Static structures (e.g. – buildings) – With traffic-guiding feature
Reexamination Certificate
2002-04-03
2003-05-13
Friedman, Carl D. (Department: 3637)
Static structures (e.g., buildings)
With traffic-guiding feature
C181S144000, C073S147000
Reexamination Certificate
active
06560936
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 incorporating improvements in the disposition of an air inlet structure, the construction of the ceiling of a test chamber, and construction of an 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 air 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 313399/2000, the ceiling of the noise control hangar is at a level above that of the tip of the vertical tail fin of the aircraft to enable the high vertical tail fin move under the ceiling. Therefore, the noise control hangar inevitably has a useless space in an upper region of the test chamber. Since the noise control hangar is not provided with any current straightening plates or the like for straightening air currents flowing in the useless space, the exhaust gas discharged from the engine tends to flow forward through the useless space in the test chamber, and air currents are liable to produce eddies and turbulent flows. Consequently, the exhaust gas is liable to be sucked into the engine of the aircraft and hence it difficult to carry out the run-up of the engine of the aircraft under proper conditions.
Although the circulation-preventive plates are disposed slightly in front of the tail fins of the aircraft, the exhaust gas tends to flow forward and whirling currents are liable to be produced in a region in front of the circulation-preventive plates because the large useless space extends on the front side of the circulation-preventive plates.
Since the exhaust gas produced in this noise control hangar is discharged from the back end of the test chamber directly into the exhaust line, the exhaust gas currents is accompanied by a large amount of accompanying currents, i.e., an amount as large as about four times the amount of the exhaust gas currents, during the run-up of the engine. However, any accompanying currents capable of preventing the reverse flow of the exhaust gas cannot be produced because the nose control hangar is not provided with any current straightening means for making the accompanying currents flow regularly backward.
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, to provide an aircraft engine run-up hangar capable of making an exhaust gas flow from a test chamber directly into an exhaust passage, and to provide an aircraft engine run-up hangar capable of producing accompanying currents capable of preventing the reverse flow of an exhaust gas in a test chamber.
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, a ceiling included in the building has an inclined section sloping down backward to straighten air currents, and, a groove is formed in a middle part, with respect to the width, of the inclined section to permit the vertical tail fin of an aircraft to pass when the aircraft is carried into or out of the test chamber.
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 exhaust structure is connected to the rear end part of the building so as to form the exhaust passage extending obliquely upward from the back end of the building, any
Akimoto Kazuyuki
Hirakawa Hajime
Kawashima Takashi
Ogawa Kazushi
Saito Yasuo
Amiri Nahid
Friedman Carl D.
Kawasaki Jukogyo Kabushiki Kaisha
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