# US 5,704,567 A · Blade de-icer for rotary wing aircraft

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- Number: US 5,704,567 A
- Document ID: US5704567A
- Status: Granted
- Kind: A
- Application number: 08/543,688
- Filed: 1995-10-16
- Granted: 1998-01-06
- Earliest claimed: 1995-10-16
- Assignees: The United States of America as represented by the Secretary of the Army
- Inventors: John Michael Maglieri
- Web page: https://patentgrep.com/patent/US5704567A

## CPC

- B64D 15/12: by electric heating (heating arrangements specially adapted for transparent or reflecting areas H05B3/84)
- B64D: EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT

## Abstract

A blade de-icer for rotary wing aircraft comprises magnets placed around rotor mast and coils with laminated plates installed at the blade cuff of each rotor blade, in sufficient proximity to produce a high voltage, high current pulse every time a magnet and a coil pass each other while the rotor is turning. Electrically conductive cable or wire carries the current down each rotor blade to heating elements which melt any accreted ice on the blade. In one embodiment, magnetic metals are used. In another embodiment, electromagnets are used. In each embodiment, difficult switches for turning the de-icer on and off are provided.

## Claims

### Claim 1

A rotary blade de-icer for aircraft having a rotor mast and hub, and a multiplicity of airfoil rotor blades, each rotor blade having a root end and an outboard end, with a blade cuff at the root end and a leading edge and a lagging edge, comprising:
a multiplicity of magnets placed on the rotor mast; a coil integrated with laminated metal plates mounted on each rotor blade cuff; the magnets and the coil with laminated plates being mounted in sufficient proximity to each other so that as the rotor turns through its cycle the magnets pass the laminated metal plates so as to induce a high voltage and high current; electrically conductive lead means for carrying current from the coil down the length of each rotor blade; electrical resistance heating means connected to said lead means for imparting heat to the blade surface to melt accreted ice.

### Claim 2 (depends on 1)

The rotary blade de-icer described in claim 1 in which the electrically conductive lead means comprises small diameter cable.

### Claim 3 (depends on 1)

The rotary blade de-icer described in claim 1 further comprising switch means for turning the de-icer on and off.

### Claim 4

A rotary blade de-icer for aircraft having electrical power generating means; a rotor mast and hub, and a multiplicity of airfoil rotor blades, each rotor blade having a root end and an outboard end, with a blade cuff at the root end and a leading edge and a lagging edge, comprising:
a multiplicity of electromagnets placed on the rotor mast and connected by electrically conductive wire means to the electrical power generating means; a coil integrated with laminated metal plates mounted on each rotor blade cuff; the magnets and the coil with laminated plates being mounted in sufficient proximity to each other so that as the rotor turns through its cycle the magnets pass the laminated metal plates so as to induce a high voltage and high current; electrically conductive lead means for carrying current from the coil down the length of each rotor blade; electrical resistance heating means connected to said lead means for imparting heat to the blade surface to melt accreted ice.

### Claim 5 (depends on 4)

The rotary blade de-icer described in claim 4 in which the electrically conductive lead means comprises small diameter cable.

### Claim 6 (depends on 4)

The rotary blade de-icer described in claim 4 further comprising switch means for turning the electrical power generating means on and off.

### Claim 7 (depends on 6)

The rotary blade de-icer described in claim 6 in which the switch means comprises means for grounding the coil on the blade so that no voltage or current would be produced.

### Claim 8 (depends on 6)

The rotary blade de-icer described in claim 6 in which the switch means comprises means for energizing and deenergizing the electromagnets.

### Claim 9 (depends on 6)

The rotary blade de-icer described in claim 6 in which the switch means comprises shield means slidably mounted over the rotor mast to cover the magnets in the off position and expose them in the on position.