So I know the simplified theory and basic principles here, Newton’s 3rd law, air compression and sudden exhaust and all, but it boggles me how this principle can lift, even move, 350 tons flying objects.
I get how it works but I need some kind of metaphor to understand and wrap my mind around the forces and amount of thrust at play here
In: Engineering
The engines are not doing much to lift the plane. They just need enough power to overcome the drag forces not the entire weight of the plane.
If you look at a typical passenger plane during take off they have a thrust to weight ratio of 0.2 to 0.3 typically. So the engines are only provided enough thrust to lift 1 third of the planes weight. And most modern jetliners have 2 engines so each could only lift 1/6 of the aircraft weight.
Also the type of engine effects how much trust it can typically produce. You original questions asks about turbojets but those are a specific type of engine that isn’t commonly used anymore. Modern passanger planes use high-bypass turbofan engines, which are more effecient at sub sonic speeds. They make most of their trust just by moving lots of air through the fan. Less than 10% of the air going in goes through the turbo core to power the engine. The rest just gets blown out the back.
Latest Answers