MAE 5495: Launch Vehicle Analysis
Homework #2
Due: 28 Feb 2008, 1630 MST
1. (15%) Use the following parameters for an IDEAL rocket nozzle expansion.
Po = 4 MPa
To = 2500 K
Pa = 0.1 MPa
Dt = 1.0 cm
Products: Molecular Hydrogen and Carbon Dioxide (in a 1:1 molar ratio)
Calculate the following parameters for the nozzle throat AND the nozzle exit:
pressure, temperature, density, velocity, Mach number.
2. (20%) For the ideal rocket in Problem #1, calculate the mass flow, thrust, specific
impulse, and nozzle expansion ratio.
3. (15%) For an IDEAL rocket nozzle with a characteristic exhaust velocity of 1220
m/sec, a mass flow rate of 73.0 kg/sec, a thrust coefficient of 1.50, and a nozzle throat
area of 0.0248 m2, calculate the effective exhaust velocity, the thrust, the combustion
chamber pressure, and the specific impulse.
4. (20%) You are going to test fire the Spectra Rocket which uses a hypergolic
combination of hydrogen peroxide and methanol as propellants. However, estimates
of the performance need to be determined for comparison of the results. The
following conditions are expected:
To = 2710 K
Po = 4.082 MPa
Pa = 0.0762 MPa
 = 1.184 (products)
Molecular mass = 21.012 kg/kmol (products)
Dt = 1.78 cm
De = 12.45 cm
Tburn = 20 sec
Minitial = 50 kg
Calculate the following parameters: effective exhaust velocity, mass flow rate,
nozzle exit pressure, nozzle exit temperature, effective exhaust velocity, thrust
and specific impulse. (NOTE: DO NOT ASSUME IDEAL EXPANSION.)
c cF
5. (5%) Show that, Isp 
.
go
6. (5%) For a nozzle expansion ratio of 5, calculate all possible values for the nozzle
exit Mach number.
7. (20%) The Air Force wants to purchase a missile system capable of quick response
missile intercept using existing propulsion technology. The mission requires a delta v
of 1.6 km/sec (total, which includes all loss estimates) and a payload mass of 5 kg.
There are two propulsion systems to choose from:
a. Nitrous Oxide Monopropellant
Thrust = 1100 N
Isp = 200 sec
Finert = 0.4
b. Potassium Chlorate Solid Propellant
Thrust = 3000 N
Isp = 250 sec
Finert = 0.5
Use all of the design criteria at your disposal to evaluate the two systems. Assess
which system the Air Force should purchase for this particular missile system.