Ksp 2 Exhaust and jet engine. I hope!

[mcwaffles2003]

2 hours ago, Bingleberry said:

For those saying it’ll be “too complex” ignore that there are solutions for this... first, they can set the option in an “advanced tweakables” section, and let those that care about it to activate it.

So 2 different sets of gameplay parts based on the options menu? I just don't see that happening.

2 hours ago, Bingleberry said:

Also, somebody said “leave it to the modders,” that seems unreasonable to those of us that play console and can’t get any mods... I would love to see advanced life support.

Hopping that KSP2 incorporates the modding scene a bit better and they can find a way to use them with consoles.

 

4 hours ago, SpaceFace545 said:

One, two, three, my 16 month old cousin could remember each one.

4 hours ago, SpaceFace545 said:

also why do we need to focus on noobies and their feelings?

It's a bit weird that the guy who thought you can't see the milky way in space is the one with the dismissive elitist attitude

[Bingleberry]

3 hours ago, mcwaffles2003 said:

So 2 different sets of gameplay parts based on the options menu? I just don't see that happening

I don’t know, everybody in this forum rags on simplerockets, and even the tablet version gives you propellant options... I mean, if the kerbals are going to be capable of interstellar travel, shouldn’t they be able to optimize fuels for Eve-ASL flight?

[shdwlrd]

9 hours ago, SpaceFace545 said:

One, two, three, my 16 month old cousin could remember each one. Not complex if you’re having problems with your engine not working, maybe it’s cause you put methane in a jet engine. I just don’t know how you guys think three New fuels is complex. With the new future engines we will need, nuclear pulse devices, liquid hydrogen, helium 3, deuterium, metallic hydrogen, and fusion and fission pellets. So at that state with 6 new resources Adding 3 to it isn’t that much.

I was thinking of a good response to this, but Dstaal has already summed it up quite well.

16 hours ago, harrisjosh2711 said:

does it confuse you guys that there's a mono engine or xenon engine?

It does confuse me from time to time. If the motor doesn't call out the fuel type in the description, I'll assume its LFO. Most of the time I'm looking at DV and TWR values, not the type of fuels used.

Also it's true that people don't read instructions and dismiss pop-ups without reading them. Its a case of "get out of my way, I'm trying to do something here." That's why you don't see real instruction manuals with most consumer products anymore. We just expect them to work the way we think they should work.

[SpaceFace545]

58 minutes ago, shdwlrd said:

It does confuse me from time to time. If the motor doesn't call out the fuel type in the description, I'll assume its LFO. Most of the time I'm looking at DV and TWR values, not the type of fuels used.

I feel sorry for you

[shdwlrd]

1 hour ago, SpaceFace545 said:

I feel sorry for you

Why do you say that? 

[SpaceFace545]

Just now, shdwlrd said:

Why do you say that? 

cause you forget which engine uses which fuel.

[shdwlrd]

8 minutes ago, SpaceFace545 said:

cause you forget which engine uses which fuel.

Hmm... if that is what you want to go with, more power to you. 

[SpaceFace545]

24 minutes ago, shdwlrd said:

Hmm... if that is what you want to go with, more power to you. 

No not really I’m just kind of tired of this argument, it’s kind of stupid. The devs will do what the devs do and we just have to be fine with that wether they change liquid fuel or not the modders will.

[shdwlrd]

1 hour ago, SpaceFace545 said:

No not really I’m just kind of tired of this argument, it’s kind of stupid. The devs will do what the devs do and we just have to be fine with that wether they change liquid fuel or not the modders will.

I agree. Let the devs figure it out.

[Ethan Ng]

I think ksp2 should add rotating detonation engine.

The specifics impulse of the rotating detonation engine is 25% higher that the normal engine with it's fuel types.

[shdwlrd]

1 hour ago, Ethan Ng said:

I think ksp2 should add rotating detonation engine.

The specifics impulse of the rotating detonation engine is 25% higher that the normal engine with it's fuel types.

Since it's the same basic idea as the Orion drive, I can't see a reason not to add it at some point.

[Defenestrator47]

I don't post often, but I do in support of airplane stuff.  I love building rockets AND airplanes, and I'd love to see airplane parts fleshed out with more hull forms, engine types (propellers and ducted fans as STOCK was a huge yes), landing gear types (side drop, drop and rotate like some really old designs, etc.) and even 'here's a landing gear mount.  Now, how many wheels come out?' sort of procedural.  I want more procedural stuff in general.

Also, functional 'hold altitude/heading' autopilot, so I can sip my coffee comfily while I do a science bombing mission transit, and other fun things.

Lastly, as the non-gameplay trailer showed, I want more options for ground vehicles too.  I want a dozen different wheel types, good at different modes.  I want configurable cockpits.

If this stuff isn't stock, then I'll turn to mods, as there's a bunch out there that do a great job fleshing out the atmo side of KSP.

[KerikBalm]

On 5/14/2020 at 4:55 PM, shdwlrd said:

Since it's the same basic idea as the Orion drive, I can't see a reason not to add it at some point.

No, its not the same basic idea.

And 25% higher Isp is way too much.

It could lose less to atmosphere, but in the end all it achieves is a higher compression ratio, and should not change vacuum Isp with an optimal nozzle.

I'd give such qn engine a twr or atm Isp perk, not a flat +25% Isp boost

[shdwlrd]

11 hours ago, KerikBalm said:

No, its not the same basic idea.

So detonating liquid fuels to push the craft forward can't be the same concept as detonating an explosive to push a craft forward? Both are using a pressure front/wave to push the craft around. Yes, there is a marked difference in the strength of the pressure wave, but both are using the exact same concept.

 

11 hours ago, KerikBalm said:

And 25% higher Isp is way too much.

It could lose less to atmosphere, but in the end all it achieves is a higher compression ratio, and should not change vacuum Isp with an optimal nozzle.

I'd give such qn engine a twr or atm Isp perk, not a flat +25% Isp boost

Did you work on any of the projects? Do you know someone who is working on the project? Did you read the papers published on the project? As far as I know, rotating detonation propulsion hasn't made it out on the lab and all numbers are hypothetical. Much like all the numbers for the Orion drive. The Orion drive has never been built. So how do we know for certain what the actual numbers are?

PS. Have you ever seen the pressure wave from a FAE? It rivals that from plastic explosives. Look up fuel/air explosives and you will see what I mean.

[mcwaffles2003]

4 hours ago, shdwlrd said:

So detonating liquid fuels to push the craft forward can't be the same concept as detonating an explosive to push a craft forward? Both are using a pressure front/wave to push the craft around. Yes, there is a marked difference in the strength of the pressure wave, but both are using the exact same concept.

Rotating detonation engines, as we all saw in the recent Scott Manley vid, offers a continuous and constant acceleration in comparison to the Orion drives pulsing acceleration. If the contention is on the term "detonation" then we may as well say car engines run on the same concept as ICE engines allow cars to ride a pressure was and convert linear motion into rotational motion propelling them as well

[shdwlrd]

4 hours ago, mcwaffles2003 said:

If the contention is on the term "detonation" then we may as well say car engines run on the same concept as ICE engines allow cars to ride a pressure was and convert linear motion into rotational motion propelling them as well

Ok, I'm confused? What types of engines are you trying to compare? ICE is an acronym for internal combustion engine that encompasses "all" piston and gas turbine engines.

 

[mcwaffles2003]

Just now, shdwlrd said:

Ok, I'm confused? What types of engines are you trying to compare? ICE is an acronym for internal combustion engine that encompasses "all" piston and gas turbine engines.

 

That's the engine I meant

9 hours ago, shdwlrd said:

So detonating liquid fuels to push the craft forward can't be the same concept as detonating an explosive to push a craft forward? Both are using a pressure front/wave to push the craft around.

An internal combustion engine also utilizes a detonation to move a piston with its pressure wave front that inevitably turns a wheel to push the craft (car) forward. So using this logic you can't make much distinction between engines.

My point was an Orion drive works on explosive pulses pushing a craft forward in pulses where as a rotating detonation engine has continuous acceleration and is much more akin to pretty much every engine except an Orion drive

CFD video of a rotational detonation engine:

Spoiler

 

Exhaust is coming out of the top and fuel/ox is added through the bottom

[mcwaffles2003]

21 hours ago, KerikBalm said:

It could lose less to atmosphere, but in the end all it achieves is a higher compression ratio, and should not change vacuum Isp with an optimal nozzle.

If the exhaust is moving at supersonic speeds, since the exhaust is the product of a detonation,  then the exhaust velocities of rotating detonation engines should be higher than those of normal rocket engines where the exhaust flow is subsonic (except where shock diamonds appear).

Or am I missing something? Cause as I understand it in normal chemical rockets pressure is generated in the combustion chamber and then the contents are expelled along a pressure gradient out the nozzle which is a process that cannot exceed the speed of sound.

[shdwlrd]

1 hour ago, mcwaffles2003 said:

That's the engine I meant

An internal combustion engine also utilizes a detonation to move a piston with its pressure wave front that inevitably turns a wheel to push the craft (car) forward. So using this logic you can't make much distinction between engines.

My point was an Orion drive works on explosive pulses pushing a craft forward in pulses where as a rotating detonation engine has continuous acceleration and is much more akin to pretty much every engine except an Orion drive

CFD video of a rotational detonation engine:

  Reveal hidden contents

 

Exhaust is coming out of the top and fuel/ox is added through the bottom

Ok, I see where you're coming from. My point is that if KSP2 is going to use a Orion drive, the developers would have to program a delay into the thrust profile. Instead of using a long delay and a massive amount of thrust, they can use a very short delay and little thrust. In real life, they are both completely different concepts. But in game mechanics, they can be produced using the same techniques. 

I know what Nate said about the bomblets with the Orion drive, but there are ways to fudge the destructive effects and thrust generated in game. 

[mcwaffles2003]

42 minutes ago, shdwlrd said:

Ok, I see where you're coming from. My point is that if KSP2 is going to use a Orion drive, the developers would have to program a delay into the thrust profile. Instead of using a long delay and a massive amount of thrust, they can use a very short delay and little thrust. In real life, they are both completely different concepts. But in game mechanics, they can be produced using the same techniques. 

I know what Nate said about the bomblets with the Orion drive, but there are ways to fudge the destructive effects and thrust generated in game. 

I think g forces will depend on vessel/pusher plate size

Initially upon absorbing the blast the pusher plate will move forward and compress the shock absorber, then the rest of the craft will move as the absorber re expands and that will be when the g-meter will move. Acceleration should go up then down based on a sine wave and if the bombs are timed right it will become a continuous sine wave. Large ship + small plate will probably have low amplitudes and vice versa... Will be up to us to strike the balance is my guess.

[KerikBalm]

5 hours ago, mcwaffles2003 said:

If the exhaust is moving at supersonic speeds, since the exhaust is the product of a detonation,  then the exhaust velocities of rotating detonation engines should be higher than those of normal rocket engines where the exhaust flow is subsonic (except where shock diamonds appear).

Or am I missing something? Cause as I understand it in normal chemical rockets pressure is generated in the combustion chamber and then the contents are expelled along a pressure gradient out the nozzle which is a process that cannot exceed the speed of sound.

https://en.wikipedia.org/wiki/Detonation

A detonation is "is a type of combustion involving a supersonic exothermic front accelerating through a medium that eventually drives a shock front propagating directly in front of it. "

The supersonic thing here is the combustion front. In either case, the pressure is generated by expanding gas, and the speed of the gas is related to the temperature and MW of the exhaust.

16 hours ago, shdwlrd said:

So detonating liquid fuels to push the craft forward can't be the same concept as detonating an explosive to push a craft forward? Both are using a pressure front/wave to push the craft around. Yes, there is a marked difference in the strength of the pressure wave, but both are using the exact same concept.

Sure, if you want to be very general... but I can then say an orion drive is the same concept as a propeller, because they push mass backwards to move something forward.

As to why I don't see this as the same concept:

#1) An orion drive uses a shaped charge explosive, this does not

#2) An orion drive has the explosive set off outside and well away from the craft, this has the "explosion" inside the craft

Also, please note that the definition of a detonation is a supersonic combustion front, and it doesn't really apply ot the case of a nuclear chain reaction (which is not combustion). So if you use the term "detonation" as a synonym with explosion, then the Orion drive involves a detonation, but then many engines  meet this general definition.

This specific engine invovles the more technical definition of detonation... a supersoinc combustion front, which does not apply to nuclear explosions.

So you compare an internal detonation to an external shaped charge explosion... not all that similar.

Quote

Did you work on any of the projects? Do you know someone who is working on the project? Did you read the papers published on the project? As far as I know, rotating detonation propulsion hasn't made it out on the lab and all numbers are hypothetical. Much like all the numbers for the Orion drive. The Orion drive has never been built. So how do we know for certain what the actual numbers are?

Its still a chemical reaction, for which the energy of the reaction is well known. The theoretical maximum Isps from such reactions are well known. Given that we known that our engines get much more than 80% of the way towards the maximum possible Isp from such chemical reactions, there isn't room for a 25% improvement. To have such an improvement would be to create a free-energy device/to violate the conservation of energy.

[mcwaffles2003]

56 minutes ago, KerikBalm said:

https://en.wikipedia.org/wiki/Detonation

A detonation is "is a type of combustion involving a supersonic exothermic front accelerating through a medium that eventually drives a shock front propagating directly in front of it. "

The supersonic thing here is the combustion front. In either case, the pressure is generated by expanding gas, and the speed of the gas is related to the temperature and MW of the exhaust.

Looking into this further I've found the added efficiency is supposedly derived from the different types of engine cycles Rotating detonation engines (RDE's) undergo vs conventional chemical rockets.

Conventional rockets utilize the cycle referenced here specifically in fig 10.40 which is similar to the brayton cycle. Where as RDE's supposedly should benefit is from the detonation of the fuel mixture  as opposed to the conventional deflagration as the line 2-3 from the figure 10.40 (line 2 -3a in image below) should instead become vertical as in the Humphrey cycle (line 2-3 in image below) before expanding out the nozzle along 3-4:

Spoiler

The pressure in a detonations shock front, as I understand it, is greater than that of a deflagerated (I don't think this a word? Hopefully it communicates ideas as if it were  ) fuel which  allows more work to be extracted as the gas adiabatically expands

Edited May 17, 2020 by mcwaffles2003

[SciMan]

You can move the problem of "fuel-type realism" being confusing by making the fuel tanks capable of containing any fuel. Mods like B9PartSwitch and InterstellarFuelSwitch already do this, but that's only half the answer. The other half of the answer is to make it so that attaching an engine to a stage would automatically set the fuel type for those fuel tanks to the type that the engine uses. That would of course be tweakable later for those who use engines that use different fuel types on the same stage. But it would solve a lot of the problems of "I can't get this rocket to work" for first-time players.

That doesn't sound like something that's hard to code, it's literally just "ask the engine what kind of fuel it uses, then set 'these' (that stage's) tanks to contain that type of fuel".

This is a small bit of automation, but it's very handy. Half the time I spend building rockets when I'm playing with KSP Interstellar is spent cycling thru the fuel tank configurations to get the right one for the mission. And like I said, if you need to you could manually override it to get full control of what you want the rocket to carry (useful for things like fuel tankers that carry around an exotic fuel type but use a common fuel type for their engines).

[KerikBalm]

2 hours ago, mcwaffles2003 said:

Looking into this further I've found the added efficiency is supposedly derived from the different types of engine cycles Rotating detonation engines (RDE's) undergo vs conventional chemical rockets.

Conventional rockets utilize the cycle referenced here specifically in fig 10.40 which is similar to the brayton cycle. Where as RDE's supposedly should benefit is from the detonation of the fuel mixture  as opposed to the conventional deflagration as the line 2-3 from the figure 10.40 (line 2 -3a in image below) should instead become vertical as in the Humphrey cycle (line 2-3 in image below) before expanding out the nozzle along 3-4:

  Hide contents

The pressure in a detonations shock front, as I understand it, is greater than that of a deflagerated (I don't think this a word? Hopefully it communicates ideas as if it were  ) fuel which  allows more work to be extracted as the gas adiabatically expands

Yes, it can be a bit more efficient, but not 25% more Isp efficient. If there was still that much to be gained, they'd be using longer nozzles

[shdwlrd]

On 5/17/2020 at 9:53 AM, KerikBalm said:

Sure, if you want to be very general... but I can then say an orion drive is the same concept as a propeller, because they push mass backwards to move something forward.

Isn't the same concept, just using very different methods to achieve the same thing. Or does the laws of physics differ because one is using rotational motion to create thrust and the other is using an explosion?

On 5/17/2020 at 9:53 AM, KerikBalm said:

#1) An orion drive uses a shaped charge explosive, this does not

#2) An orion drive has the explosive set off outside and well away from the craft, this has the "explosion" inside the craft

Yes it did, some type of plastic explosive on the demonstrator back in the 50s. I'm pretty sure they didn't use mini nukes for a proof of concept. (I hope they didn't anyways.)

On 5/17/2020 at 9:53 AM, KerikBalm said:

Also, please note that the definition of a detonation is a supersonic combustion front, and it doesn't really apply ot the case of a nuclear chain reaction (which is not combustion).

Are both uncontrolled reactions? One in the atomic level and the other at the molecular level. In the end, the effect is the same, a release of energy and a pressure wave in atmosphere. Magnitudes of difference between the energy levels for the reactions I will admit.

On 5/17/2020 at 9:53 AM, KerikBalm said:

So if you use the term "detonation" as a synonym with explosion, then the Orion drive involves a detonation, but then many engines  meet this general definition.

Yes I am and that is true. The closest thing the orion drive relates to is a PDE.

On 5/17/2020 at 9:53 AM, KerikBalm said:

This specific engine invovles the more technical definition of detonation... a supersoinc combustion front, which does not apply to nuclear explosions.

So you compare an internal detonation to an external shaped charge explosion... not all that similar.

Please see above. The end effect is the same.

On 5/17/2020 at 9:53 AM, KerikBalm said:

Its still a chemical reaction, for which the energy of the reaction is well known. The theoretical maximum Isps from such reactions are well known. Given that we known that our engines get much more than 80% of the way towards the maximum possible Isp from such chemical reactions, there isn't room for a 25% improvement. To have such an improvement would be to create a free-energy device/to violate the conservation of energy.

Don't you think they would build that into their estimate?