Patent Application
20210339844
This application claims the benefit of the European patent application No. 20382351.3 filed on Apr. 29, 2020, the entire disclosures of which are incorporated herein by way of reference.
The present invention refers to a rear end for an aircraft including a boundary layer ingestion (BLI) engine adapted to operate as a thruster with the aid of a movable control surface, mounted after the exhaust of the BLI engine to modulate the flow and divert it in order to provide vector thrust.
The NASA STARC-ABL aircraft concept has a Boundary Layer Ingestion propulsion, where a conventional small engine (electric or thermal) drives a fan or rotor located at the end of a conical aft fuselage. This aircraft concept exhibits a T-tail. The European version of this project, known as CENTRELINE, is almost identical to the STARC-ABL concept.
The NASA/MIT D8 aircraft exhibits a Boundary Layer Ingestion propulsive system on a flattened rear fuselage. In this case, the empennage is of a “Pi” tail configuration, and the engines installed at the rear end are primary propulsive engines installed to only ingest the boundary layer on the upper surface of the fuselage.
Regarding thrust vectoring, there are several concepts and applications known in the prior art but none of them is related to an engine that also operates as a BLI engine.
It would therefore be desirable to provide a technical solution that provides both an increase of the propulsive efficiency and thrust vectoring through the use of a BLI engine.
The present invention overcomes the above mentioned drawbacks by providing a rear end section for an aircraft adapted to perform boundary layer ingestion at the time that provides vectoring thrust to the aircraft.
A main object of the present invention is to provide a rear end for an aircraft that is able of increasing the propulsive efficiency of conventional aircrafts, by ingesting the slow air in the fuselage boundary layer into some fluid mechanic thrusting devices, to increase the aircraft velocity, and reduce its usual energy consumption.
Another object of the invention is to reduce the size of the rear end of an aircraft.
The rear end section for an aircraft has a fuselage, a v-tail formed by two surfaces set in a v-shaped configuration, and a thruster assembly mounted on the rear end fuselage between the v-tail and the rearmost section of the rear end fuselage. The thruster assembly comprises at least one propulsion device installed to ingest the air from the boundary layer formed over the fuselage of the aircraft, a control surface attached at the rearmost section of the rear end, and a casing covering at least part of the propulsion device such that an air inlet and an air outlet are defined between the casing and the propulsion device. The air inlet is designed for the passage of the fuselage boundary layer towards the propulsion device, and the air outlet is designed for directing the airflow exhausted from the propulsion device towards the control surface, to divert the airflow in order to provide vectoring thrust for the aircraft.
The invention provides an aircraft rear end with a propulsion device (engine) operating both as a BLI engine, by ingesting and consuming air forming a boundary layer over the fuselage of the aircraft, and also as a vectoring thruster with the aid of a control surface mounted to receive the engine slipstream, blowing over the control surface.
The invention increases the propulsive efficiency of the aircraft, and thus decreases its fuel consumption. The increment in linear momentum of the air of the boundary layer effected by the BLI engine generates thrust, but the air in the slipstream has a lower velocity than it would be required to have in order to impart this momentum jump to free-stream air, thus leaving less kinetic energy in the slipstream and helping to reduce the energy consumption to generate a given amount of thrust.
Preferably, the at least one propulsion device will comprise an array of engines in order to improve the boundary layer capture efficiency, and to reduce the size and cost of each of the engines.
Additionally, using the BLI concept and adapting it to produce thrust vectoring, allows reducing the size of the empennage, with a consequent reduction of weight, drag and cost of the aircraft.
For a better comprehension of the invention, the following drawings are provided for illustrative and non-limiting purposes, wherein:
As seen in
The propulsion device (5) is installed to ingest and consume air forming the fuselage boundary layer. The control surface (6) is mounted at the rearmost section of the rear end to receive the exhaust (outflow) of the propulsion device (5), and thus provide vectoring thrust to the aircraft when the control surface (6) is deflected. The casing (7) is designed to cover at least part of the propulsion device (5) to allow both the passage of the fuselage boundary layer towards the propulsion device (5) through the air inlet (8), and the passage of the airflow exhausted from the propulsion device (5) towards the control surface (6) through the air outlet (9).
As shown in
According to another preferred embodiment, the control surface (6) is rotatably attached to the rearmost section of the rear end to provide a pitching movement to the aircraft. The technical advantage of this vectored thrust is to reduce the size of the empennage.
Finally, as shown in
While at least one exemplary embodiment of the present invention(s) is disclosed herein, it should be understood that modifications, substitutions and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of this disclosure. This disclosure is intended to cover any adaptations or variations of the exemplary embodiment(s). In addition, in this disclosure, the terms “comprise” or “comprising” do not exclude other elements or steps, the terms “a” or “one” do not exclude a plural number, and the term “or” means either or both. Furthermore, characteristics or steps which have been described may also be used in combination with other characteristics or steps and in any order unless the disclosure or context suggests otherwise. This disclosure hereby incorporates by reference the complete disclosure of any patent or application from which it claims benefit or priority.
| Number | Date | Country | Kind |
|---|---|---|---|
| 20382351.3 | Apr 2020 | EP | regional |
