For light craft, full power is normally used during take off. Large transport category (airliner) aircraft will usually use a derated power takeoff, where less than full power is used. The aircraft is permitted to accelerate to rotation speed (often referred to as Vr) and then rotated off the ground gently. The term rotation is used, because the aircraft pivots or rotates about its centre of gravity (c.g.) when the flight controls are used to change the aircraft attitude. Usually the rotation is approximately 10 to 15 degrees nose up compared to the postion of the nose while on the ground. Autorotation is where an aircraft will do precisely this by itself when it reaches some speed.
If an obstacle needs to be cleared, the pilot lowers the nose just until the speed for maximum climb angle is achieved, Vx. If no obstacle needs to be cleared, or once an obstacle is cleared, the pilot further lowers the nose to accelerate to Vy, the speed at which climb is the most rapid. At this point the climb phase of flight begins.
See aircraft for more information.