MathiLpHD

Now that we know most stats of the Raptor engine, what do you think? Do you think there will be multiple versions of the Raptor like the Merlin engine? So that they increase the stats over time? And what are your estimations for the weight of the engine? I mean, the core has the same size as the Merlin engines core but the Raptor has a higher nozzle ratio so it shouldn't have MUCH more weight. The burning chamber will be heavier due to the 3 times higher pressure compared to the Merlin engine... I would estimate the weight to about 1,5* to 2*Merlin Engine so ~750kg to ~1000kg, maybe even more. But i think it should get over a TWR of 200 and i think it's highly possible that it has a TWR of 300 or even 400 (3050kN/(0,750t*10m/s^2) > 400).

@RA3236 It seems to be the same location (02000000) at each crash.

Hello! My RO/RSS/RP-0 install of KSP crashes pretty randomly with the error mono.dll caused an Access Violation. I installed nearly all my mods with CKAN. Modlist (over CMD): 26.03.2016 12:56 <DIR> . 26.03.2016 12:56 <DIR> .. 18.03.2016 22:13 <DIR> 000_FilterExtensions 18.03.2016 22:13 <DIR> 000_FilterExtensions Configs 18.03.2016 22:13 <DIR> 000_Toolbar 18.03.2016 22:13 <DIR> ActiveTextureManagement 18.03.2016 22:13 <DIR> AJE 18.03.2016 22:13 <DIR> AsteroidDay 20.03.2016 21:45 <DIR> B9_Aerospace 18.03.2016 22:13 <DIR> BobCatind 18.03.2016 22:13 <DIR> CommunityResourcePack 18.03.2016 22:13 <DIR> CommunityTechTree 21.03.2016 19:18 <DIR> ContractConfigurator 18.03.2016 22:13 <DIR> ContractPacks 18.03.2016 22:13 <DIR> CrossFeedEnabler 18.03.2016 22:13 <DIR> CustomBarnKit 18.03.2016 22:13 <DIR> DeadlyReentry 18.03.2016 22:13 <DIR> DMagicOrbitalScience 19.03.2016 17:22 <DIR> EngineGroupController 20.03.2016 20:55 <DIR> FASA 18.03.2016 22:13 <DIR> FerramAerospaceResearch 18.03.2016 22:13 <DIR> Firespitter 18.03.2016 22:13 <DIR> FreedomTex 18.03.2016 22:13 <DIR> FShangarExtender 24.03.2016 18:17 <DIR> InterstellarFuelSwitch 18.03.2016 22:13 <DIR> KAS 18.03.2016 22:13 <DIR> KerbalConstructionTime 26.03.2016 12:58 <DIR> KerbalEngineer 18.03.2016 22:13 <DIR> KerbalJointReinforcement 18.03.2016 22:13 <DIR> KIS 18.03.2016 22:13 <DIR> Kopernicus 18.03.2016 22:13 <DIR> KSCSwitcher 26.03.2016 12:58 <DIR> KSP-AVC 18.03.2016 22:13 <DIR> KWCommunityFixes 18.03.2016 22:13 <DIR> KWRocketry 26.03.2016 12:56 <DIR> MagicSmokeIndustries 18.03.2016 22:13 <DIR> MainSailor 18.03.2016 22:13 <DIR> MechJeb2 18.03.2016 22:13 <DIR> ModularFlightIntegrator 19.02.2016 20:24 62.976 ModuleManager.2.6.20.dll 26.03.2016 13:02 7.828.841 ModuleManager.ConfigCache 26.03.2016 13:02 470.909 ModuleManager.ConfigSHA 26.03.2016 13:02 6.616 ModuleManager.Physics 26.03.2016 13:02 71.075 ModuleManager.TechTree 18.03.2016 22:13 <DIR> ProceduralFairings 18.03.2016 22:13 <DIR> ProceduralFairings-ForEverything 18.03.2016 22:13 <DIR> ProceduralParts 18.03.2016 22:13 <DIR> RCSBuildAid 18.03.2016 22:13 <DIR> RealChute 18.03.2016 22:13 <DIR> RealFuels 18.03.2016 22:13 <DIR> RealHeat 19.03.2016 17:22 <DIR> RealismOverhaul 24.03.2016 20:07 <DIR> RealismOverhaul_GuidanceUnit 25.03.2016 18:54 <DIR> RealismOverhaul_RaptorEngine 18.03.2016 22:14 <DIR> RealPlume 18.03.2016 23:06 <DIR> RealSolarSystem 18.03.2016 22:14 <DIR> RemoteTech 18.03.2016 22:14 <DIR> RLA_Stockalike 19.03.2016 17:22 <DIR> RP-0 18.03.2016 22:14 <DIR> RSS-Textures 18.03.2016 22:14 <DIR> ScienceAlert 18.03.2016 22:14 <DIR> SmokeScreen 18.03.2016 22:14 <DIR> SolverEngines 18.03.2016 22:14 <DIR> SpaceXLegs 18.03.2016 22:14 <DIR> Squad 18.03.2016 22:14 <DIR> StageRecovery 20.03.2016 20:56 <DIR> StockBugFixPlus 20.03.2016 21:42 <DIR> StretchySNTextures 18.03.2016 22:14 <DIR> SXT 18.03.2016 22:14 <DIR> Taerobee 18.03.2016 22:14 <DIR> ThunderAerospace 26.03.2016 14:35 2.897 toolbar-settings.dat 25.03.2016 23:57 <DIR> TriggerTech 18.03.2016 22:14 <DIR> TweakScale 18.03.2016 22:14 <DIR> VenStockRevamp The main error message: Unity Player [version: Unity 4.6.4f1_99f88340878d] mono.dll caused an Access Violation (0xc0000005) in module mono.dll at 0023:1011940a. Error occurred at 2016-03-26_145838. D:\Program Files (x86)\Steamspiele(D)\steamapps\common\Kerbal Space Program\KSP.exe, run by Mathias. 44% memory in use. 0 MB physical memory [0 MB free]. 0 MB paging file [0 MB free]. 0 MB user address space [95 MB free]. Write to location 02000000 caused an access violation. Is this caused by KSP using to much memory? I am using DX11 and Active Texture Management Aggressive and got rid of useless parts with autopruner. I get ~2,49 GB of RAM used by KSP when loaded to the start screen.

Because you get higher thrust, lower stress on each turbine, higher isp and eventually higher thrust-to-weight-ratio. The russian solved the oxidation problem in the 60s or 70s and with using methane you won't have to deal with coking. Compared to a gas generator you should be able to get ~40s more impulse with FFSC and compared to a ORSC it gains ~10s. So it should be a pretty big improvement.

Well, as far as i know, they use active cathodic protection on cars. That should normally do it because active protection is better than passive protection. And if you have a look at https://en.wikipedia.org/wiki/Corrosion#High-temperature_corrosion: "The products of high-temperature corrosion can potentially be turned to the advantage of the engineer. The formation of oxides on stainless steels, for example, can provide a protective layer preventing further atmospheric attack, allowing for a material to be used for sustained periods at both room and high temperatures in hostile conditions. Such high-temperature corrosion products, in the form of compacted oxide layer glazes, prevent or reduce wear during high-temperature sliding contact of metallic (or metallic and ceramic) surfaces."

@shynung It doesn't need "exotic" materials, it just needs corrosive resistant materials. I don't know if the standard zinc-steel of a car is good enough but i am not an expert for corrosion. Because than you would have to use exotic materials for the turbine and still loose 10s of specific impulse because you need to power two pumps with one turbine so the pressure on the turbine is higher. And you can't just increase the size of the turbine without increasing the fuelflow because the turbine would loose efficiency and so the engine would loose efficiency. That's also the case if you throttle down an engine. So i still think FFSC is the way to go for methane.

The "bad" efficiency of LH2/LOX engines is mainly caused by the realy low density of H2. It's hard to run a turbine with H2 (e.g. on the expander cycle), so they can't get high pressure in the burning chamber. Methane has about four times the density of H2 and combined with LOX it is absolutly not hard to get high pump power and high chamber pressure. That's also the reason why they also use the oxygen-rich preburner. Because oxygen is much more dense so it can generate much more pressure through the turbines.

Because they can run the turbines at lower temperatures and don't have to use exotic materials and get even higher isp from FFSC. And mixing both mixtures and light it causes the reactions to go faster, which might lead to higher thrust.

http://spaceflight101.com/spacex-launch-vehicle-concepts-designs/ "The advantage of the full-flow cycle is that the turbines operate at lower temperatures since more mass passes through them leading to increased reliability and a longer engine life which is particularly important to potential re-use of the engine. In addition, this engine design can deliver higher chamber pressures and improve the efficiency of the engine." "Compared to RP-1, methane does not lead to coking of the engines which is a common problem with RP-1 that requires oxygen-rich combustion to limit coking, but creates a more corrosive environment."

But the coking temperature of methane is twice as high as the temperatures of a rocket engine, so that is not a problem with methane, right?

@shynung As far as i know, they can run the turbopump at cooler temperatures due to the lower temperatures of methane or so. So that they don't have to use exotic materials. And the russians already did oxygen-riched staged combustion with RP-1 which has much more carbon parts than methane, so that shouldn't be a real problem.

@sgt_flyer Well i just said that it depends on how you define the maximum isp. I wouldn't make an engine powered with electric fuel pumps. And i calculated some maximum isps in the comment above: ~453s for CH4 + LOX and ~575s for LH2 + LOX. And as far as i heard, FFSC saves some weight because it doesn't put so much stress on the turbines...

@shynung As i said: If you add energy by powering the fuel pumps with electric energy, you should get a higher isp. So it depends on how you define the maximum isp... But i think you should be able to get an isp of ~400 out of CH4/LNG + LOX... Update1: So i did the calculations: CH4 + 2 O2 => 2 H20 + CO2 + ~790 kJ/Mol 1000g*790kJ/Mol/(12g/Mol+4g/Mol+64g/Mol) => 9856 kJ/kg - Energy released by 1kg CH4 + LOX mixture => 9856000 J/kg (Standard unit) E=(m*v^2)/2 => v = sqrt(2*E/m) v = sqrt(2*9856000J/kg) = 4440 m/s 4440/9.81 = 453s So yes, it is possible to reach 400s with CH4. Update2: For LH2/LOX it is ~575s.

Well, that's true but that doesn't limit the isp. The isp is just limited by the exhaust velocity. But you can always increase the exhaust velocity by decreasing the diameter of your nozzle/pumping more fuel into the burning chamber. The fuel flow must be the same for the burning chamber and the nozzle, so the speed of the exhaust will increase if you decrease the diameter of the nozzle or pump more fuel into your burning chamber. So the only real limits are the material limits of the engine. You can't increase the pressure through the nozzle to thousends of bars. The nozzle wouldn't be able to handle that. But in theory, there is no limit for the isp. But that's also dependet on how you define the maximum isp. Because the fuel pumps can't produce a unlimited fuel flow. At least if you power them with the fuel it's pumping. If you power them with an electric engine, you should be able to get a realy high isp, but the battery you would have to use would be to heavy to use in a rocket. And then you would use an additional energy source which maybe conflicts with the definition of the maximum isp. So there is a theoretical isp maximum for every type of engine with it's fuel, but there isn't a general isp maximum for a fuel because it depends on the type of engine cycle you use.

@Elthy Why not? Chamber pressure increases the isp of every propellant. There is not a real isp maximum for fuels. Maybe a limit for the engineers because they can't increase the chamber pressure anymore, but not a theoretical limit.

Hello! I have some questions about FFSC, Methane and their combination in the Raptor engine (and it's vacuum version) SpaceX develops right now. First some links of my sources: http://www.scienceforums.net/topic/81051-staged-combustion-rocket-engines/ http://space.stackexchange.com/questions/3161/why-is-spacex-considering-methane-as-fuel-for-their-next-engine-the-raptor https://en.wikipedia.org/wiki/Staged_combustion_cycle#Full-flow_staged_combustion_cycle https://en.wikipedia.org/wiki/Comparison_of_orbital_rocket_engines https://en.wikipedia.org/wiki/Liquid_rocket_propellant#Bipropellants So, methane gains about 10s of specific impuls over rp-1 and has just about 20% less bulk density. If you have a look at the comparison of orbital rocket engines and sort it by highest pressure and have a look on the RD-180 1st stage engine: It has a atm isp of ~310s and a vacuum isp of ~340s but "just" uses oxygen-riched staged combustion with RP-1/LOX. So the isp of the Raptor engine should gain 10s from the higher isp of the fuel and 10s for using FFSC compared to the RD-180. So, if SpaceX optimizes the 1st stage version of the Raptor engine, they should get an isp of ~330s atm and ~360s vac, maybe even 370s. So i think the official isp of 321s atm and 363s vac are estimations for the first version or maybe for their tests and will be increased in the later versions. But as far as i know there is no official isp value for the upper stage version of the Raptor engine. So, let's have a look at the RD-0124. It uses the same combustion cycle as the RD-180 but has nearly half the camber pressure, a vacuum nozzle and uses RP-1/LOX. It has a vac isp of ~360s. I don't know why they used such low chamber pressure, maybe because they wanted to reduce weight. So with the full chamber pressure of oxygen-riched staged combustion it should get an vac isp of ~380s (compare Merlin 1D (280s/310s) with RD180 (310s/340s) and Merlin 1D Vacuum (~350s) with RD-0124 (~360s) --> +20s with full pressure). So, if they do FFSC with full pressure they should get around 400s vac isp for the upper stage Raptor engine. If they could archieve that, this would be the first chemical non-LH2 engine that reaches the 400s isp mark and nearly getting the same isp of some early LH2 engines. So my question: Is that a realistic calculation i did there? Or won't they use the full pressure of an FFSC (~31MPa)? And could you please list all advantages/disadvantages of Methane and FFSC compared to other propellants/engine cycles?

Changing the sampling works now. Thanks for your help!

@Noah_Blade I know but i would like my text to look normal because there are some texts that are barely readable.

@Speadge No. Which options should i change?

@Speadge Okay. I made a mistake. I didn't add -force-d3d11 to the link... I tried to open the link with -force-d3d11 and it's still the same problem...

@Speadge Sorry XD I thought that would be a marker to mark my comments as new content from the thread creator or something like that XD Creating a shortcut and disable DPI scaling works. But i usually start ksp with steam and directly changing the settings of the KSP.exe doesn't work with steam. So is there a way to do the same thing with steam? For example add something to the start parameters? And sorry for my bad english XD Update: Directly starting ksp.exe with disabled DPI scaling works. So is it possible that steam starts its games over a link which doesn't have "Disable DPI scaling" activated?

@MathiLpHD

Like that.

Hello! I have a problem with my version of KSP on my Laptop. When i use -force-d3d11 - which i need because the game starts to crash without - the text e.g. in the mission control becomes weird and it's hard to read that text. It works absolutly fine on my Gaming-PC. My gaming PC has an AMD graphicscard and my Laptop a Nvidia graphicscard. So could there be an issue with the current Nvidia driver? It also happens when i remove all my mods...