Jet engines would be much more efficient if the exhaust were used to create lift instead of allowing the exhaust energy to be wasted. Lift could be created by allowing the exhaust to flow over a special protruding surface on top of the wing.

The engines would be on top of the wings instead of below; and the engine and wings would be moved forward to center the force.

This procedure would produce a lot of lift at zero velocity, which would allow very short runways for take-off. On aircraft carriers, catapults would not be needed. If the engine and its platform were tilted upward about 20 degrees, sharp-angle take-off would be possible. With normal flight, fuel efficiency should improve about 30%.

The jet engine exhaust would go over a protrusion, which would create a vacuum on the other side. Physicists have a slightly erroneous concept on how lift is created. The Bernoulli's principle tells physicists that the pressure of a fluid is inversely proportional to its velocity; so a fast-moving gas over an airplane wing causes lift. What they are missing is that the lift does not occur unless the moving gas passes over a protrusion (or wing curvature), which cause a vacuum pump to be generated on the other side.

It's easy to prove this effect by using a sheet of typing paper and blowing on one side. Nothing happens. Now create a crease down the center and blow across the crease. The paper moves toward the moving air. The air velocity is the same in both cases, but only if the air is moving over a crease is a vacuum force generated.

So a jet engine will produce a lifting force if the exhaust passes over a protrusion. A vacuum will be generated on the other side of the protrusion.

In the drawing, I show the protrusion approaching the exhaust stream. It does not need to touch the exhaust stream to create a vacuum on the other side of the protrusion. A small amount of air can be allowed to flow over the protrusion to cool the metal.

The shape of the protrusion and following plate would have a small amount of arc to increase the surface area of lift.

The engine height needs to be adjustable, so the engine lift can be reduced, as the plane velocity increases.

Simple minded persons would say it take so much energy to move a plane and lift it regardless of where the lifting is occurring. But there would be more efficiency if more force were created by the exhaust. And there is a lot of concern lately about shorter runways and vertical take-off. Using exhaust force for lift solves those problems.