What is the Air/Propane mixture Ratio? The Fuel Air Ratio of a Jet Engine is 15 to 1. This is for JP4. What is the Fuel Air Ratio for Propane Gas? I have learned the only difference between a rocket engine and pulse jet engine is the pulse jet runs on the oxygen that is in the air (30% oxygen + 70% nitrogen) while the rocket engine runs on pure oxygen. Many of the formulas for calculating the nozzle diameter etc. are the same for both types of engines. In order to do the calculation for a pulse jet engine running on propane I need to know the Air Fuel Mixture Ratio for and Air/Propane mixture. Confliction information here. Book #1. Propulsion Systems for Guided Missiles. Mixture ratio for Oxygen/Hydrogen is 5.33 to 1. Mixture ratio for Oxygen/Ethyl Alcohol is 1.5 to 1. Mixture ratio for Oxygen/gasoline is 3.0 to 1. Mixture ratio for Oxygen/Propane is 4.5 to 1. Book #2. Liquid Fuel Rocket Engines. Mixture ratio for Oxygen/Hydrogen is 3.5 to 1. Mixture ratio for Oxygen/Methyl Alcohol is 2.2 to 1. Mixture ratio for Oxygen/gasoline is 2.5 to 1. Mixture ratio for Oxygen/Propane is Not Available. I assume if for example since air is 30% oxygen I should be able to divide the Oxygen mixture ratio for a Rocket Engine by .3 to get the Air/Fuel Mixture Ratio for a Pulse Jet Engine. Is it correct to assume this??? The mixture ratio of Oxygen/Propane is 4.5/1 then the mixture ratio for Air/Propane should be 4.5/.3=15 or 15/1. Is this correct??? The Fuel Air Ratio of a Jet Engine is 15 to 1. The future belongs to those who take risks! If you don't risk anything, you risk even more!