Variable geometry nozzle

A variable geometry nozzle operable in ambient air and having a flow-through passage and being settable in a cruise setting and an attenuation setting and being operable in a cruise mode and an attenuation mode, said nozzle comprising:

• a first, sleeve type rotary valve,
• a second, face type rotary valve,
• means for setting said nozzle in said cruise setting and said supression setting,
• said first valve providing passages from said ambient air into said flow-through passage,
• said second valve providing passages from said flow-through channel to said ambient air,
• said first and second valves being open in said attenuation setting and closed in said cruise setting,
• whereby in said attenuation setting said passages provided by said first valve allow flow from said ambient air into said flow-through passage and said passages provided by said second valve allow flow from said flow-through passage to said ambient air and in said cruise setting all said passages are closed off.

A variable geometry nozzle for a jet engine having an attenuation setting and a cruise setting and being operable in a sound attenuation mode and a cruise mode and having an outflow end, said nozzle comprising first and second rotary valves,

• said nozzle having a gas flow passage and comprising a fixed portion and a movable portion surrounding said passage, said fixed and movable portion being essentially cylindrical,
• said fixed portion being attached to said outflow end and having a first cylindrical wall having an outside diameter, a first forward end, first aft end, an aft planar face, a first length and a first plurality of first openings in said first wall, said first openings being spaced radially equidistant from each other and having first spaces between them,
• said first spaces having first widths and said first openings having second widths, said first and second widths being essentially equal,
• said first openings being provided with lobes extending from said first wall into said passage and having exit faces coplanar with said aft face,
• said movable portion having a second length, a forward segment and an aft segment, said forward segment having a cylindrical wall having an inside diameter, a second forward end having a planar face, a third length equal to said first length, said aft segment having a wall which is a surface of revolution, said forward and aft sections joining in a plane of adjoinment which is perpendicular to said second cylindrical wall,
• said inside diameter being greater than said outside diameter by an amount in the range of 0.1 to 1% of said outside diameter,
• said second plurality of openings being in said forward segment and spaced radially equidistant from each other and having second spaces between them, said second openings having third widths and said second spaces having fourth widths, said third and fourth widths being essentially equal,
• said third plurality of openings being in said aft segment and spaced radially equidistant from each other and having third spaces between them, said third openings having fifth widths and said third spaces having sixth widths, said fifth and sixth widths being essentially equal,
• said second openings being provided with lobes extending outwardly from said second cylindrical wall and having entrance faces coplanar with said forward face,
• said third openings being provided with lobes extending into said passage and having entrance faces coplanar with said plane of adjoinment,
• said third openings being in longitudinal alignment with said second spaces in said forward segment,
• said second portion being rotatably attached to said fixed portion with said forward segment telescopically surrounding said fixed portion, whereby said first openings and said second openings are positioned relative to each other to function as said first rotary valve and said exit faces of said lobes provided on said first openings and said entrance faces of said lobes provided on said third openings are positioned relatively to cooperate in said plane of adjoinment to function as said second rotary valve,
• means being provided to rotate said movable portion relative to said fixed portion interchangeably between said suppression setting and said cruise setting,
• whereby with said movable portion set in said attenuation setting:
• said first and second openings are coincident and they, in conjunction with said lobes provided for said openings, provide passages for said ambient air to flow from outside said nozzle into said passage and said lobes provided on said second openings and said second openings provide passages for gas flow from said passage through said second wall into said ambient air and with said rotary valves being open said nozzle is operable in said sound attenuation mode, and
• with said movable portion set in said cruise setting:
• said second openings are aligned with said first spaces and said exit faces of
• said lobes provided on said first openings are aligned in said plane of adjoinment with said entrance faces of said lobes provided on said third openings, so that both rotary valves are closed and said nozzle is in said cruise mode.