Method and apparatus for measuring deflection of rotating airfoils

An apparatus for measuring the deflection of a rotating member of finite radial length comprising:

• first illuminating means for illuminating the rotating member with a first high intensity light beam at one of a plurality of locations along its radial length spaced from the tip thereof at which deflection is to be determined;
• second illuminating means for illuminating a rotating reference location with a second high intensity light beam;
• means for reflecting and dispersing the first and second high intensity light beams from their respective locations as light impulses;
• means for sensing at least a portion of the reflected light impulses;
• means for converting the light impulses to electrical impulses;
• and
• means for measuring the time increment between the electrical impulse related to the deflection measurement location and the electrical impulse related to the rotating reference location.

A method of measuring deflection of a rotating member of finite radial length comprising the steps of:

• illuminating a portion of the radial length of the rotating member spaced from the tip thereof with a high intensity light beam projected from a location axially disposed from said member, the illuminated portion being that at which deflection is to be determined;
• illuminating a rotating reference location with the high intensity light beam;
• reflecting and disersing the high intensity light beam from both locations as light impulses;
• sensing at least a portion of the reflected light impulses with light sensitive means;
• converting the light beam impulses to electrical impulses;
• measuring the time increment between the electrical impulse related to the deflection measurement location and the electrical impulse related to the rotating reference location;
• and
• converting the time increment to a length dimension.

An apparatus for measuring the deflection of a rotating member of finite radial length comprising:

• illuminating means for illuminating the rotating member with a first high intensity light beam at a location along its radial length spaced from the tip thereof at which deflection is to be determined, and for illuminating a rotating reference location;
• means for reflecting and dispersing the high intensity light beam from both locations as light impulses;
• means for sensing at least a portion of each of the reflected light impulses;
• means for converting the light impulses to electrical impulses;
• and
• means for measuring the time increment between the electrical impulse related to the deflection measurement location and the electrical impulse related to the rotating reference location.

A method of measuring deflection of a rotating member of finite radial length comprising the steps of:

• illuminating a first photocell transducer affixed along the radial length of the rotating member spaced from the tip thereof with a first high intensity light beam projected from a location axially disposed from said member, the first photocell transducer being placed at the location at which deflection is to be determined, and converting the light beam into an electrical impulse;
• illuminating a second photocell transducer affixed to the rotating member as a rotating reference with a second high intensity light beam to generate a reference electrical impulse;
• measuring the time increment between the electrical impulses related to the first transducer and the second transducer;
• and
• converting the time increment to a length dimension.