'm always glad to have to redesign them. (v1.0 argument aside, the game is not complete)

BUT

I think pizzaoverhead has proposed the best solution for turbines.

intake + turbine + nozzle

I think on its own the turbine part could be a high power electric generator that consumes fuel. we could also have a separate Ducted Fan part instead of the one-part Goliath engine. (I like the Goliath but I think its a bit of a waste having it as one part)

although it is a little more complicated (4+ parts needed for propulsion) I think in the long term people will get over it and ultimately build more interesting stuff.

An intake IS a compressor. There is NOTHING else to an intake than a compressor, and the only goal of the intake other than housing the compressor is to make the airstream not stall before the turbine - but that's often not necessary.

If you wish to name it anything, name the "turbine" the "engine". The three parts together: "compressor, combustion chamber & turbine" are the engine. The rest is all streamlining an making the air flow the correct way.

A three part is also simple, just look at what the engine does:

- It takes a mass flow of air (as provided by the inlet)

- It outputs a mass flow of hot air at zero speed. (Or actually next to zero, but the deviation is of the similar order of magnitude as not using an N-body problem). And some extra electrical power for equipment.

- The nozzle converts this hot air to fast-air.

So basically you have one extra material flowing around: heated-air. Please also don't start calling it power or something, the engine doesn't provide that in aviation.

Actually this then could be extended/abstracted to any engine:

-You have the part that provides fuel & oxidizor (Using a compressor for air-breathing, and a pumping system for non air breathing)

-Followed by a combustion chamber

-And finally you have a nozzle. (Which is either convergent, or convergent-divergent in supersonic exhaust speeds).

One could also add this to liquid engines, or -combining the first two- to a solid propellant rocket. The nozzle is exactly the same whether you would use airbreathing or not, the difference is dependent on the temperature of the propellant. (Rocket engines typically heat up the propellant much more, so the nozzle becomes choked more easily).

Edited November 5, 2015 by paul23

[cantab]

No, an intake is a hole for air to go in. It's clearest on some early jet fighters like the F-86 Sabre, where the intake is at the nose of the aircraft but the turbine is some way back behind the cockpit. The two are of course linked by an air duct, which is abstracted away in KSP just like we don't have worry about fuel pipes or electrical cables.

Edit: The compressor is way back too. Basically all the spinny mechanical bits of the engine are close together, except for the shaft and whatever it drives in turboshaft (and in principle turboprop) engines. The air intake can be some distance away and is pretty much just a shaped opening for air. The jet nozzle can also be at a distance and again is a shaped opening for hot gas (well, ignoring afterburners), though that does reduce efficiency and performance.

Edited November 5, 2015 by cantab

[Majorjim!]

Intake and exhaust are a perfect way to do it, It makes perfect sense. There are plenty of things in the game that new players will find confusing, in fact that excuse for this monstrosity is very poor indeed. Yup, you're buying the beer tonight Snuggler.

All this does is add a useless part. Squad wont make it a turbine generator chaps so it's moot.

[paul23]

No, an intake is a hole for air to go in. It's clearest on some early jet fighters like the F-86 Sabre, where the intake is at the nose of the aircraft but the turbine is some way back behind the cockpit. The two are of course linked by an air duct, which is abstracted away in KSP just like we don't have worry about fuel pipes or electrical cables.

Well yes - but the graphics of the intakes in the game really show they also are part of the compressor. - And an intake is in basics just that: a hole. A hole doesn't have extra mass.