CONTROLLING PROPELLER ROTOR OVERSPEED

• US 20100066098A1
• Filed: 09/08/2009
• Published: 03/18/2010
• Est. Priority Date: 09/12/2008
• Status: Active Grant

• Current Assignee: Rolls-Royce PLC (Rolls-Royce Holdings Plc)
• Original Assignee: Rolls-Royce PLC (Rolls-Royce Holdings Plc)
• Inventors: GAINFORD, DAVID MICHAEL, HOLT, JONATHAN EDMUND
• Granted Patent: US 8,159,081 B2
• Time in Patent Office: Days
• US Class Current: 290/40.A
• CPC Class Codes: B64C 11/306 specially adapted for contrarotating propellers
• CPC Class Codes: B64C 11/48 Units of two or more coaxial propellers
• CPC Class Codes: B64D 2027/005 Aircraft with an unducted turbofan comprising contra-rotating rotors, e.g. contra-rotating open rotors [CROR]
• CPC Class Codes: B64D 2027/026 comprising different types of power plants, e.g. combination of an electric motor and a gas-turbines
• CPC Class Codes: B64D 27/00 Arrangement or mounting of power plants in aircraft; Aircraft characterised by the type or position of power plants
• CPC Class Codes: B64D 27/026 comprising different types of power plants, e.g. combination of a piston engine and a gas-turbine Hybrid electric aircraft B64D27/33
• CPC Class Codes: B64D 35/06 the propellers or rotors being counter-rotating
• CPC Class Codes: F01D 21/02 Shutting-down responsive to overspeed
• CPC Class Codes: F02C 9/00 Controlling gas-turbine plants; Controlling fuel supply in air- breathing jet-propulsion plants controlling air intakes F02C7/057; controlling turbines F01D; controlling compressors F04D27/00; controlling in general G05
• CPC Class Codes: F05D 2270/021 to prevent overspeed
• CPC Class Codes: Y02T 50/40 Weight reduction
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft

Abstract

An engine having at least one stage of propeller rotor blades, and a load, the at least one stage being associated with electrical generation means to generate electricity for the load. The load is switchable into a high load state in the event of an overspeed signal from the rotor blades. Also a method of controlling rotor overspeed of an engine, characterised by the steps of:

• • i. detecting an overspeed signal from the at least one stage, and
  • ii. switching the load into a high load state to apply torque to the at least one stage to counteract the overspeed.

Claims

1. An engine having at least one stage of propeller rotor blades, and an electrical load, the at least one rotor blade stage being coupled to electrical generation means to generate electricity for the load, wherein the electrical load is switchable into a high load state in response to an overspeed signal relating to the at least one rotor blade stage.

2. An engine as claimed in claim 1 wherein there is more than one electrical load, each load being switchable into a high load state in response to an overspeed signal.

3. An engine as claimed in claim 1 wherein the electrical generation means is positioned between the at least one stage of propeller rotor blades and a fixed structure of the engine.

4. An engine as claimed in claim 1 wherein there are two stages of propeller rotor blades and the electrical generation means is positioned between the two stages.

5. An engine as claimed in claim 1 wherein the electrical generation means is positioned between the at least one stage and another rotating component in the engine.

6. An engine as claimed in claim 1 wherein the engine further comprises detector means to detect a rotor overspeed condition and produce the overspeed signal.

7. An engine as claimed in claim 1 wherein the engine further comprises detector means to detect an impending rotor overspeed condition and produce the overspeed signal.

8. An engine as claimed in claim 1 wherein the engine further comprises control means to switch the electrical load into a high load state in the event of an overspeed signal.

9. An aircraft comprising

a fuselage

an engine affixed to said fuselage and having an output shaft;

at least one stage of propeller rotor blades attached to said output shaft,

an electrical load,

the rotor blades stage being coupled to electrical generation means to generate electricity for the load, wherein the electrical load is switchable into a high load state in response to an overspeed signal relating to the at least one rotor blade stage.

10. A method of controlling rotor overspeed of an engine, the engine having at least one stage of propeller rotor blades, an electrical load and means to generate electricity for the load, the method characterised by the steps of:

i. detecting an overspeed signal relating to the at least one stage, and

ii. switching the load into a high load state to apply torque to the at least one stage to counteract the overspeed.

11. A method as claimed in claim 10 wherein step 10i further comprises the step of detecting when the at least one stage is within a predetermined overspeed range.

12. A method as claimed in claim 10 wherein the engine has more than one load and step 10ii further comprises the step of switching at least one load into a high load state.

13. A method as claimed in claim 10 wherein the engine has more than one load and step 10ii further comprises the step of switching at least one load into a high load state and at least one other load into a normal load state.

14. A method as claimed in claim 11 wherein the overspeed range is set to be greater than or equal to zero rpm to provide rotor braking.