TURBINE ENGINE HAVING TWO UNDUCTED PROPELLERS

• US 20130115083A1
• Filed: 07/13/2011
• Published: 05/09/2013
• Est. Priority Date: 07/23/2010
• Status: Abandoned Application

• Current Assignee: Snecma (Safran SA)
• Original Assignee: Snecma (Safran SA)
• Inventors: Vuillemin, Alexandre Alfred, Gaston
• Application Number:
  US13/810,833
• Publication Number:
  US 20130115083A1
• Time in Patent Office: Days
• US Class Current: 416/1
• CPC Class Codes: B64C 11/003 Variable-diameter propellers; Mechanisms therefor
• CPC Class Codes: B64C 11/06 for variable-pitch blades
• 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 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: F02K 3/072 with counter-rotating , e.g. fan rotors
• CPC Class Codes: F04D 19/024 with contrarotating parts
• CPC Class Codes: F04D 29/324 Blades
• CPC Class Codes: F04D 29/362 during rotation
• CPC Class Codes: F04D 29/666 by means of rotor construction or layout, e.g. unequal distribution of blades or vanes
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft

Abstract

A turbine engine including two outer coaxial counter-rotating unducted propellers, of an upstream propeller and a downstream propeller, respectively. The blades of the downstream propeller are retractable in the lengthwise direction thereof so as to reduce the diameter of the propeller. The reduction in the diameter of the downstream propeller makes it possible to reduce noise caused by vortices generated by the upstream propeller.

Claims

1-9. -9. (canceled)

10. A turbine engine comprising:

two coaxial and contra-rotating unducted external fans, respectively of an upstream and a downstream fan,

wherein a length of blades of at least one of the two fans can be varied such that the diameter of the downstream fan is less than the diameter of the upstream fan.

11. The turbine engine as claimed in claim 10, in which blades of the downstream fan are retractable along their longitudinal axis, so as to reduce the diameter of the downstream fan.

12. The turbine engine as claimed in claim 10, in which the variable-length blades are telescopic with at least two blade elements which nest one inside the other and can slide one relative to the other along the axis of the blade.

13. The turbine engine as claimed in claim 12, in which the two blade elements mounted so as to slide one relative to the other are formed at the tip of the blades.

14. The turbine engine as claimed in claim 12, in which the two blade elements are formed at a root end of the blades.

15. The turbine engine as claimed in claim 10, in which at least the blades of the downstream fan are variable-pitch blades.

16. A method for reducing noise emitted by a turbine engine including two coaxial and contra-rotating unducted external fans, respectively of an upstream and a downstream fan, during a phase of operation of this engine, the method comprising:

modifying a length of the blades of at least one fan so that the diameter of the downstream fan is less than that of the upstream fan during the phase of operation.

17. The method as claimed in claim 16, the turbine engine being mounted on an aircraft, the phases of operation corresponding to take-off and landing of the aircraft.

18. The method as claimed in claim 16, whereby the reduction in blade length is compensated for by increasing loading on the blade, by varying a blade pitch angle.