Why can commercial passenger (or cargo) jets have VTOL?
Another big issue for VTOL (vertical take off and landing) as opposed to STOVL (Short take off, vertical landing), is engine thrust v’s weight. In order to take off vertically you must have more combined engine thrust than weight. Harriers cannot take off vertically when fully loaded – their weight exceeds the thrust of their engine. Instead, they take a short run-up and then used vetical thrust to assist lift-off, or they use a short runway with a ramp at the end to launch into the air. With most commercial aircraft weighing in at over 100 tonnes fully laden, you would need very powerful engines to lift off vertically. As an example, the 747 weighs several hundred tonnes, but the engines they’ve had up until recently only put out about 25 tonnes of thrust each (about 54,000 pounds of thrust). It’s plenty for horizontal propulsion, but nowhere near enough for vertical. The most powerful jet engine I’m aware of at the moment are the Rolls Royce Trent turbofans. The Trent 900 series were
