What thrust [lbs] would this engine have to develop in order to reach 260kts in level flight at sea level standard conditions? Notice again that in equilibrium flight (i.e. straight and level, un-accelerated) thrust has to be equal to total drag, so look for the total drag at 260kts in your module 4 table. (In essence, this example is a reverse of the maximum speed question expressing it graphically within the diagram: We know the speed on the X-axis and have the thrust required curve; that gives us the intercept point on the curve through which the horizontal/constant thrust available line must go.)
Aircraft Mooney 20S Max gross weight 3368 lbs. wingspan 36.1 ft.
Total drag at 260 knots is 260.5683