Never say never, but I think It works well using chamber pressure for nuclear thermals. The H2O nuclear thermal has the highest density impulse in the game currently, so it has an interesting advantage over the LH2 at the same chamber pressure. If a player were so inclined, they could certainly XML mod the engine and increase chamber pressure to match thrust power. @Gregrox
Thanks for letting me know. I've been hacking all around that code in this update so I've obviously messed it up. I submitted a bug report so we won't lose track of it.
@Gregrox Thank you for the clarification. I'm afraid that our comment character limit may have cut off some of your comment. Sorry about that!
It is a really interesting way to compare the engine types. You would be correct that it would violate the laws of thermodynamics if we claimed both engines had the same power, but they clearly do not. Looking at the Thrust Power equation, I don't see how mdot could be constant between the two.
P = 1/2 * T * Ve P = 1/2 * Isp * mdot * g0 * Ve or P = 1/2 * mdot * Ve^2
If Isp and Ve decrease then mdot would need to increase to give equivalent power. The player can increase mdot by increasing the throat radius of the engine and/or increasing chamber pressure.
We are approaching things a bit differently. Instead of holding power constant between fuel types, we hold chamber pressure constant and calculate everything else from that. This allows us to calculate exit pressure dynamically from their nozzle parameters (edit: and update Isp) as the player moves through an atmosphere.
@Gregrox The molecular weight is higher for H2O vs LH2, which results in higher mass flow, but slower exhaust velocity and gives about the same thrust between the two propellants. Without changing chamber pressure or the throat radius it doesn't affect thrust. Water does have the advantage of much higher density impulse. We had some more discussion about this on your suggestion post. Let me know if you find any flaws in my thinking. I appreciate your feedback.
I tweaked the masses and prices of the rocket engines quite a bit with this update. I think they should be a lot more reasonable now and react a bit more realistically to the settings (ie - no more negative masses). Let me know if you see any odd cases.
@SupremeDorian We ran into some technical snags with SimpleWheels 4D. We just don't have the technology available yet to make it a reality. Hopefully, someday we can do it. It will be our Avatar.
@pedro16797 @AnotherFireFox That is a really clever idea using the RCS thrust as an input to an engine. For the multi-directional RCS part we could either do a block with several nozzles (probably 5) or a single nozzle that can rotate on a ball joint that can direct its thrust (nearly) anywhere in a hemisphere, like this thing. That part won't make it in this update, so we still have more time to think about it and you have more time to influence its development.
@pedro16797 @AnotherFireFox I'll look into scaling a bit smaller for the next beta update. I think you also need a setting to enable RCS style control for any rocket engine.....I'll have to think about that one.
9 and 10: Good ideas, but not sure we will have enough time to make it happen.
11: I'm sure you already know this, but the Mach setting in the PA window currently only affects jet engines. If the aerospike thrust drop at Mach 3-5 is implemented, then it would make sense to do this.
12: The thrust equations take the fuel properties into account when calculating thrust, so they should be accurate given the propellant type.
Thrust = MassFlow * ExhaustVelocity
Hydrolox and Methalox have lower molecular weights than Kerolox so mass flow (for a given throat area) drops, but exhaust velocity increases resulting in about the same thrust. Chamber pressure and throat area are the biggest driving factors behind thrust. The big advantage of the water propellant type is the massive increase in density impulse.
13: We won't have time to add another engine type at this time.
14: I can look into it. This was my attempt to slightly nerf the engines.
15: I will look into it.
16: I agree this needs to be improved. I'd like the PA window to work a little better with staging and allow selecting different planets so you can see DeltaV in totally different environments.
17: Good catch. Thanks.
18: It's a good idea. Maybe negative changes could be highlighted in red and advantageous changes could be highlighted in blue. I'll keep it in mind, but can't make any promises.
@pedro16797 @Kell Thanks for the feedback guys. I will revisit the mass calculations next week. We intend to keep this version in beta for longer than usual because and we've had some significant changes and we thought we might get a lot more feedback.
@pedro16797 The supportsWarpBurn is really for the lower power ion engines. I just need to disable warp mode while SRBs are active. Thanks for the screenshots.
(1) This is something I struggle with because while it is easy to launch stuff into orbit now (just crank the engine size and throat size up), the Isp's for these engines are already somewhat lower than in real life. WIth sandbox mode, there's not a lot of challenge. Campaign mode will help in this regard and bring the challenge back as the player has to earn those more powerful engines.
(2) and (3) Can you provide some examples and what you think their mass should be? I've been tweaking these numbers for so long now and it's a very difficult balancing act. More data points would be helpful.
(4) Good catch. Thanks!
(5) Ya, but they look so much cooler :D
(6) and (7) Shock diamonds would look cool, I agree. I ran out of time for now. Maybe later. Cone shaped plumes look terrible, but maybe I can try turning those on for the next update.
@SupremeDorian It's useful in case you get really thirsty in space. Also, the nuclear thermal engine can break it down into hydrogen and oxygen and then combust it, which gives great specific impulse and great density impulse. You can thank @Gregrox for that idea,
@pedro16797 The throat radius doesn't have a visual representation, but it is a way to let the player tweak the nozzle ratio. Regarding the aerospike on solid rocket motors, there is at least one case of it being done.
I'm really sorry about the interruption yesterday. Our service provider was (obviously) having some issues. I was going to wait to hear back from them before responding, but they haven't responded to my support ticket yet. It does appear that we have lost data from yesterday. It is highly doubtful that it will be recoverable, but I will let you know if they are able to recover any of it.
Thanks @mjdfx150529. You have some good ideas in there. I'm not sure when we will start on tech trees or campaign mode, but it is good to bounce some ideas around.
@pedro16797 @Gregrox Thanks for letting me know about the cone shape. I wasn't aware of that. I do plan to experiment with different colors based on the fuel type.
@AnotherFireFox @mjdfx150529 @pedro16797 This is a more accurate representation of the overexpansion at sea level. And here's about the max under-expansion currently possible.
@bartekkru100 You are right the exhaust should be more streamlined. It actually should be a bit overexpanded as its exit pressure is lower than ambient. We'll get The under-expanded state definitely looks better with our current visuals, IMO, so that's why I chose it for this teaser.
@mjdfx150529 @bartekkru100 Players are so astute in this community! This engine is using the theoretical max for thrust, mass flow, etc and of course, that would not be attainable in the real world. One of the final steps of this project will be applying some level of realism to knock down the Isps to a more reasonable level (ie - not 100% efficient).
@Kell I could be swayed.
5.5 years ago@Shoot2kill We are hoping to have landing gear in the next update.
+3 5.5 years agoNever say never, but I think It works well using chamber pressure for nuclear thermals. The H2O nuclear thermal has the highest density impulse in the game currently, so it has an interesting advantage over the LH2 at the same chamber pressure. If a player were so inclined, they could certainly XML mod the engine and increase chamber pressure to match thrust power. @Gregrox
+1 5.5 years agoCan you give us a screenshot of what you are seeing in the game?
5.5 years ago@Kell The Isps changed slightly with the change in how efficiency was applied, so I took the opportunity to nerf them just slightly more.
+4 5.5 years ago@JoeJoeFlies What version of Windows are you using? Or are you on Mac? You can also try here:
5.5 years ago%APPDATA%\..\LocalLow\Jundroo\SimpleRockets 2\output_log.txtCan you send us your log file to games@jundroo.com? You can find it here (assuming Windows):
+1 5.5 years ago%userprofile%\appdata\locallow\Jundroo\SimpleRockets 2\output_log.txtThanks for letting me know. I've been hacking all around that code in this update so I've obviously messed it up. I submitted a bug report so we won't lose track of it.
5.5 years ago@MarioG No plans for such things, but it would be super easy for a mod to add those fuel types.
+3 5.5 years ago@Gregrox Thank you for the clarification. I'm afraid that our comment character limit may have cut off some of your comment. Sorry about that!
It is a really interesting way to compare the engine types. You would be correct that it would violate the laws of thermodynamics if we claimed both engines had the same power, but they clearly do not. Looking at the Thrust Power equation, I don't see how mdot could be constant between the two.
P = 1/2 * T * VeP = 1/2 * Isp * mdot * g0 * VeorP = 1/2 * mdot * Ve^2If Isp and Ve decrease then mdot would need to increase to give equivalent power. The player can increase mdot by increasing the throat radius of the engine and/or increasing chamber pressure.
We are approaching things a bit differently. Instead of holding power constant between fuel types, we hold chamber pressure constant and calculate everything else from that. This allows us to calculate exit pressure dynamically from their nozzle parameters (edit: and update Isp) as the player moves through an atmosphere.
+1 5.5 years ago@Gregrox The molecular weight is higher for H2O vs LH2, which results in higher mass flow, but slower exhaust velocity and gives about the same thrust between the two propellants. Without changing chamber pressure or the throat radius it doesn't affect thrust. Water does have the advantage of much higher density impulse. We had some more discussion about this on your suggestion post. Let me know if you find any flaws in my thinking. I appreciate your feedback.
+1 5.5 years ago@Gregrox Which rocket engine type and power cycle?
5.5 years ago@pedro16797 Thanks for letting us know. We'll try and get it fixed as soon as we can.
+4 5.5 years agoThe bell, cone, and delta nozzle extension are incorrectly textured. They will be fixed next week.
+2 5.5 years agoI tweaked the masses and prices of the rocket engines quite a bit with this update. I think they should be a lot more reasonable now and react a bit more realistically to the settings (ie - no more negative masses). Let me know if you see any odd cases.
+1 5.5 years ago@Bmcclory No news to report yet on SimpleTrees, but I am excited to dig into the science behind tree physiology!
+4 5.5 years ago@SupremeDorian We ran into some technical snags with SimpleWheels 4D. We just don't have the technology available yet to make it a reality. Hopefully, someday we can do it. It will be our Avatar.
+4 5.5 years ago@pedro16797 Make a suggestion post (if you haven't already) and we'll see what we can do :)
+2 5.5 years ago@pedro16797 @AnotherFireFox That is a really clever idea using the RCS thrust as an input to an engine. For the multi-directional RCS part we could either do a block with several nozzles (probably 5) or a single nozzle that can rotate on a ball joint that can direct its thrust (nearly) anywhere in a hemisphere, like this thing. That part won't make it in this update, so we still have more time to think about it and you have more time to influence its development.
+2 5.5 years ago@Kell :D
+1 5.5 years ago@Kell The mass flow actually goes up quite a bit with H2O but the exhaust velocity goes down, so the thrust is the same.
+3 5.5 years ago@pedro16797 @AnotherFireFox I'll look into scaling a bit smaller for the next beta update. I think you also need a setting to enable RCS style control for any rocket engine.....I'll have to think about that one.
+3 5.5 years ago9 and 10: Good ideas, but not sure we will have enough time to make it happen.
11: I'm sure you already know this, but the Mach setting in the PA window currently only affects jet engines. If the aerospike thrust drop at Mach 3-5 is implemented, then it would make sense to do this.
12: The thrust equations take the fuel properties into account when calculating thrust, so they should be accurate given the propellant type.
Thrust = MassFlow * ExhaustVelocityHydrolox and Methalox have lower molecular weights than Kerolox so mass flow (for a given throat area) drops, but exhaust velocity increases resulting in about the same thrust. Chamber pressure and throat area are the biggest driving factors behind thrust. The big advantage of the water propellant type is the massive increase in density impulse.
13: We won't have time to add another engine type at this time.
14: I can look into it. This was my attempt to slightly nerf the engines.
15: I will look into it.
16: I agree this needs to be improved. I'd like the PA window to work a little better with staging and allow selecting different planets so you can see DeltaV in totally different environments.
17: Good catch. Thanks.
18: It's a good idea. Maybe negative changes could be highlighted in red and advantageous changes could be highlighted in blue. I'll keep it in mind, but can't make any promises.
+3 5.5 years ago@Kell 25 percent!? What are these?Engines for ants?
+5 5.5 years ago@SupremeDorian uncheck the option below the build mode and it won’t do that.
+1 5.5 years ago@pedro16797 Thanks for letting me know. I created a forum post here while the release post is not public yet.
+1 5.5 years ago@pedro16797 @Kell Thanks for the feedback guys. I will revisit the mass calculations next week. We intend to keep this version in beta for longer than usual because and we've had some significant changes and we thought we might get a lot more feedback.
+2 5.5 years ago@pedro16797 The supportsWarpBurn is really for the lower power ion engines. I just need to disable warp mode while SRBs are active. Thanks for the screenshots.
+2 5.5 years ago@pedro16797 Thanks for the feedback. What do you mean by the white outlayer?
5.5 years agoThanks for the feedback!
(1) This is something I struggle with because while it is easy to launch stuff into orbit now (just crank the engine size and throat size up), the Isp's for these engines are already somewhat lower than in real life. WIth sandbox mode, there's not a lot of challenge. Campaign mode will help in this regard and bring the challenge back as the player has to earn those more powerful engines.
(2) and (3) Can you provide some examples and what you think their mass should be? I've been tweaking these numbers for so long now and it's a very difficult balancing act. More data points would be helpful.
(4) Good catch. Thanks!
(5) Ya, but they look so much cooler :D
(6) and (7) Shock diamonds would look cool, I agree. I ran out of time for now. Maybe later. Cone shaped plumes look terrible, but maybe I can try turning those on for the next update.
+5 5.5 years ago@pedro16797 I'm not sure...where are you seeing it?
5.5 years ago@SupremeDorian It's useful in case you get really thirsty in space. Also, the nuclear thermal engine can break it down into hydrogen and oxygen and then combust it, which gives great specific impulse and great density impulse. You can thank @Gregrox for that idea,
+1 5.5 years ago@WNP78 lol, thanks! And yes, this is the real one.....I think.
+3 5.5 years ago@Kell If you find some funky configurations, please feel free to send in a bug report and I can investigate them.
+1 5.5 years ago@pedro16797 The throat radius doesn't have a visual representation, but it is a way to let the player tweak the nozzle ratio. Regarding the aerospike on solid rocket motors, there is at least one case of it being done.
+3 5.5 years agoWhy look for a neighbor? I live in one of their houses! What can I help you with?
+7 5.5 years ago@SupremeDorian SimpleWheels will rise again! We just need to get the ball rolling on it. The licorice idea....ya, I uh....I'll think about that one.
+8 5.5 years ago@mjdfx150529 Thanks. I created a bug report so we can make sure to address this at some point.
+2 5.5 years agoReally nice work!
+4 5.5 years agoA picture's worth a thousand words. @SupremeDorian
+7 5.5 years agoHa, whoops. Ya, copy-pasta.
+19 5.6 years agoI'm really sorry about the interruption yesterday. Our service provider was (obviously) having some issues. I was going to wait to hear back from them before responding, but they haven't responded to my support ticket yet. It does appear that we have lost data from yesterday. It is highly doubtful that it will be recoverable, but I will let you know if they are able to recover any of it.
+2 5.6 years agoThanks @mjdfx150529. You have some good ideas in there. I'm not sure when we will start on tech trees or campaign mode, but it is good to bounce some ideas around.
+1 5.6 years ago@pedro16797 @Gregrox Thanks for letting me know about the cone shape. I wasn't aware of that. I do plan to experiment with different colors based on the fuel type.
+3 5.6 years ago@AnotherFireFox @mjdfx150529 @pedro16797 This is a more accurate representation of the overexpansion at sea level. And here's about the max under-expansion currently possible.
+2 5.6 years ago@bartekkru100 You are right the exhaust should be more streamlined. It actually should be a bit overexpanded as its exit pressure is lower than ambient. We'll get The under-expanded state definitely looks better with our current visuals, IMO, so that's why I chose it for this teaser.
+4 5.6 years ago@mjdfx150529 @bartekkru100 Players are so astute in this community! This engine is using the theoretical max for thrust, mass flow, etc and of course, that would not be attainable in the real world. One of the final steps of this project will be applying some level of realism to knock down the Isps to a more reasonable level (ie - not 100% efficient).
+2 5.6 years ago@Bmcclory If I had to give this one a name, I'd probably go with SCORCH 1000.
+3 5.6 years ago@DonaldDuckje iOS release date is this year, but unfortunately, I can't be more specific yet.
+2 5.6 years ago@Mod lol, ya I haven't worked on actually calculating price or mass for the engines yet.
+3 5.6 years ago