Originally Posted by TangoKilo
Tell me what is pushing your plane along at "a speed" (against the resistance of aerodynamic drag) if there is no thrust.
Not only that, if your propulsor is not producing any thrust it is not doing any work so it won't need any power input. Why do you need "wide open throttle" to achieve maximum speed? Where is the power going?
A slight dive? If the efflux velocity is matching that of the free airstream the engine is just wasting energy as heat. A plane could never exceed the speed of the efflux from its propeller or jet engines in balanced level flight, which is one reason why hypersonic engines are exotic affairs or rockets. This does not mean that a plane can't go faster than the speed a prop can accelerate air on a stand. The prop adds speed to the airstream, so what you measure on a stand is not what you will have on the plane.