Abstract:
A fairing system developed to reduce the flow disturbance around sensor elements allowing accurate measurement of the pressure distribution on an airplane exterior surface. The fairing also protects the sensors and electronics of the pressure belt from direct exposure to airflow.

Description:
BACKGROUND  
       [0001]     1. Field of the Invention  
         [0002]     This invention relates generally to a fairing system developed to reduce the flow disturbance around sensor elements allowing accurate measurement of the pressure distribution on an airplane exterior surface.  
         [0003]     2. Related Art  
         [0004]     The ability to measure the pressure distribution across an airplane external surface is a requirement for Flight Test. To measure pressure distribution tubing has been glued to the external surface and plumbed to pressure sensors positioned in a remote location. This solution has proved to be labor intensive, expensive to install and troublesome to maintain.  
         [0005]     A sensor pressure belt has been developed which locates the sensor at the required measurement location. For example, in U.S. Pat. No. 6,134,485, a system and method for analyzing physical parameters of flight data is described, which includes a multi-sensor system having an array of belts. Each belt includes a plurality of interconnected belt segments including a substrate having an electrically conductive digital data bus, and at least one module having a first sensor, a second sensor and a digital signal processor, and a coating for protecting the belt segment. The first and second sensors, which are preferably formed as micro-electromechanical sensors sharing a common substrate, respectively generate signals representative of a first physical parameter and a second physical parameter. The processor receives and analyzes the first and second signals to generate a third signal. The third signal is transmitted along the electrically-conductive bus to a remotely-located controller. The controller analyzes the third signal to obtain flight status information relating to the effect of the physical parameters on the flight. U.S. Pat. No. 6,134,485 is incorporated herein by reference. Unfortunately, the pressure belt is not suitable to be exposed directly to airflow.  
         [0006]     Accordingly, what is needed is a mechanism to protect the sensors, create a smooth aerodynamic surface over the pressure belt and maintain the integrity of the installation in flight.  
       SUMMARY  
       [0007]     This invention provides a fairing system developed to reduce the flow disturbance around sensor elements allowing accurate measurement of the pressure distribution on an airplane exterior surface. The fairing also protects the sensors and electronics of the pressure belt from direct exposure to airflow.  
         [0008]     The fairing system includes a fairing assembly that can include shim stock and a thin rubber pad or substrate. The fairing assembly is configured to cover a sensor pressure belt, contour to the electronics on the belt and provide access at appropriate locations to allow for the measurement of pressure.  
         [0009]     The fairing assembly is shaped such that when installed on the airplane surface it minimizes the flow disturbance across the pressure sensing element allowing an accurate measurement of the local pressure. The fairing assembly is attached to the airplane surface using conventional methods, such as tape for ease of installation.  
         [0010]     In one aspect of the invention, a fairing system is provided which includes a multisensor system for measuring physical parameters at a plurality of discrete locations about a surface of an object; and a fairing assembly including an aerodynamically configured surface having a central access portion in which the multisensor system is disposed. The fairing assembly provides environmental access to the multisensor system to measure local pressure on the surface.  
         [0011]     In yet another aspect of the invention, a method is provided for assembling a fairing system. The method includes positioning a pressure sensing element at a measurement location on an object surface; positioning a substrate over the pressure sensing element; bonding a CRES sheet to the substrate; and forming a pressure port hole to provide environmental access to the pressure sensing element; and positioning a fairing body over the pressure sensing element, the substrate and the CRES sheet.  
         [0012]     The fairing system and installation method reduce installation flow time during an airplane test program. The fairing makes the airplane installation of the pressure belts efficient and thus reduces flight test costs.  
         [0013]     Additional advantages, objects, and features of the invention will be set forth in part in the detailed description which follows. It is to be understood that both the foregoing general description and the following detailed description are merely exemplary of the invention, and are intended to provide an overview or framework for understanding the nature and character of the invention as it is claimed. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]     The accompanying drawings are included to provide further understanding of the invention, illustrate various embodiments of the invention, and together with the description serve to explain the principles and operation of the invention. In the drawings, the same components have the same reference numerals. The illustrated embodiment is intended to illustrate, but not to limit the invention. The drawings include the following Figures:  
         [0015]      FIG. 1  is a simplified top view of the fairing system in accordance with an embodiment of the present invention;  
         [0016]      FIG. 2  is a simplified sectional view of the fairing system of  FIG. 1  in accordance with an embodiment of the present invention;  
         [0017]      FIG. 3  is a simplified sectional view of the fairing system of  FIG. 1  in accordance with an embodiment of the present invention; and  
         [0018]      FIG. 4  is a flowchart describing an assembly method of forming the fairing system on the surface of an object in accordance with an embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION  
       [0019]      FIG. 1  is a simplified view of fairing system  100  in accordance with an embodiment of the present invention. Fairing system  100  includes a fairing assembly  102  having an outer fairing body  104  defined by aero wedges  106  and  108  formed about a central access portion  110 . Fairing assembly  102  also includes a substrate  206  and CRES (corrosion resistant steel) sheet  208 . Generally, disposed within central access portion  110  is at least one pressure sensing element  112  for analyzing physical parameters of flight data. In one embodiment, pressure sensing element  112  is coupled to belt segment  114 , which locates at least one pressure sensing element  112  at the required measurement location.  
         [0020]     Fairing assembly  102  is configured to cover pressure sensing element  112  and belt segment  114  by being made to contour to the electronics on belt segment  114 . Fairing assembly  102  provides access at appropriate locations to allow for the measurement of pressure.  
         [0021]     Fairing body  104  is shaped such that when installed on an airplane surface it minimizes the flow disturbance across pressure sensing element  112  allowing an accurate measurement of the local pressure. Fairing body  104  can be made of any suitable material, for example, stainless steel shim stock.  
         [0022]      FIG. 2  provides a sectional view of fairing assembly  102  cut across belt segment  114  in accordance with an embodiment of the present invention. As shown in  FIG. 2 , belt element  114  is coupled to airplane surface  200  using, for example, tape and the like, such as 3M #92 tape.  
         [0023]     Fairing assembly  102  can be coupled to airplane surface  200  and made to surround belt segment  114  with aero wedges  106  and  108 . In this embodiment, belt segment  114  is disposed within central portion  110  of fairing assembly  102  between aero wedges  106  and  108 . Fairing assembly is mounted to airplane surface  200  using conventional methods, such as tape  204  and the like, for example, 3M Y434 aluminum tape, for ease of installation.  
         [0024]     When properly positioned, a substrate  206  is positioned over belt segment  114 . Substrate  206  can be made of any suitable thickness and material. In one embodiment, substrate  206  can be made of neoprene rubber to a thickness of about 3/32″. In one embodiment, CRES sheet  208  is bonded to substrate  206 . In this embodiment, CRES sheet  208  has a thickness of about 0.005″.  
         [0025]      FIG. 3  provides a sectional view of fairing assembly  102  cut across belt segment  114  and pressure sensing element  112  in accordance with an embodiment of the present invention. In contrast to  FIG. 2 ,  FIG. 3  shows a cavity  302  formed by removal of a portion of substrate  206  under CRES sheet  208 . Cavity  302  provides space for pressure sensing element  112  and other discrete components formed on belt segment  114  while covered by fairing assembly  102 . Sealant  304  is provided to seal cavity  302 .  
         [0026]     In one embodiment, at a prescribed location generally positioned above pressure sensing element  112  is formed a pressure port hole  306 . Pressure port hole  306  allows for the measurement of local pressure by pressure sensing element  112  without the disturbance caused by turbulent airflow. Pressure port hole  306  can be of any suitable diameter, for example, 0.063″ diameter.  
         [0027]     It should be understood, as shown in  FIG. 1 , that belt element  114  can include a plurality of pressure sensing elements  112 . Accordingly, fairing assembly  102  includes a plurality of port holes  306  formed on CRES sheet  308  above each pressure sensing element  112 .  
         [0028]      FIG. 4  is a flowchart describing an assembly method  400  of forming fairing system  100  on the surface of an object.  
         [0029]     In step s 402 , a pressure sensing element is positioned at a measurement location on an object. In one embodiment, a plurality of pressure sensing elements  112  disposed on belt element  114  are secured by tape to the surface of an aircraft.  
         [0030]     In step s 404 , substrate  206  is positioned over belt segment  114  and pressure sensing element  112 . Substrate  206  includes a hole which allows substrate  206  to be placed over belt element  114  and allow pressure sensing element  112  to emerge through substrate  206 .  
         [0031]     In step s 406 , CRES sheet  208  is bonded to substrate  206 . When bonded to substrate  206 , the area over the hole forms cavity  302  in which pressure sensing element  112  resides. In one embodiment, a sealant  304  can be used to seal cavity  302 .  
         [0032]     A pressure port hole  306  is formed in CRES sheet  208  to provide access to otherwise sealed cavity  302  to allow for the measurement of local pressure.  
         [0033]     In step s 408 , fairing body  104  including aero wedges  106  and  108  is positioned over belt element  114 , pressure sensing element  112 , and substrate  206 , such that belt element  114  resides in central portion  110  of fairing assembly  102 . Firing body  104  is secured to airplane surface  200  using tape  204  for ease of installation.  
         [0034]     It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit and scope of the invention. Thus it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.