Helicopter blade crack detection system
AssigneeThe United States of America as represented by the Secretary of the Air Force
InventorsGeoffrey P. Engels, Mark C. Thomas
Life of this patent
Estimating the term…
Abstract
The invention is a helicopter blade crack detection system for blades that are hollow and pressurized or evacuated to a low pressure A rotating assembly having a rotating indicator assembly photo-optically communicates to an airframe detection assembly providing high reliability, ease of maintenance, and EMI secured.
Claims3
A crack detection system for a helicopter having hollow spars in blades that are either pressurized or evacuated to a low pressure, said crack detection system comprising:
- rotating assembly means mounted on a helicopter rotor shaft-blade apparatus for detecting and indicating a crack in each of the blades;
- means mounted on a helicopter airframe for warning a pilot of the crack;
- and
- said rotating assembly means for detecting and indicating and said means for warning being in periodic photo-optic communications, said communications being between a light emitter of said means for detecting and a photo-optic detector of said means for warning located within a few thousands of an inch of each other.
A crack detection system for a helicopter having hollow spars in blades that are either pressurized or evacuated to a low pressure, said crack detection system comprising:
- rotating assembly means mounted on a helicopter rotor shaft-blade apparatus for detecting and indicating a crack in each of the blades;
- means mounted on a helicopter airframe for warning a pilot of the crack;
- and
- said rotating assembly means for detecting and indicating and said means for warning being in periodic photo-optic communications;
- said means for warning comprising:
- a source of power;
- a resetable warning circuit, said resetable warning circuit including:
- a resetable switch;
- a silicon controlled rectifier, a trigger circuit being in parallel with said silicon controlled rectifier, and
- a warning lamp;
- and
- said trigger circuit for receiving light from a light emitter of said means for detecting, said trigger circuit including:
- a photo-optic detector;
- a capacitor to ground;
- and
- a resistor.
Dependencies are inferred from the claim text.