Patent Publication Number: US-8985518-B2

Title: Air guiding means for a dispenser

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is the national phase under 35U.S.C. §371 of PCT/SE2009/050717 filed 11 Jun. 2009. 
     TECHNICAL FIELD 
     The present invention relates to an air guiding means for a dispenser. 
     BACKGROUND ART 
     Dispenser units arranged to dispense countermeasures from aircrafts are well known. Both fighter and transport aircrafts, as well as civil aircrafts are exposed for threats from self-guided missiles equipped with radar, IR or laser sensors, which can be fired either from other aircrafts or from the ground. In order to protect the threatened aircrafts from an attack of such missiles they are provided with various types of dispenser units which dispense countermeasure means. Such countermeasure means may comprise aluminized foil or fibers, pyrophoric IR materials, flares and also laser-reflecting fibers or foils, which confuse and divert missiles aimed at the aircraft. 
     Document EP-A1-0511946 discloses a dispenser for feeding out packages containing chaff, which dispenser may be arranged on an aircraft. The dispenser is provided with air guiding means in order to create a pressure difference at a feeding out opening pulling out the packages in the air stream behind the dispenser. The air guiding means are air scoops provided with an air inlet in connection to the side of the dispenser and an air outlet in connection to the feeding out opening. 
     Commonly, the dispenser is applied on the under side of an aircraft, preferably an airplane, and has an elongated body shape with its longitudinal direction coinciding with the flight direction of the air craft. The elongated body is exposed to air streaming having a speed corresponding to the flight speed of the aircraft. The feeding out opening of a magazine for packages provided with chaffs terminates in the rear section of the dispenser. During a flight a wake is formed behind the feeding out opening. Immediately behind the dispenser, the wake has a sectional area of the same order of magnitude as the sectional area of the dispenser. The formation of this wake inter alia influences on the separation time of the packages with chaffs, which is the time required for the package located closest to the feeding out opening to separate from the rest of the packages in the magazine and to leave the feeding out opening. 
     However, the packages containing chaff are only fed out at moments when the aircraft is under attack or at moments when the aircraft is under a potential threat. Therefore, the air guiding means in form of air scoops have no function when the dispenser is inactivated and the packages containing chaff are not fed out from the dispenser. During a mission the feeding out packages containing chaff takes place under a relatively short period of time in relation to the overall flight time of the mission. As a result, the need of the air scoops is only limited to a relatively short period of time in relation to the overall flight time of the mission. 
     The air scoops have a negative influence on the air drag and therefore the fuel consumption of the aircraft will increase. As a result, the operation range of the aircraft will decrease when the fuel consumption increases. Also, the air scoops could create noise which may be detected by an enemy in order to detect the position of the aircraft. 
     The objective problem to be solved by the present invention is therefore to reduce the air drag of the air scoops when the dispenser is not activated. 
     Another objective problem to be solved by the present invention is to reduce noise created by the air scoops when the dispenser is not activated. 
     SUMMARY OF THE INVENTION 
     The above-mentioned objects are achieved by an air guiding means for a dispenser. 
     When controlling the air stream by means of the control means through the air scoops there is a possibility to reduce the air drag from the air scoops when the dispenser is not activated. Therefore, there is also a possibility to increase the operation range of the aircraft. Also, there is a possibility to reduce or even to eliminate the noise created by the air scoops when the dispenser is not activated. 
     According to a first embodiment of the invention the control means is arranged to move the air scoop in order to open and close the air inlet. When the dispenser is not activated the air scoop can be moved to a position in relation to the body of the dispenser where the air drag is reduced. 
     According to a second embodiment of the invention a deflector means is connected to the control means and the control means is arranged to move the deflector means in order to open and close the air inlet. When the dispenser is not activated the deflector means can be moved to a position in relation to the body of the dispenser where the air drag is reduced. 
     The control means can be of any type of power generating means such as a pneumatic cylinder, hydraulic cylinder and/or an electrical motor. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further advantages and features of the invention can be derived from the following detailed description of exemplary embodiments of the invention, with reference to the drawings. 
         FIG. 1  shows a view from above of a first embodiment of an air guiding means for a dispenser according to the present invention in which the air guiding means are brought to a position when the dispenser is not activated, 
         FIG. 2  shows a view from above of the first embodiment of the air guiding means for the dispenser according to the present invention in which the air guiding means are brought to a position when the dispenser is activated, 
         FIG. 3  shows a view from above of a second embodiment of an air guiding means for a dispenser according to the present invention in which deflector means are brought to a position when the dispenser is not activated, and 
         FIG. 4  shows a view from above of the second embodiment of the air guiding means for a dispenser according to the present invention in which the deflector means are brought to a position when the dispenser is activated. 
         FIG. 5  shows a side view of an aircraft on which a dispenser provided with air guiding means according to the present invention is arranged. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows a view from above of a first embodiment of an air guiding means  1  for a dispenser  2  according to the present invention in which the air guiding means  1  are brought to a position when the dispenser  2  is not activated. The air guiding means  1  comprises at least one air scoop  4  to guide an air stream  6  to a feeding out opening  8  for packages of chaff  10  on the dispenser  2  in order to facilitate the packages  10  to be released from the dispenser  2 , which is described above. According to the embodiment disclosed in  FIG. 1  two air scoops  4  are arranged at the body  12  of the dispenser  2 . Also, suspension means  14  are arranged on the body  12  of the dispenser  2  for suspending the dispenser  2  on an aircraft  16 , which is described in connection to  FIG. 5  below. 
     A control means  18  is provided for controlling the air stream  6  through the air scoops  4 . The control means  18  can be a pneumatic cylinder, hydraulic cylinder and/or an electrical motor. According to the disclosed embodiment one control means  18  is arranged to control both air scoops  4 . However, it is also possible to arrange a separate control means  18  for each air scoop  4 . 
       FIG. 2  shows a view from above of the first embodiment of the air guiding means  1  for the dispenser  2  according to the present invention in which the air guiding means  1  are brought to a position when the dispenser  2  is activated. It should be understood that when the dispenser  2  is activated the dispenser  2  is ready to dispense packages of chaffs  10 . In this activated position the air scoops  4  guide the air stream  6  to the feeding out opening  8  for chaffs. Each air scoop  4  comprises an air inlet  20  and an air outlet  22 . As disclosed in  FIG. 2  the air inlet  20  is exposed for the air stream  6  which is created when the aircraft  16  is in the air and has an operation speed. The air stream  6  enters the air inlet  20 , is guided approximately 90 degrees by the air scoops  4  and leaves the air outlet  22  which is situated at the feeding out opening  8  for the chaffs. When the dispenser  2  is activated and packages of chaffs  10  are to be dispensed the air scoops  4  are put into the position by the control means  18  in order to direct the air stream  6  to the feeding out opening  8  for the chaffs. The directed air steam  6  creates a pressure difference behind the dispenser  2  at the feeding out opening  8  for the chaffs, which pressure difference acts to remove the packages of chaffs  10  released at the feeding out opening  8 . This results in a reduced separation time and a distinct separation of chaffs which may be dispensed in a subsequent order. 
     The control means  18  is arranged to close and open the air inlet  20  in order to controlling the air stream  6  trough the air scoops  4 . When controlling the air stream  6  by means of the control means through the air scoops  4  there is a possibility to reduce the air drag from the air scoops  4  when the dispenser  2  is not activated. As a result, there is also a possibility to increase the operation range of the aircraft  16 . Also, there is a possibility to reduce or even to eliminate noise created by the air scoops  4  when the dispenser  2  is not activated. Hence, the air inlet  20  is so closed that the air drag from the air stream  6  is reduced in relation to when the air inlet  20  is opened. According to the first embodiment the control means  18  is so arranged to move the air scoops  4  in order to open and close the air inlet  20 . As disclosed in  FIG. 1  the control means  18  is so arranged to move the air scoops  4  into a position where the air inlet  20  is closed by the body  12  of the dispenser  2 . The air scoops  4  are hidden behind the body  12  of the dispenser  2 , so that the air stream  6  will pass the dispenser  2  without entering the air inlet  20  of the air scoops  4  thereby avoiding the energy loss otherwise experienced when deflecting an air stream  6  through the air scoop  4 . 
       FIG. 3  shows a view from above of a second embodiment of an air guiding means  1  for a dispenser  2  according to the present invention in which deflector means  24  are brought to a closing position of the air inlets  20  when the dispenser  2  is not activated. I this embodiment two deflector means  24  are connected to the control means  18  and the control means  18  is arranged to move the deflector means  24  in order to open and close the air inlet  20 . 
     Preferably each deflector means  24  are a part of a wall section  26  of the dispenser body  12 . However, the deflector means  24  may also be separate wall sections  26  arranged on the outside of the body  12  of the dispenser  2 . The deflector means may be pivotally hinged to the dispenser body  12  by means of hinges  28 . 
       FIG. 4  shows a view from above of the second embodiment of the air guiding means  1  for a dispenser  2  according to the present invention in which the deflector means  24  are brought to a position when the dispenser  2  is activated. 
       FIG. 5  shows a side view of an aircraft  16  on which a dispenser  2  provided with air guiding means  1  according to the present invention is arranged. The dispenser  2  may be suspended under a wing  30  or under the fuselage  32  of the aircraft  16 . 
     First electrical terminals  34  are arranged at the suspension means  14 , which are connected to a first control system  36  for controlling the dispenser  2 . When arranging the first electrical terminals  34  at the suspension means  14  of the dispenser  2  electrical power and control signals can be supplied to the first control system  36  and to the dispenser  2 . The first electrical terminals  34  are adapted to mate with second electrical terminals  38  on a hard point  40  on the aircraft  16 . As a result a transmission of power and control signals between the aircraft  16  and the dispenser  2  is possible. The first control system  36  is adapted to communicate with a second control system  42  on the aircraft  16 . The first control system  36  of the dispenser  2  is connected to the control means  18  for controlling the air stream  6  through the air scoops  4 . Thus, when packages of chaffs  10  are to be dispensed from the dispenser  2  signals are sent from the first control system  36  of the dispenser  2  to the control means  18  in order to move the air scoops  4  according to the first embodiment or to move the deflector means  24  according to the second embodiment. 
     Parts and details of the different embodiments may be combined and arranged together.