Dr. Courtney said:jets have much larger exhaust velocities
Specific impulse (Isp) is a measure of the efficiency of a rocket or jet engine. It is the ratio of thrust produced to the rate of propellant consumption, and is typically measured in seconds.
The main difference between rocket specific impulse and jet engine specific impulse is the type of propellant used. Rocket engines use a chemical reaction to produce thrust, while jet engines use the combustion of fuel and air. This leads to differences in the amount of thrust produced and the rate of propellant consumption.
Rockets typically have a higher specific impulse than jet engines. This is because rockets carry their own oxidizer, while jet engines rely on the oxygen in the air for combustion. This allows rockets to produce more thrust for the same amount of propellant.
A higher specific impulse means that the engine is more efficient, as it can produce more thrust with less propellant. This leads to a longer burn time and higher velocities for rockets, and longer flight times and increased fuel efficiency for jet engines.
No, there are other factors that can affect the performance of a rocket or jet engine, such as the design and construction of the engine, the type of propellant used, and external factors like air resistance. However, specific impulse is an important factor in determining the overall efficiency and performance of the engine.