Zenith-Add horsepower, NASA-add drag: to create lift. How is this possible? Available horsepower and adding drag to an airplane both create extra lift?  How is that possible?


Available Horsepower

According to the Zenith, available horsepower not used to overcome form drag and induced drag contributes to rate of climb.
Adding drag

NASA's report on the X57, states that drag might need to be added to get rid of excess thrust to create more lift.

From the conclusion of that NASA report on span-wise propellers generating lift:


  A potential constraint on the design of the high-lift propellers system is the total thrust. If large amounts of lift augmentation are required from the propellers, then high thrust values from the high-lift propellers are likely. If these propellers produce excess thrust, then the aircraft will be unable to sustain flight at the desired speed. This implies that drag producing devices may need to be added to the aircraft or the primary propellers operated as windmills to produce additional drag.


(High-Lift Propeller System Configuration Selection for NASA's SCEPTOR Distributed Electric Propulsion Flight Demonstrator, NASA)

This concept seems to be exactly opposite of the first concept!!
Rumours: Ultralights reach a max speed, any extra power is then converted to lift. Is this true?


How do these concepts work?
Equating rate of climb with more lift is wrong. In order to climb the aircraft needs more thrust but a bit less lift. Therefore, the first statement is wrong: Adding more power does not create more lift. The only case where this happens is at high speed and the maximum sustainable lift coefficient: More power allows to fly at a higher load factor, but depending on the flight envelope, might result in a crash. The explanation does not make that connection, so it is wrong.

The second explanation is special for the X-57 because the concept uses the propeller slipstream to create blown lift. At low speed, the thrust needed to maintain flight speed is low and might not be sufficient to create enough lift on the small wing. Adding some drag allows to fly at higher thrust without climbing away. But only in this special case when most of the wing is in the propeller slipstream. So the second statement is correct but only for a single case.



Artist concept of the NASA X-57 Maxwell (image source).