What is the difference between vacuum engine and sea level engine?

Vacuum-optimized engines are more complex and different than sea-level engines; they’re specifically designed to have a higher performance in the vacuum of space. A visible difference between the two engines is that the bell nozzle is larger in the Raptor vacuum engine.

Why are rocket engines more efficient in a vacuum?

On Earth, air tends to inhibit the exhaust gases getting out of the engine. This reduces the thrust. However, in space since there is no atmosphere, the exhaust gases can exit much easier and faster, thus increasing the thrust. Therefore, the rocket engine actually works better in space than here on Earth.

How does a rocket produce thrust in a vacuum?

In space, rockets zoom around with no air to push against. Rockets and engines in space behave according to Isaac Newton’s third law of motion: Every action produces an equal and opposite reaction. When a rocket shoots fuel out one end, this propels the rocket forward — no air is required.

Does rocket thrust increase with altitude?

At full throttle, the net thrust of a rocket motor improves slightly with increasing altitude, because as atmospheric pressure decreases with altitude, the pressure thrust term increases. Since ambient pressure changes with altitude, most rocket engines spend very little time operating at peak efficiency.

What is a vacuum Raptor engine?

The Raptor vacuum (or “RVac”) engine is basically a “space” version of the Raptor engines that will lift off from Earth underneath the Super Heavy booster. The vacuum engines have a much larger nozzle and are designed to operate more efficiently in the vacuum of space than the “sea-level” version of Raptor.

Why do engines create vacuum?

Restricting the airflow and creating vacuum helps slow the engine down and limit rpm. The vacuum created by the piston pulls air from outside, through the intake, into the cylinder. The throttle blades create restriction. This reduces the amount of air/fuel that goes into the cylinder.

How much thrust does a Raptor engine produce?

The Raptor subscale development engine produced approximately 1,000 kN (220,000 lbf) thrust.