For takeoff and maximum Np, what is the upper limit?

The upper limit for takeoff and maximum NP (propeller speed) being set at 100% is consistent with many aircraft operating procedures. When it comes to the performance of an aircraft during takeoff, it is crucial that the propeller operates within its prescribed limits to ensure safety and efficiency. Operating at 100% NP corresponds to the maximum rated speed for the propeller, as specified in the aircraft's flight manual.

Exceeding this limit can lead to increased stress on the propeller and associated systems, which could potentially result in mechanical failure or reduced lifespan of the components. Each aircraft will have specific limitations based on design and engineering parameters, and typically, 100% NP aligns with the optimal performance needed for safe operation during critical phases like takeoff.

It's important to adhere to these operational limits to maintain safety standards and avoid scenarios that could jeopardize the flight. The other percentages listed would indicate levels that either fall short of maximum permitted values or exceed the safe operational limits outlined for takeoff conditions.