- #1
gary350
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Does anyone know any Forumulas or how to calculate the dimensions of a pulse jet engine?
I have already built several PULSE JET engines that run by scaling up an existing hobby engine to a larger size. Problem is the scaled up models run but maybe they could run better. I can not find any formulas to design and build a PULSE JET ENGINE. Another problem is pulse jet engines run on air as the oxizider not oxygen like most liquid fuel rocket engines. I can not find any information for using AIR as the oxidizer in a rocket engine. My plan here was to use the formulas to design a liquid fuel rocket engine and use that information to build a Pulse Jet Engine but the physical size of the 100 lb thrust liquid fuel engine is many times smaller than a pulse jet engine so this will not work. I am using Gasoline as the fuel only because it is cheap and easy to get, Alcohol works much better. I am using gaseous oxygen as the oxidizer.
Calculations for a 100 lb thrust liquid fuel rocket engine, gasoline + oxygen.
Isp = Specific Impulse
Wo = lb of oxygen / sec
Wf = Lb of fuel / sec
Wt = wo + wf
Wo = .293 lb / sec
Wf = .117 lb / sec
Wt = .41 lb / sec
Gamma = 1.2
Dc = combustion chamber diameter = .4555"
Lc = combustion chamber length = 2.15"
Dt = nozzle diameter = .238"
Dc = nozzle exit = 1.2"
nozzle angle 15 degrees.
Trial and Error from scaling up a hobby engine to 100 lb Thrust. This works but I think it could work better. I have no idea how efficient my engine is. I have no information on AIR as an oxidizer to determine if my air intake is correct and the combustion chamber is the correct size. Gasoline + Air
Cr = Combustion chamber compression ratio = 2 to 1
Dc = combustion chamber diameter = 5.000""
Lc = combustion chamber length = 6.000"
Ai = Air intake = Dt x .8 = 2.000"
Dt = nozzle diameter = 2.5"
Tl = Tail Pipe length = 27"
Dc = nozzle exit = 3.5"
nozzle angle 15 degrees.
http://www.youtube.com/watch?v=ffjdgVU_RMQ&feature=PlayList&p=4448D61756AB7633&index=5
I have already built several PULSE JET engines that run by scaling up an existing hobby engine to a larger size. Problem is the scaled up models run but maybe they could run better. I can not find any formulas to design and build a PULSE JET ENGINE. Another problem is pulse jet engines run on air as the oxizider not oxygen like most liquid fuel rocket engines. I can not find any information for using AIR as the oxidizer in a rocket engine. My plan here was to use the formulas to design a liquid fuel rocket engine and use that information to build a Pulse Jet Engine but the physical size of the 100 lb thrust liquid fuel engine is many times smaller than a pulse jet engine so this will not work. I am using Gasoline as the fuel only because it is cheap and easy to get, Alcohol works much better. I am using gaseous oxygen as the oxidizer.
Calculations for a 100 lb thrust liquid fuel rocket engine, gasoline + oxygen.
Isp = Specific Impulse
Wo = lb of oxygen / sec
Wf = Lb of fuel / sec
Wt = wo + wf
Wo = .293 lb / sec
Wf = .117 lb / sec
Wt = .41 lb / sec
Gamma = 1.2
Dc = combustion chamber diameter = .4555"
Lc = combustion chamber length = 2.15"
Dt = nozzle diameter = .238"
Dc = nozzle exit = 1.2"
nozzle angle 15 degrees.
Trial and Error from scaling up a hobby engine to 100 lb Thrust. This works but I think it could work better. I have no idea how efficient my engine is. I have no information on AIR as an oxidizer to determine if my air intake is correct and the combustion chamber is the correct size. Gasoline + Air
Cr = Combustion chamber compression ratio = 2 to 1
Dc = combustion chamber diameter = 5.000""
Lc = combustion chamber length = 6.000"
Ai = Air intake = Dt x .8 = 2.000"
Dt = nozzle diameter = 2.5"
Tl = Tail Pipe length = 27"
Dc = nozzle exit = 3.5"
nozzle angle 15 degrees.
http://www.youtube.com/watch?v=ffjdgVU_RMQ&feature=PlayList&p=4448D61756AB7633&index=5
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