Final answer:
In the context of stabilized ground operations, Np refers to the number of propellers or engines on the aircraft. To avoid such operations, there are specific ranges of Np to consider.
Step-by-step explanation:
In the context of stabilized ground operations, Np refers to the number of propellers or engines on the aircraft. To avoid such operations, there are specific ranges of Np to consider. For example, in helicopters, stability is best achieved with an odd number of rotor blades, typically three (Np = 3) or five (Np = 5). This odd number of blades helps minimize vibrations and maintain a balanced operation.