Low drag inlet design using injected duct flow

A selective drag reduction air vehicle disposed in an exterior airflow comprising a turbo engine comprising:

• an engine housing;
• an air inlet member for receiving engine intake air disposable within said engine housing;
• a first air exit port disposed in fluid communication with said air inlet member, adapted to direct intake air from said air inlet member and to direct intake air substantially in the direction of exterior airflow, to reduce the external engine boundary layer separation drag;
• a second air exit port disposed in fluid communication with said air inlet member, adapted to direct intake air from said air inlet member and to direct intake air substantially in a direction perpendicular to the exterior airflow, to reduce the external engine friction drag;
• and
• a control device for regulating intake airflow through said first and second air exit ports in response to sensed external engine conditions to mitigate at least one of the external engine boundary layer separation drag and the external engine friction drag.

A turbo engine disposed in an exterior airflow which selectively reduces external engine boundary layer separation drag and external engine friction drag comprising:

• an engine housing;
• an air inlet member for receiving engine intake air disposable within said engine housing;
• a first air exit port disposed in fluid communication with said air inlet member, adapted to direct intake air from said air inlet member and to direct intake air substantially in the direction of exterior airflow, to reduce the external engine boundary layer separation drag;
• a second air exit port disposed in fluid communication with said air inlet member, adapted to direct intake air from said air inlet member and to direct intake air substantially in a direction perpendicular to the exterior airflow, to reduce the external engine friction drag;
• and
• a control device for regulating intake airflow through said first and second air exit ports in response to sensed external engine conditions to mitigate at least one of the external engine boundary layer separation drag and the external engine friction drag.

A turbo engine housing disposed in an exterior airflow which selectively reduces boundary layer separation drag and friction drag comprising:

• an air inlet member for receiving engine intake air;
• a first air exit port disposed in fluid communication with said air inlet member, adapted to direct intake air from said air inlet member and to direct intake air substantially in the direction of exterior airflow, to reduce the external engine boundary layer separation drag;
• a second air exit port disposed in fluid communication with said air inlet member, adapted to direct intake air from said air inlet member and to direct intake air substantially in a direction perpendicular to the exterior airflow, to reduce the external engine friction drag;
• and
• a control device for regulating intake airflow through said first and second air exit ports in response to sensed external engine conditions to mitigate at least one of the external engine boundary layer separation drag and the external engine friction drag.

A turbo engine noise reduction system disposable in an air vehicle turbo engine housing disposed in an exterior airflow for reducing external engine drag on the engine housing comprising:

• an air inlet member for receiving engine intake air disposable within said engine housing, comprising a plurality of intake air noise reduction cells;
• an air exit port disposed in fluid communication with said air inlet member, said air exit port comprising first and second portions, said first portion disposed in fluid communication with said air inlet member, adapted to direct intake air from said air inlet member and to direct intake air substantially in the direction of exterior airflow, to reduce external engine boundary layer separation drag, and said second portion disposed in fluid communication with said air inlet member, adapted to direct intake air from said air inlet member and to direct intake air substantially in a direction perpendicular to the exterior airflow, to reduce external engine friction drag;
• and
• a control device for regulating intake airflow through said exit ports in response to sensed external engine conditions to mitigate the external engine drag.

A method for reducing turbo engine noise while reducing engine drag on an engine housing disposed in an exterior airflow comprising the following steps:

• (a) forming an air inlet member for receiving engine intake air disposable within said engine housing, the air inlet member comprising a plurality of noise reduction cells, the noise reduction cells defining a maximum cross sectional air flow area, the air inlet member further comprising a plurality of pressure conduits, the noise reduction cells corresponding to and in fluid communication with respective ones of the pressure conduits, the pressure conduits defining a maximum cross sectional airflow area, and the maximum cross sectional airflow area of each of the noise reduction cells being greater than the maximum cross sectional airflow area of each of the pressure conduits;
• (b) forming an air exit port disposed in fluid communication with said air inlet member to reduce the external engine drag, said air exit port being formed into a first exit portion and a second exit portion;
• 1) said first exit portion being formed to direct intake air from said pressure conduits and to direct intake air substantially in the direction of exterior airflow, to reduce external engine boundary layer separation drag;
• and
• 2) said second exit portion formed to direct intake air from said pressure conduits and to direct intake air substantially in a direction perpendicular to the exterior airflow,;
• and
• (c) regulating intake airflow through said air exit port in response to sensed external engine conditions to mitigate the external engine drag.

A method for selectively reducing turbo engine boundary layer separation drag and friction drag on an engine housing disposed in an exterior airflow comprising the following steps:

• (a) forming an air inlet member for receiving engine intake air disposable within said engine housing;
• (b) forming a first air exit port disposed in fluid communication with said air inlet member, adapted to direct intake air from said air inlet member and to direct intake air substantially in the direction of exterior airflow, to reduce the external engine boundary layer separation drag;
• (c) forming a second air exit port disposed in fluid communication with said air inlet member, adapted to direct intake air from said air inlet member and to direct intake air substantially in a direction perpendicular to the exterior airflow, to reduce the external engine friction drag;
• and
• (d) regulating intake airflow through said first and second air exit ports in response to sensed external engine conditions to mitigate at least one of the external engine boundary layer separation drag and the external engine friction drag.