Static structures (e.g. – buildings) – Wall – ceiling – floor – or roof designed for ventilation or...
Reexamination Certificate
2002-04-03
2003-10-28
Friedman, Carl D. (Department: 3635)
Static structures (e.g., buildings)
Wall, ceiling, floor, or roof designed for ventilation or...
C052S174000, C052S198000, C454S262000, C454S906000, C454S237000, C454S241000, C454S242000
Reexamination Certificate
active
06637168
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an aircraft engine run-up hangar and, more specifically, to an aircraft engine run-up hangar having an improved air inlet structure through which fresh air is taken into a test chamber, an improved current-straightening structure disposed near the air inlet structure, and an improved exhaust structure through which gases are discharged from the test chamber, and capable of producing stable air currents in the test chamber.
2. Description of the Related Art
An overhauled aircraft engine or an aircraft engine of an aircraft to be placed in commission is subjected to a ground run-up in an open space for performance test. Various noise control measures have been taken for environmental protection. Generally, a noise-suppressing duct is disposed just behind the exhaust cone of the engine for outdoor run-up. Some recent run-up method uses a building capable of entirely housing an aircraft therein and having a noise control function, which is called a noise control hangar. Generally, an air inlet structure included in a noise control hangar is incorporated into the front end part of the noise control hangar to take air into the noise control hangar. Such a noise control hangar of a front air inlet type is provided with a big door provided with an inlet structure having current-straightening and noise control functions at its front end. This big door must be opened when carrying an aircraft into or out of the noise control hangar. The air inlet structure having current-straightening and noise control functions is inevitably long and, consequently, the big door provided with the long air inlet structure is inevitably very thick. The thickness of a big door included in a practical noise control hangar of a front inlet type is as big as 7.5 m.
Operations for opening and closing the big door provided with the air inlet structure and having a big thickness to carry an aircraft into or out of the noise control hangar need a large-scale door operating mechanism, and a large operating space is necessary for moving and storing the big door provided with the air inlet structure. Thus, the thick big door and the large operating space increase equipment costs. Moreover, the air inlet structure provides a large intake resistance and hence the back flow of exhaust gas is liable to occur in the noise control hangar. If wind blows outside across a direction in which air flows into the air inlet, it is difficult to produce uniform air currents by straightening air taken in through the air inlet and hence it is difficult to carry out the run-up of the aircraft engine under proper run-up conditions.
A previously proposed noise control hangar is provided with an air inlet in a front end part of the roof structure of the noise control hangar instead of in the front end of the noise control hangar. A noise control hangar proposed in, for example, JP-A 318696/2000 is provided with an air inlet formed in a front end part of the roof structure of the noise control hangar corresponding to the front end part of the noise control hangar, and an exhaust duct to be connected to the exhaust port of an aircraft engine and placed in the test chamber defined by the noise control hangar. Exhaust gas discharged from the aircraft engine is discharged outside through an exhaust line arranged in a back end part of the noise control hangar during the run-up of the aircraft engine. The exhaust duct must be moved every time aircrafts are changed and much labor is necessary for moving the exhaust duct. A noise control hangar disclosed in JP-A 313399/2000 has a roof structure provided with an inlet opening in a front end part thereof corresponding to the front end part of the noise control hangar, and is provided with an exhaust line extending backward and upward from the back end of a test chamber, and circulation-preventive plates having a J-shaped cross section disposed on a part of a ceiling in a back part of the test chamber to prevent the circulation of the exhaust gas.
In the prior art noise control hangar disclosed in JP-A 318696/2000, air currents flowing through the air inlet formed in the roof structure into the test chamber impinge on the floor of the test chamber and then flow backward. Thus, the downward air currents flowing through the air inlet into the test chamber cannot be regularly deflected so as to flow backward toward the aircraft and most part of the air currents is liable to produce eddies and turbulent flows, making it difficult to carry out run-up under proper run-up conditions.
Since the height of the vertical tail fin of an aircraft is greater than that of main wings holding wing engines, the height of the ceiling of a noise control hangar must be greater than that of the vertical tail fin. In such a noise control hangar, the exhaust gas discharged backward from the engine tends to flow forward through an upper region of a space defined by the noise control hangar and hence the exhaust gas is liable to be sucked into the engine, which makes it difficult to carryout the run-up of the engine under proper run-up conditions.
The noise control hangar disclosed in JP-A 313399/2000 has the air inlet formed in the front end part of the roof structure and provided with a current-straightening structure including a plurality of vertical plates longitudinally arranged at predetermined intervals. This noise control hangar has the following problems because any other current-straightening means is not disposed near the air inlet. The upper end of the air inlet is exposed on the roof structure to enable fresh air to flow directly into the air inlet. Under a stormy condition, air is unable to flow uniformly through the air inlet, eddies are liable to be produced in air currents and air currents are liable to be disturbed. Since the current-straightening structure disposed at the air inlet includes the plurality of plates, eddies and turbulence are liable to remain in the air currents below the current-straightening structure.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide an aircraft engine run-up hangar including a building defining a test chamber and having a roof structure provided with an air inlet, capable of deflecting air currents flowing through the air inlet into the building toward an aircraft housed in the building and of satisfactorily straightening air currents flowing through the air inlet into the building, and not requiring any exhaust duct in a test chamber defined by the building.
According to the present invention, an aircraft engine run-up hangar includes: a building defining a test chamber capable of receiving an aircraft therein; an air inlet structure; and an exhaust structure; wherein the air inlet structure is formed in a front end part of a roof structure corresponding to a front end part of the building, the exhaust structure is connected to a rear end part of the building and defines an exhaust passage extending obliquely upward from the back end of the building, and one or a plurality of current deflecting members are disposed near a lower end of the air inlet structure to deflect air currents flowing through the air inlet structure into the building toward an aircraft housed in the building.
The air inlet structure is disposed on the roof structure and hence a large door for closing a large opening through which the aircraft is carried into or out of the building does not need to be provided with any air inlet structure, and the large door may be of simple construction similar to that of an ordinary soundproof door. Therefore any space for moving and storing the large door is not necessary, which is favorable to saving space necessary for installing the aircraft engine run-up hangar and is convenient in incorporating various current-straightening means into the air inlet structure. Since the air inlet structure is disposed on the front end part of the roof structure corresponding to the front end part of the building, air currents introduced through the ai
Akimoto Kazuyuki
Hirakawa Hajime
Kawashima Takashi
Ogawa Kazushi
Saito Yasuo
Amiri Nahid
Friedman Carl D.
Kawasaki Jukogyo Kabushiki Kaisha
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