How do RC Jet Engines actually work?

You may think of flying RC jets as just a fun, relatively inexpensive hobby. But it might surprise you to know that there’s some real, serious science behind the engines that power many of these RC jets. Here’s a brief lesson on how RC jet engines work.

Let’s look at turbojet engines first. The best way to understand how these work in RC jets is to first look at how real jet engines work.

The most sophisticated of jets use turbines that compress an air-fuel mixture before igniting it. Because a turbine consists of sets of moving blades attached to an axle, when the turbine blades are spinning, they move air through themselves and toward the back of the aircraft.

Basically, the turbojet engine works like this: Air enters the turbine and is compressed. This compressed air is then sent to the combustion chamber, where it is mixed with fuel. After this, ignition takes place. The hot air that results from this exits the jet’s engine. Before it does this, though, the hot air moves through a gas turbine that powers the compressor.

Turbojet engines are efficient, but they are not used in planes such as subsonic aircraft because they are too noisy. Turbojet engines are more appropriate for high-speed flying that exceeds the speed of sound. Commercial jet aircraft, of course, don’t operate at supersonic speeds.

For commercial aircraft, then, the choice is the turbofan design. This engine operates on the same principle as does the turbojet engine. Instead of routing its intake air through a combustion chamber, though, it allows a small amount of fuel to exit the engine unburned.

Cool air is then mixed with the exhaust. This reduces the exhaust speed and increases fuel efficiency.

RC jet engines work in mostly the same way as do those in real jets. However, instead of using an axial turbine compressor, like real jets do, RC jet engines rely on a centrifugal compressor. This type of compressor forces air outwards after it enters the engine. This causes it to hit the engine case and then get compressed.

Centrifugal compressors rely on fewer moving parts than do axial turbine compressors. Because of this, they are more efficient for smaller applications.

Learning how RC jet engines work won’t help you become a better flyer.

But the science behind RC flying will help you better understand the hobby. And anything that does that is worth knowing, right?