The Osprey isn't a helicopter, instead it's a unique type of aircraft called a Tilt Rotor, because the rotors are mounted at the end of each wing, and can rotate, or tilt for horizontal flight, and be rotated back to the vertical, or upright position when hovering, or landing.

A military helicopter is a helicopter specially built or converted for use by military forces. The task of a military helicopter is a function of its design or conversion. The most common use of military helicopters is to transport troops, but transport helicopters can be modified or converted to perform other tasks.Beautiful helicopters, I want them to remain operational for many more decades, and should never be replaced unnecessarily.