#!/usr/bin/env python
# coding: utf-8

# # Aerobee 150 Engine
# 
# The Aerobee 150 flew on an AJ11-26 IRFNA and ANFA hypergolic pressure fed liquid motor.
# 
# We have some information to start with.

# In[1]:


from math import pi, log

# Physics
g_0      =     9.80665   # kg.m/s^2 Standard gravity

# Chemistry
rho_rfna =   1500.0      # kg/m^3   Density of IRFNA
rho_fa   =   1130.0      # kg/m^3   Density of Furfuryl Alcohol
rho_an   =   1021.0      # kg/m^3   Density of Aniline

# Data
Isp       =   209.0      # s       Average Specific Impulse accounting for underexpantion[1]
r         =     0.190    # m       Radius of the tanks (OD of rocket)[2]
Burn_time =    52.0      # s       Duration of the burn[2]
Mass_Fuel =   134.4      # kg      Mass of the fuel burnt[1]
Mass_Ox   =   343.9      # kg      Mass of the oxidizer burnt[1]


# First lets compute the fuel density, O/F ratio, mass flow rate, and Thrust

# In[2]:


rho_fuel = rho_an*0.65 + rho_fa*0.35
OF = Mass_Ox / Mass_Fuel
mdot = (Mass_Fuel+Mass_Ox) / Burn_time
Thrust = mdot*g_0*Isp

print "O/F ratio: %6.1f" % OF
print "mdot:      %7.2f [kg/s]" % mdot
print "Thrust:    %6.1f [kN]" % (Thrust/1000.0)


# In[3]:


# Mass flow for each propllent
mdot_o = mdot / (1 + (1/OF))
mdot_f = mdot / (1 + OF)
print "Ox flow:   %7.2f kg/s" % mdot_o
print "Fuel flow: %7.2f kg/s" % mdot_f

def tank_length(m, rho):
    l = m / (rho*pi*r*r)
    return l

l_o = tank_length(Mass_Ox, rho_rfna)
l_o += l_o*0.1 # add 10% for ullage
l_f = tank_length(Mass_Fuel, rho_fuel)
l_f += l_f*0.1 # add 10% for ullage

print "Ox tank length: . . . .%7.3f m" % l_o
print "Fuel tank length:      %7.3f m" % l_f


# ## References
# 
#  1. Vought Astronautics, PERFORMANCE SUMMARY FOR THE AEROBEE 150A SOUNDING ROCKET VEHICLE REPORT NO. AST/E1R-13319, April 18, 1961
#  1. NASA Technical Note D-3912: A Compendium Of NASA Aerobee Sounding Rocket Launchings For 1964