When the F15 is using its thrust to suport itself (straight up) its behaving a lot more like a rocket than an airplane.
Airplanes do not need more thrust than lift to fly!
Thrust doesn't support an airplane, lift does. All the engines need to do is supply the speed to create the required dynamic pressure. In fact, with a Cl greater than 1 you can create more pressure differential over the wing than dynamic pressure.
How much dynamic pressure will be generated for an amount of thrust depends on the overall efficiency of the airplane.
Fakepilot
When you're looking at the thrust generated by piston engines, you have to look at the propulsive efficiency of the propeller/rotor blades. Engines produce power, propeller creates thrust. The propulsive efficiency of a helicopter main rotor is many times higher than most fixed wing engine propellers.
palgia