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Post by nivik on Mar 22, 2017 15:34:36 GMT
Interesting. I'm not in a position to take a stab at it quite yet (at work), but I've been getting back into the game recently and I like the idea of designing missiles to others' requirements.
50kg is a lot more payload than I usually design around, and 10.0g initial acceleration is a lot more TWR.
I might see what I can do with an NTR-based KKV. My decane NTRs top out at around 5.35 km/s, so dropping 350 m/s of efficiency probably would give me some wiggle room for increased thrust. That'd allow a relatively low mass ratio of 2.72-ish. I'll try to remember to play with that when I get home.
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Post by Enderminion on Mar 22, 2017 15:44:25 GMT
Interesting. I'm not in a position to take a stab at it quite yet (at work), but I've been getting back into the game recently and I like the idea of designing missiles to others' requirements. 50kg is a lot more payload than I usually design around, and 10.0g initial acceleration is a lot more TWR. I might see what I can do with an NTR-based KKV. My decane NTRs top out at around 5.35 km/s, so dropping 350 m/s of efficiency probably would give me some wiggle room for increased thrust. That'd allow a relatively low mass ratio of 2.72-ish. I'll try to remember to play with that when I get home. RP-1 acts like dodecane if you are into that kind of stuff.
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Post by nivik on Mar 22, 2017 16:12:26 GMT
Interesting. I'm not in a position to take a stab at it quite yet (at work), but I've been getting back into the game recently and I like the idea of designing missiles to others' requirements. 50kg is a lot more payload than I usually design around, and 10.0g initial acceleration is a lot more TWR. I might see what I can do with an NTR-based KKV. My decane NTRs top out at around 5.35 km/s, so dropping 350 m/s of efficiency probably would give me some wiggle room for increased thrust. That'd allow a relatively low mass ratio of 2.72-ish. I'll try to remember to play with that when I get home. RP-1 acts like dodecane if you are into that kind of stuff. Yeah, I need to do a quick refresher on the various NPR propellants. I settled on decane as my main choice for capital ships early on, but I haven't really dug into them much for missile propellant. For missiles, I really value propellant density; more dense fuel means a smaller missile, which means the missile's a smaller target, it uses less armor mass for the same armor thickness, and the ammunition takes less space per missile, which means smaller, lighter launchers and magazines. I'll need to do some research. :3
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Post by someusername6 on Mar 22, 2017 23:53:24 GMT
KKV is the cheapest payload by far. So if we are optimizing for cost, an inert payload is definitely the way to go. Otherwise, I'd just go with flak or explosive payloads with the lowest amount of explosive allowed with a cheap and dense material for the fragments. But I do like my idea of a futuristic marketplace corporation delivering goods via missiles, 50 kg at a time. UPS Next Synod Missile. You *could* build a missile for this thread where the payload is a 50kg cargo module. Then bill yourself as a high speed delivery service -- at least 5 km/s, or your money back. Edit: Example submission with 50 kg cargo bay CargoModule 50.0 kg Cargo Bay Mass_kg 50 AspectRatio 3
CombustionRocketModule Micro HF Ungimballed UsesCustomName true Reaction Fluorine Hydrogen StoichiometricMixtureRatio 1 ThermalRocket ChamberComposition Vanadium Chromium Steel ThroatRadius_m 0.001 ChamberWallThickness_m 0.0002 ChamberContractionRatio 100 NozzleExpansionRatio 85 NozzleExpansionAngle_degrees 12 RegenerativeCooling_Percent 1 Injector Composition Lithium PumpRadius_m 0.027 RotationalSpeed_RPM 49 GimbalAngle_degrees 0
PropellantTankModule 19.0 kg Fluorine Tank Detachable UsesCustomName true Propellant Fluorine StructureComposition Boron ReactionMass_kg 19 HeightToRadiusRatio 20 AdditionalArmorThickness_m 0 External ExplosiveBoltMass_kg 0.001 ExplosiveBoltComposition Nitrocellulose
PropellantTankModule 1.00 kg Hydrogen Tank Tall Detachable UsesCustomName true Propellant Hydrogen StructureComposition Boron ReactionMass_kg 1 HeightToRadiusRatio 20 AdditionalArmorThickness_m 0 External ExplosiveBoltMass_kg 0.001 ExplosiveBoltComposition Nitrocellulose
PropellantTankModule 19.0 kg Fluorine Tank UsesCustomName false Propellant Fluorine StructureComposition UHMWPE ReactionMass_kg 19 HeightToRadiusRatio 10 AdditionalArmorThickness_m 0
PropellantTankModule 1.000 kg Hydrogen Tank UsesCustomName false Propellant Hydrogen StructureComposition UHMWPE ReactionMass_kg 1 HeightToRadiusRatio 10 AdditionalArmorThickness_m 0
CraftBlueprint Torpedo Delivery Modules 50.0 kg Cargo Bay 1 0 null 0 Aggressive Remote Control 1 0.55846 null 0 Micro HF Ungimballed 16 0 null 0 19.0 kg Fluorine Tank Detachable 4 0.72423 null 0 1.00 kg Hydrogen Tank Tall Detachable 4 0.71371 null 0.79 19.0 kg Fluorine Tank 1 0 null 0 1.000 kg Hydrogen Tank 1 0 null 0 19.0 kg Fluorine Tank Detachable 2 2.0085 null 0 1.00 kg Hydrogen Tank Tall Detachable 2 2.03 null 1.57 Armor ArmorLayers Nitrile Rubber 0.005 0 0 1 1
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Post by Durandal on Mar 23, 2017 1:00:18 GMT
You *could* build a missile for this thread where the payload is a 50kg cargo module. Then bill yourself as a high speed delivery service -- at least 5 km/s, or your money back. Edit: Example submission with 50 kg cargo bay CargoModule 50.0 kg Cargo Bay Mass_kg 50 AspectRatio 3
CombustionRocketModule Micro HF Ungimballed UsesCustomName true Reaction Fluorine Hydrogen StoichiometricMixtureRatio 1 ThermalRocket ChamberComposition Vanadium Chromium Steel ThroatRadius_m 0.001 ChamberWallThickness_m 0.0002 ChamberContractionRatio 100 NozzleExpansionRatio 85 NozzleExpansionAngle_degrees 12 RegenerativeCooling_Percent 1 Injector Composition Lithium PumpRadius_m 0.027 RotationalSpeed_RPM 49 GimbalAngle_degrees 0
PropellantTankModule 19.0 kg Fluorine Tank Detachable UsesCustomName true Propellant Fluorine StructureComposition Boron ReactionMass_kg 19 HeightToRadiusRatio 20 AdditionalArmorThickness_m 0 External ExplosiveBoltMass_kg 0.001 ExplosiveBoltComposition Nitrocellulose
PropellantTankModule 1.00 kg Hydrogen Tank Tall Detachable UsesCustomName true Propellant Hydrogen StructureComposition Boron ReactionMass_kg 1 HeightToRadiusRatio 20 AdditionalArmorThickness_m 0 External ExplosiveBoltMass_kg 0.001 ExplosiveBoltComposition Nitrocellulose
PropellantTankModule 19.0 kg Fluorine Tank UsesCustomName false Propellant Fluorine StructureComposition UHMWPE ReactionMass_kg 19 HeightToRadiusRatio 10 AdditionalArmorThickness_m 0
PropellantTankModule 1.000 kg Hydrogen Tank UsesCustomName false Propellant Hydrogen StructureComposition UHMWPE ReactionMass_kg 1 HeightToRadiusRatio 10 AdditionalArmorThickness_m 0
CraftBlueprint Torpedo Delivery Modules 50.0 kg Cargo Bay 1 0 null 0 Aggressive Remote Control 1 0.55846 null 0 Micro HF Ungimballed 16 0 null 0 19.0 kg Fluorine Tank Detachable 4 0.72423 null 0 1.00 kg Hydrogen Tank Tall Detachable 4 0.71371 null 0.79 19.0 kg Fluorine Tank 1 0 null 0 1.000 kg Hydrogen Tank 1 0 null 0 19.0 kg Fluorine Tank Detachable 2 2.0085 null 0 1.00 kg Hydrogen Tank Tall Detachable 2 2.03 null 1.57 Armor ArmorLayers Nitrile Rubber 0.005 0 0 1 1
Someone should make a cargo pod with the same mass as a 1-man crew module and make a drop pod.
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Post by nivik on Mar 23, 2017 23:50:04 GMT
Edit: I missed the "not NTR" requirement. Oh well. Leaving it up!Here's my stab at it. Main stats are that it's 31.5x455cm, 5.01km/s dV, 10.8g initial acceleration with an RP-1 NTR. Mass is 252kg, cost is 1.60kc. The reason for the mass (and consequentially, the price) is the armor. I'm using 5mm of amorphous carbon, with 0.5mm graphite aerogel underneath, with 0.5mm spacing between the aerogel layer and internal components. The amorphous carbon gives the missile's body a large heat capacity and the gel spreads the heat around. I'm a bit out of the loop when it comes to anti-laser armor on missiles, but this seems to work better than some of the alternatives I've tried. Warhead is 49.9 kg of Selenium around 100g of nitrocellulose, resulting in around 500x 100g pieces of shrapnel. Hard detonation is at 10 meters, which results in some very satisfyingly ragged, nasty-looking holes in things. I'm not 100% happy with it -- the 5mm of armor seems like a bit much -- but it's a decent salvoed artillery missile; the individual missiles can take enough punishment to allow 15-20 of them to kill the laser frigate or gunship pretty reliably, even fired at ranges that require a lengthy coast phase. The burn time is pretty solid and the turnabout time is under 700ms, which makes it pretty nimble in the terminal phase. Image: Export File:
ExplosiveModule Grey Chipmunk Warhead UsesCustomName true Length_m 0.33 ExplosiveMass_kg 0.1 ExplosiveComposition Nitrocellulose ShrapnelMass_kg 49.9 ShrapnelComposition Selenium Detonator HardRange_km 0.01 ActivationRange_km 0.03 MinimumRange_km 0 OverrideTimer_s 120 TargetsShips true TargetsShots false
NuclearThermalRocketModule Grey Chipmunk Engine UsesCustomName true ReactorCoreHeight_m 0.016 NuclearReactor Coolant RP-1 Moderator Titanium Nitride ModeratorMass_kg 0 Fuel U-233 Dioxide FuelMass_kg 0.1 FuelEnrichment_Percent 0.4 ControlRodComposition Boron Nitride ControlRodMass_kg 0.06 NeutronReflector Pyrolytic Carbon ReflectorThickness_m 0 AverageNeutronFlux__m2_s 2e+020 ThermalRocket ChamberComposition Boron ThroatRadius_m 0.0035 ChamberWallThickness_m 0.00085 ChamberContractionRatio 62 NozzleExpansionRatio 220 NozzleExpansionAngle_degrees 14 RegenerativeCooling_Percent 0.054 Injector Composition Lithium PumpRadius_m 0.063 RotationalSpeed_RPM 320 Gimbal InnerRadius_m 0.092 ArmorComposition Graphite Aerogel ArmorThickness_m 0.0001 MomentumWheels Composition Lithium RotationalSpeed_RPM 5800 GimbalAngle_degrees 15
PropellantTankModule Grey Chipmunk Fuel Tank UsesCustomName true Propellant RP-1 StructureComposition UHMWPE ReactionMass_kg 77 HeightToRadiusRatio 9.4 AdditionalArmorThickness_m 0
PropellantTankModule Grey Chipmunk Fuel Tank UsesCustomName true Propellant RP-1 StructureComposition UHMWPE ReactionMass_kg 77 HeightToRadiusRatio 9.4 AdditionalArmorThickness_m 0
CraftBlueprint Grey Chipmunk Missile Modules Grey Chipmunk Warhead 1 0 null 0 Default Remote Control 1 0.5 null 0 Grey Chipmunk Engine 1 0 null 0 Grey Chipmunk Fuel Tank 1 -0.5 null 0 Grey Chipmunk Fuel Tank 1 -0.25 null 0 50.0 cm x 0 m Spacer 1 5.7461 null 0 Armor ArmorLayers Graphite Aerogel 0.0005 0.0005 0 1 1 Amorphous Carbon 0.005 0 0 1 1
Certainly not an optimal entry, but I'm pleased with its performance, given the constraints.
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core2
New Member
Posts: 16
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Post by core2 on Mar 24, 2017 0:09:49 GMT
my try
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Post by Enderminion on Mar 24, 2017 0:28:26 GMT
I changed the areogel requirment, it is now 50cm
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Post by Dhan on Mar 24, 2017 2:10:02 GMT
That might mean that it's time for 5mm of microlatice for optimal mass cheesing. Farewell 200 credit shipping missile 7
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Post by nivik on Mar 24, 2017 5:35:50 GMT
That might mean that it's time for 5mm of microlatice for optimal mass cheesing. Farewell 200 credit shipping missile 7 If you wanna cheese mass and cost, lithium or potassium would be a good choice. I mean, if chemical reactivity were modeled, you could use lithium armor and a fluorine tank as the payload, and have KKVs with extra detonatey goodness.
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Post by goduranus on Mar 25, 2017 0:28:05 GMT
In my opinion the way to go is to use hydrogen deuteride fuel for mass efficiency, and use drop tanks so you don't have to put much armor around the bulky tanks. Drop tanks are vulnerable to lasers but you use them up before you get into range anyways. 123kg
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Post by thorneel on Mar 25, 2017 15:01:52 GMT
Here is my entry: a dual warhead (~400x37g and ~7050x4.8g) flack missile. It is using Hydrogen Peroxide / RP-1 propulsion as per concretedonkey restock missiles for better density. As Hydrogen Peroxide is explosive, it is recommended to eject external fuel tanks before engagement. Armour is a rather standard 4 mm amorphous carbon with 1 mm diamond finish. As there was a slight performance margin, 1.8 cm of boron has been added under that at the nose, bringing it to exactly 5 km/s dV and 10 g initial acceleration. It is mostly a placeholder, feel free to replace it with something more useful to your needs. Note that flak and remote control haven't been particularly tuned, and the engine has a very low gimbal angle and speed, to keep low profile and make it easier for the AI. 50 kg Missile MkII.txt (3.56 KB)
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Post by zorbeltuss on May 10, 2017 17:27:27 GMT
Not happy with my submission, it shouldn't have to use lithium as armor, but that's what I get for down-scaling engines. Edit: Below is the missile export
NuclearThermalRocketModule 5.26 km/s RP-1 Gimballed Nuclear Thermal Rocket UsesCustomName false ReactorCoreHeight_m 0.08 NuclearReactor Coolant RP-1 Moderator Boron Carbide ModeratorMass_kg 0 Fuel U-233 Dioxide FuelMass_kg 0.46 FuelEnrichment_Percent 0.97 ControlRodComposition Boron Nitride ControlRodMass_kg 0.5491 NeutronReflector Tantalum Hafnium Carbide ReflectorThickness_m 0 AverageNeutronFlux__m2_s 1.17e+019 ThermalRocket ChamberComposition Boron ThroatRadius_m 0.024 ChamberWallThickness_m 0.0001 ChamberContractionRatio 5.912 NozzleExpansionRatio 28 NozzleExpansionAngle_degrees 10 RegenerativeCooling_Percent 0.048 Injector Composition Boron PumpRadius_m 0.065 RotationalSpeed_RPM 190 Gimbal InnerRadius_m 0.094 ArmorComposition Graphite Aerogel ArmorThickness_m 0.0001 ElectricActuators PermanentMagnet Aluminum Nickel Cobalt PowerConsumption_W 12 GimbalAngle_degrees 0.9
NuclearPayloadModule 15.3 kt Boosted Fission Nuke UsesCustomName false CoreComposition U-233 ReflectorComposition Tungsten SlowExplosive CombustionReaction Silicon Nanothermite DelayComposition Potassium DelayCompositionMassFraction 0.114 FastExplosive Nitrocellulose CoreMass_kg 1.6 Enrichment_Percent 0.97 HollowCoreRadius_m 0.103 InnerExplosiveWidth_m 0.0166 FusionBoost Deuterium Tritium FusionFuelDensity_kg__m3 290 Detonator HardRange_km 0 ActivationRange_km 0.1 MinimumRange_km 0.05 OverrideTimer_s 0 DelayedTrigger false TargetsShips true TargetsShots true
RemoteControlModule Default Remote Control Copy UsesCustomName true AspectRatio 0.5 HomingBehavior PropellantForBoostPhase_Percent 0.65 BoostPhase GuidanceLaw Augmented Proportional Navigation Accelerate true DampingEngineMultiplier 0.5 MidcoursePhase GuidanceLaw Augmented Proportional Navigation Accelerate true DampingEngineMultiplier 0.25 TerminalPhase GuidanceLaw Augmented Proportional Navigation Accelerate true DampingEngineMultiplier 9.9
PropellantTankModule 104 kg RP-1 Tank UsesCustomName false Propellant RP-1 StructureComposition Boron ReactionMass_kg 104 HeightToRadiusRatio 20 AdditionalArmorThickness_m 0
CraftBlueprint Challenger Missile Modules 5.26 km/s RP-1 Gimballed Nuclear Thermal Rocket 1 0 null 0 15.3 kt Boosted Fission Nuke 1 1.5308 null 0 Default Remote Control Copy 1 3.584 null 0 104 kg RP-1 Tank 1 1 null 0 Armor ArmorLayers Lithium 0.005 0 0 1 1
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Post by dwwolf on May 11, 2017 8:53:29 GMT
If you are building a KKV i dont see a point in using a 50 kg inert rad shield pill as the payload.
Part of that weight would be better off as a carbon steel nose cone underneath the anti-thermal armor. It should help negating the whipple shield if the impact is nose on. And still Better yet would be to use most of the extra mass as fuel.
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Post by vegemeister on May 11, 2017 12:00:51 GMT
If you are building a KKV i dont see a point in using a 50 kg inert rad shield pill as the payload. Part of that weight would be better off as a carbon steel nose cone underneath the anti-thermal armor. It should help negating the whipple shield if the impact is nose on. And still Better yet would be to use most of the extra mass as fuel. Not necessarily. There's a proof floating around somewhere that the mass ratio that maximizes kinetic energy for a given wet mass is e^2. That's approximately 7.389, and it corresponds to Δv equal to twice your engine's exhaust velocity. Though starting from the specified 5 km/s Δv in this thread, more fuel is going to be the answer for most reasonable engines. KKVs kind of suck though, in my experience. The first one makes a small hole through the center of the radiators, and every subsequent missile goes through the same hole. They probably are a good answer to pointy ships that fight nose-on, though, since a KKV has a good chance of coring the ship if it hits from that aspect.
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