An example of the second situation is a rigid rotor moving in field-free space.

In first approximation a molecule may be seen as a rigid rotor.

The rigid rotor is a good starting point from which to construct a model of a rotating molecule.

The rigid rotor is a mechanical model that is used to explain rotating systems.

An arbitrary rigid rotor is a 3-dimensional rigid object, such as a top.

This constraint results in the observed selection rules for the rigid rotor:

Lockheed began developing its rigid rotor concept with the CL-475 helicopter design in 1959.

Even in such a case the rigid rotor model is a useful point of departure (zeroth-order model).

The classical kinetic energy T of the rigid rotor can be expressed in different ways:

In a rigid rotor system, each blade flaps and drags about flexible sections of the root.

Often the kinetic energy is written as a function of the angular momentum of the rigid rotor.

A rigid rotor has a well-defined, time-independent, angular momentum.

The second term is the rotational term akin to the kinetic energy of the rigid rotor.

A special rigid rotor is the linear rotor which requires only two angles to describe its orientation.

The linear rigid rotor model consists of two point masses located at fixed distances from their center of mass.

The explicit form of the rigid rotor angular momentum operators is given here (but beware, they must be multiplied with ).

Lockheed had counted on the Cheyenne to establish itself in the helicopter market with its rigid rotor technology, but the ambitious project was unsuccessful.

As flight testing progressed, the original three-bladed, rigid rotor system demonstrated instability at higher speed ranges.

Similarly, it became apparent that the rigid rotor system was going to require extensive redesign of the aircraft, and this effort was dropped as well.

A rigid rotor system is mechanically simpler than a fully articulated rotor system.

The angular velocity vector of the rigid rotor is not constant, but satisfies Euler's equations.

The linear rigid rotor model can be used in quantum mechanics to predict the rotational energy of a diatomic molecule.

The choice of a rigid rotor meant that the helicopter was more agile than it would have been with a flapping rotor.

The Air Force therefore ordered Kellett to design a new, rigid rotor system for the XR-8.

The rigid rotor system also negates the danger of mast bumping inherent in teetering rotors.