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N2O4/N2H4 IspVac = 322.9 sec MRcore = 1.26 MRthruster = 0.882 Rt = 0.356678 in At = 0.39967 in**2 Pc = 137 psia Fvac = 100 lbf |
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100 lbf Aerojet HiPAT R-4D | |
| RocketIsp version 0.1.12 | Sunday, Jul 19, 2026 at 09:17AM |
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N2O4/N2H4 IspVac = 322.9 sec MRcore = 1.26 MRthruster = 0.882 Rt = 0.356678 in At = 0.39967 in**2 Pc = 137 psia Fvac = 100 lbf |
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| Geometry |
|---|
| Input | |||
|---|---|---|---|
| Parameter = | Value | Alt Value | Description |
| cham_conv_deg = | 30.00 deg | half angle of conical convergent section | |
| CR = | 2.5 | chamber contraction ratio (Ainj / Athroat) | |
| eps = | 375 | nozzle area ratio (Aexit / Athroat) | |
| LchamberInp = | None in | user input value of chamber length (will override all other entries) | |
| LchmMin = | 1.000 in |
2.540 cm 0.083 ft |
minimum chamber length (will override LchmOvrDt) |
| LchmOvrDt = | 3 | ratio of chamber length to throat diameter (Lcham / Dthrt) | |
| LnozInp = | None in | user input nozzle length (will override pcentBell) | |
| pcentBell = | 80 | nozzle percent bell (Lnoz / L_15deg_cone) | |
| RchmConv = | 1 | radius of curvature at start of convergent section (Rconv / Rthrt) | |
| RdwnThroat = | 1 | radius of curvature just downstream of throat (Rdownstream / Rthrt) | |
| Rthrt = | 0.357 in |
0.906 cm 0.030 ft |
throat radius |
| RupThroat = | 1.5 | radius of curvature just upstream of throat (Rupstream / Rthrt) | |
| Output | |||
|---|---|---|---|
| Parameter = | Value | Alt Value | Description |
| Ainj = | 0.999 in**2 | 6.446 cm**2 | area of injector |
| At = | 0.400 in**2 | 2.579 cm**2 | throat area |
| Dexit = | 13.814 in |
35.088 cm 1.151 ft |
nozzle exit diameter |
| Dinj = | 1.128 in |
2.865 cm 0.094 ft |
diameter of injector |
| Dthrt = | 0.713 in |
1.812 cm 0.059 ft |
throat diameter |
| entrance_angle = | 39.79 deg | nozzle initial expansion angle | |
| exit_angle = | 7.65 deg | nozzle exit angle | |
| Lcham_conv = | 0.598 in |
1.519 cm 0.050 ft |
length of convergent section of chamber |
| Lcham_cyl = | 1.542 in |
3.917 cm 0.129 ft |
length of cylindrical section of chamber |
| Lnoz = | 19.557 in |
49.675 cm 1.630 ft |
nozzle length |
| Ltotal = | 21.697 in |
55.111 cm 1.808 ft |
nozzle + chamber length |
| Rinj = | 0.564 in |
1.432 cm 0.047 ft |
radius of injector |
| Vcham = | 1.9 in**3 | 31.9 cm**3 | approximate chamber volume |
| N2O4/N2H4 Core Stream Tube |
|---|
| Input | |||
|---|---|---|---|
| Parameter = | Value | Alt Value | Description |
| adjCstarODE = | 1 | multiplier on NASA CEA code value of cstar ODE (default is 1.0) | |
| adjIspIdeal = | 1 | multiplier on NASA CEA code value of Isp ODE (default is 1.0) | |
| CdThroat = | 0.985274 |
Cd of throat (RocketThruster object may override) (MLP fit) |
|
| fuelName = | N2H4 | name of fuel (e.g. MMH, LH2) | |
| ignore_noz_sep = | 0 | flag to force nozzle flow separation to be ignored (USE WITH CAUTION) | |
| MRcore = | 1.26 | mixture ratio of core flow (ox flow rate / fuel flow rate) | |
| oxName = | N2O4 | name of oxidizer (e.g. N2O4, LOX) | |
| Pamb = | 0.00 psia |
0.00 MPa 0.00 atm 0.00 bar |
ambient pressure (for example sea level is 14.7 psia) |
| Pc = | 137.0 psia |
0.94 MPa 9.32 atm 9.45 bar |
chamber pressure |
| Output | |||
|---|---|---|---|
| Parameter = | Value | Alt Value | Description |
| CfAmbDel = | 1.82632 | delivered ambient thrust coefficient | |
| CfVacDel = | 1.82632 | delivered vacuum thrust coefficient | |
| CfVacIdeal = | 2.01252 | ideal vacuum thrust coefficient | |
| cstarERE = | 5729.7 ft/s | 1746.4 m/s | delivered core cstar |
| cstarODE = | 5787.6 ft/s | 1764.1 m/s | core ideal cstar |
| FvacBarrier = | 34.4 lbf | 152.9 N | vacuum thrust due to barrier stream tube |
| FvacCore = | 65.6 lbf | 291.9 N | vacuum thrust due to core stream tube |
| FvacTotal = | 100.0 lbf | 444.8 N | total vacuum thrust |
| gammaChm = | 1.13912 | core gas ratio of specific heats (Cp/Cv) | |
| IspDel = | 322.90 sec |
3166.57 N-sec/kg 3.17 km/sec |
<=== thruster delivered vacuum Isp ===> |
| IspDel_core = | 335.21 sec |
3287.30 N-sec/kg 3.29 km/sec |
delivered Isp of core stream tube |
| IspODE = | 362.02 sec |
3550.20 N-sec/kg 3.55 km/sec |
core one dimensional equilibrium Isp |
| IspODF = | 337.52 sec |
3309.90 N-sec/kg 3.31 km/sec |
core frozen Isp |
| IspODK = | 346.44 sec |
3397.42 N-sec/kg 3.40 km/sec |
core one dimensional kinetic Isp |
| MRthruster = | 0.882 | total thruster mixture ratio') | |
| MWchm = | 20.222 g/gmole | core gas molecular weight | |
| Pexit = | 0.0124 psia |
0.00 MPa 0.00 atm 0.00 bar |
nozzle exit pressure |
| TcODE = | 5521.3 degR |
3067.4 degK 2794.2 degC 5061.6 degF |
ideal core gas temperature |
| wdotFl = | 0.165 lbm/s | 0.075 kg/s | total fuel flow rate |
| wdotOx = | 0.145 lbm/s | 0.066 kg/s | total oxidizer flow rate |
| wdotTot = | 0.310 lbm/s | 0.140 kg/s | total propellant flow rate (ox+fuel) |
| At Injector Face | |||
| Parameter = | Value | Alt Value | Description |
| wdotFl_cInit = | 0.115 lbm/s | 0.052 kg/s | initial core fuel flow rate (before any entrainment) |
| wdotFlFFC = | 0.049 lbm/s | 0.022 kg/s | fuel film coolant flow rate injected at perimeter |
| wdotTot_cInit = | 0.260 lbm/s | 0.118 kg/s | initial core total flow rate (before any entrainment) |
| After Entrainment | |||
| Parameter = | Value | Alt Value | Description |
| wdotFl_b = | 0.078 lbm/s | 0.035 kg/s | barrier fuel flow rate (FFC + entrained) |
| wdotFl_c = | 0.087 lbm/s | 0.039 kg/s | final core fuel flow rate (injected - entrained) |
| wdotOx_b = | 0.036 lbm/s | 0.016 kg/s | barrier oxidizer flow rate (all entrained) |
| wdotOx_c = | 0.109 lbm/s | 0.050 kg/s | final core oxidizer flow rate (injected - entrained) |
| wdotTot_b = | 0.114 lbm/s | 0.052 kg/s | total barrier propellant flow rate (includes entrained) |
| wdotTot_c = | 0.196 lbm/s | 0.089 kg/s | total final core propellant flow rate (injected - entrained) |
| Efficiencies |
|---|
| Output | ||
|---|---|---|
| Parameter = | Value | Description |
| Isp = | 0.89194 | Overall Isp Efficiency |
| Noz = | 0.93530 | Nozzle Efficiency |
| ERE = | 0.99000 | (constant) Energy Release Efficiency of Chamber |
| FFC = | 0.96327 | (barrier calc) Fuel Film Cooling Efficiency of Chamber |
| Nozzle | ||
| Parameter = | Value | Description |
| Div = | 0.99403 | (simple fit eps=375, %bell=80) Divergence Efficiency of Nozzle |
| Kin = | 0.95696 | (MLP fit) Kinetic Efficiency of Nozzle |
| BL = | 0.98323 | (MLP fit) Boundary Layer Efficiency of Nozzle |
| Ignored Efficiencies |
|---|
| TP: Two Phase Efficiency of Nozzle |
| Barrier Stream Tube |
|---|
| Input | ||
|---|---|---|
| Parameter = | Value | Description |
| ko = | 0.035 | entrainment constant (typical value is 0.035, range from 0.03 to 0.06) |
| pcentFFC = | 30 | percent fuel film cooling ( FFC flowrate / total fuel flowrate) |
| Output | |||
|---|---|---|---|
| Parameter = | Value | Alt Value | Description |
| cstarERE_b = | 5389.9 ft/s | 1642.8 m/s | delivered cstar |
| cstarODE_b = | 5444.4 ft/s | 1659.4 m/s | ideal equilibrium cstar |
| fracEntr = | 0.247991 | fraction of core flow entrained into barrier | |
| fracKin_b = | 0 | fraction of kinetic completion in barrier | |
| IspDel_b = | 301.75 sec |
2959.11 N-sec/kg 2.96 km/sec |
delivered vacuum barrier Isp |
| IspODE_b = | 314.705 | sec. ideal equilibrium barrier Isp | |
| IspODF_b = | 311.85 sec |
3058.24 N-sec/kg 3.06 km/sec |
ideal frozen barrier Isp |
| IspODK_b = | 311.85 sec |
3058.24 N-sec/kg 3.06 km/sec |
vacuum kinetic Isp of barrier |
| MRbarrier = | 0.461848 | barrier mixture ratio at throat | |
| MRwall = | 0.158049 | mixture ratio at throat wall | |
| TcODE_b = | 3870.3 degR |
2150.1 degK 1877.0 degC 3410.6 degF |
average ideal ODE temperature of barrier gas |
| Twallgas = | 2476.6 degR |
1375.9 degK 1102.8 degC 2017.0 degF |
temperature of gas at throat wall (cooler upstream) |
| WentrOvWcool = | 1.30774 | ratio of entrained flow rate to FFC flow rate | |