This post seems completely divorced from reality. There are many overlooked issues:
- To hover, you need a thrust/weight ratio >= 1. Taking off vertically requires an even higher thrust/weight ratio. A modern Boeing 737 has a thrust/weight ratio of 0.15. So a comparable VTOL aircraft is going to need engines ≈7x more powerful than current ones. But those don't exist. The most powerful jet engine in the world (the 777's GE90-115B) can't lift a 737 straight up. An electric version? Forget about it. The best production electric motors are almost two orders of magnitude less powerful than the GE90-115B.
- Hovering and vertical takeoff are fraught with safety issues. With multiple engines, any failure creates a deadly thrust imbalance. You also have to avoid vortex ring state. And while VTOL craft like helicopters can autorotate, it takes a skilled pilot along with the right combination of velocity and height.[1]
- Landing on skyscrapers means you'll have to deal with higher winds than near the ground. While you can orient the craft in any direction, wind is not constant. Gusts and swirls from the skyscraper will make landing difficult.
I could see VTOL electric craft replacing helicopters, but passenger jets are not going away any time soon. The physics just don't work out for larger VTOL aircraft.
- To hover, you need a thrust/weight ratio >= 1. Taking off vertically requires an even higher thrust/weight ratio. A modern Boeing 737 has a thrust/weight ratio of 0.15. So a comparable VTOL aircraft is going to need engines ≈7x more powerful than current ones. But those don't exist. The most powerful jet engine in the world (the 777's GE90-115B) can't lift a 737 straight up. An electric version? Forget about it. The best production electric motors are almost two orders of magnitude less powerful than the GE90-115B.
- Hovering and vertical takeoff are fraught with safety issues. With multiple engines, any failure creates a deadly thrust imbalance. You also have to avoid vortex ring state. And while VTOL craft like helicopters can autorotate, it takes a skilled pilot along with the right combination of velocity and height.[1]
- Landing on skyscrapers means you'll have to deal with higher winds than near the ground. While you can orient the craft in any direction, wind is not constant. Gusts and swirls from the skyscraper will make landing difficult.
I could see VTOL electric craft replacing helicopters, but passenger jets are not going away any time soon. The physics just don't work out for larger VTOL aircraft.
1. https://en.wikipedia.org/wiki/Helicopter_height%E2%80%93velo...