Abstract:
A drainmast assembly ( 10 ) for ejecting gray water from the onboard potable water system of an aircraft. The assembly ( 10 ) includes an interface ( 14 ) mounted on the fuselage of the aircraft and a drainmast ( 16 ) including a fairing ( 90 ) aligned with and attached to the interface ( 14 ). The interface ( 14 ) includes a pipe ( 46 ) having an outlet nipple ( 48 ) which is pivotally connected to an inlet portion ( 146 ) of the draintube ( 94 ). In this manner, the draintube ( 94 ) can rotate relative to the interface ( 14 ) should the fairing ( 90 ) be unintentionally hit by a baggage vehicle and shoved out of alignment with the interface ( 14 ).

Description:
RELATED APPLICATIONS  
       [0001]     This application claims priority under 35 U.S.C. § 119 (e) to U.S. Provisional Patent Application No. 60/539,415 filed on Jan. 26,2004. The entire disclosure of this provisional application is hereby incorporated by reference. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention relates generally to an aircraft drainmast assembly and, more particularly, to a drainmast assembly for ejecting potable waste water (i.e., gray water) from an onboard potable water system of an aircraft.  
       BACKGROUND OF THE INVENTION  
       [0003]     A drainmast assembly is used to eject gray water from an aircraft. A typical drainmast includes a fairing attached to the fuselage of the aircraft and a draintube extending through the fairing. The draintube usually includes an inner pipe having an inlet portion which interfaces with the onboard potable water system and an outlet portion from which this water is ejected. To prevent water from freezing as it passes through the pipe, and/or just after it is ejected therefrom, a draintube can incorporate one or more heaters, temperature-sensing instrumentation to coordinate normal and emergency control of the heater(s), and electrical lines leading to/from the heater(s) and the instrumentation.  
       SUMMARY OF THE INVENTION  
       [0004]     The present invention provides a drainmast assembly which protects the aircraft-drainmast interface should the drainmast be unintentionally struck (e.g., by a baggage cart) when the aircraft is grounded. More particularly, the present invention provides a drainmast assembly comprising an interface mounted to the fuselage and a drainmast having a fairing aligned with the interface and attached thereto. The interface includes a pipe having an inlet portion connected to the onboard potable water system and an outlet portion pivotally connected to an inlet portion of the draintube. In this manner, the draintube can rotate about the interface pipe upon movement of the fairing out of alignment with the interface.  
         [0005]     The present invention also provides a draintube design wherein heat output is properly and predictably directed to inner/outer outlet areas. More particularly, the present invention provides an inner outlet heater, an outer outlet heater, and a heater-separating sleeve positioned therebetween. The heater-separating sleeve acts as a thermal barrier between the outlet heaters, and also preferably pushes the inner outlet heater radially inward (towards the inner pipe) and pushes the outer outlet heater radially outward (towards the socket). Preferably, the heater-separating sleeve has a high coefficient of thermal expansion whereby it expands at high heater temperatures and/or is surrounded by an outlet socket which places it in a state of compression.  
         [0006]     The present invention additionally provides an outlet heating arrangement which allows the endcap area and the inner pipe area to be heated at different power levels. More particularly, the present invention provides a drain tube wherein an outer outlet heater outputs at least two times more heat than the inner outlet heater. In this manner, the inner pipe area can be moderately heated to prevent freezing of water therein and the endcap area can be aggressively heated to prevent ice from plugging the drainmast discharge.  
         [0007]     The present invention also provides a heater layout which can improve draintube reliability and life expectancy. More particularly, the present invention provides a draintube wherein a central heater, an inner outlet heater, and/or an outer outlet heater are formed from a single heater strip. The heating strip comprises a flexible film substrate and heating elements printed or etched thereon, preferably in a single circuit. The film substrate has at least one tail section that is wrapped around the outlet portion of the pipe to form an outlet heater and a ribbon section that is wrapped (e.g., spirally coiled) around the central portion of the pipe to form the central heater.  
         [0008]     The present invention additionally provides a heater construction that allows a strip heater to be properly positioned on the pipe of the draintube assembly. More particularly, the present invention provides a draintube wherein the strip heater includes a ribbon section that is spirally wrapped around. a portion of the pipe and is secured thereto by a hot melt adhesive. During assembly of the draintube, the hot melt adhesive is untacky at room temperature whereby the ribbon section can be shifted and repositioned to obtain a desired positioning. Once the desired positioning has been achieved, a heat-applying step (e.g., an oven cure) can be performed to bond the ribbon section permanently in place relative to the inner pipe of the draintube.  
         [0009]     The present invention also provides a draintube wherein temperature-sensing instrumentation is located close the drainmast discharge to thereby more closely track outside environmental conditions. More particularly, the present invention provides temperature-sensing instrumentation sealed and potted within a radially inner wall of an outlet socket. The outlet socket can have a clamshell construction comprising two halves which are mechanically fastened together.  
         [0010]     These and other features of the invention are fully described and particularly pointed out in the claims. The following descriptive annexed drawings set forth in detail a certain illustrative embodiment of the invention, this embodiment being indicative of but one of the various ways in which the principles of the invention may be employed. 
     
    
     DRAWINGS  
       [0011]      FIG. 1  is a schematic view of a drainmast assembly according to the present invention installed on an aircraft.  
         [0012]      FIG. 2  is an exploded side view of the components of the drainmast assembly, these components including an interface and a drainmast.  
         [0013]      FIGS. 3A-3C  are top, side, and bottom views, respectively, of the interface.  
         [0014]      FIGS. 3D and 3E  are sectional views of towers of the interface as seen along line  3 D- 3 D and line  3 E- 3 E, respectively, in  FIG. 3A .  
         [0015]      FIG. 4A  is a plan view of a heater for the interface, the heater being shown isolated from the rest of the interface and in a flat pre-assembly condition.  
         [0016]      FIG. 4B  is a side sectional view of the interface heater.  
         [0017]      FIG. 4C  is a close-up view of a portion of the heater.  
         [0018]      FIGS. 5A-5D  are top, fore, side, and aft views, respectively, of the drainmast.  
         [0019]      FIG. 5E  is a sectional view as seen along line  5 E- 5 E in  FIG. 5D .  
         [0020]      FIG. 5F  is a sectional view as seen along line  5 F- 5 F in  FIG. 5E .  
         [0021]      FIG. 6  is a side view, partly in section, of the interface and the drainmast installed on a fuselage mounting surface of an aircraft.  
         [0022]      FIGS. 7A-7D  are top, fore, side, and aft views, respectively, of the draintube isolated from the fairing.  
         [0023]      FIG. 7E  is a sectional view as seen along line  7 E- 7 E in  FIG. 7A .  
         [0024]      FIG. 7F and 7G  are sectional views as seen along line  7 F- 7 F and line  7 G- 7 G, respectively, in  FIG. 7C .  
         [0025]      FIG. 7H  is a sectional view as seen along line  7 H- 7 H in  FIG. 7D .  
         [0026]      FIG. 8A  is a plan view of an inlet heater for the draintube, the inlet heater being shown isolated from the rest of the interface and in a flat pre-assembly condition.  
         [0027]      FIG. 8B  is a side sectional view of the draintube&#39;s inlet heater.  
         [0028]      FIG. 8C  is a close-up view of a portion of the draintube&#39;s inlet heater.  
         [0029]      FIG. 9A  is a plan view of a strip used to form a central heater and outlet heaters for the draintube, the strip being shown in a flat, unassembled condition.  
         [0030]      FIG. 9B  is a side sectional view of an elongated ribbon section of the heater strip.  
         [0031]      FIG. 9C  is a side sectional view of a tail section of the heater strip.  
         [0032]      FIG. 9D  is a side sectional view of another tail section of the heater strip.  
         [0033]      FIG. 9E  is a close-up view of a portion of the heater strip.  
         [0034]      FIG. 9F  is a plan view of the ribbon section of the heater strip wrapped around a central portion of an inner pipe of the draintube.  
         [0035]      FIGS. 10A and 10B  are side and front views, respectively, of a first half of an outlet socket for the draintube.  
         [0036]      FIG. 10C  is a sectional view as seen along line  10 C- 10 C in  FIG. 10A .  
         [0037]      FIGS. 10D and 10E  are auxiliaryviews of the first socket half as seen along lines  10 D- 10 D and  10 E- 10 E, respectively, in  FIG. 10B .  
         [0038]      FIGS. 10F, 10G , and  10 H are side, top and front views, respectively, of the second half of the outlet socket. 
     
    
     DETAILED DESCRIPTION  
       [0039]     Referring now to the drawings in detail, and initially to  FIG. 1 , a drainmast assembly  10  according to the present invention is shown installed on an aircraft  12 . The drainmast assembly  10  comprises an interface  14  and a drainmast  16 . The interface  14  is permanently fixed to a mounting surface  18  of the aircraft&#39;s fuselage and is connected to an onboard plumbing outlet  20  and an onboard electrical source/control  22 . The drainmast  16  is mounted to the interface  14  and thereby interfaced with the aircraft&#39;s plumbing outlet  20  and electrical source/control  22 .  
         [0040]     Referring now to  FIG. 2 , the drainmast assembly  10  is shown in more detail. In addition to the interface  14  and the drainmast  16 , the assembly  10  can also include an O-ring  24  and a gasket  26 . When the drainmast assembly  10  is installed on the aircraft  12 , the O-ring  24  is seated within a groove in a plumbing portion of the interface  14  (namely a groove  58  in a nipple  48 , introduced below) and the gasket  26  is sandwiched between the aircraft fuselage mounting surface  18  and a flange of the drainmast  16  (namely a fairing flange  98 , introduced below). The assembly  10  can further comprise fasteners  28  that are used to secure the drainmast  16  to the interface  14  and to the fuselage  18 .  
         [0041]     Referring now to  FIGS. 3A-3C , the interface  14  is shown isolated from the rest of the drainmast assembly  10 . The interface  14  comprises a mounting plate  30 , a plumbing tower  32 , and an electrical tower  34 . The mounting plate  30  includes fore and aft openings  36 , and also four corner openings  38  covered by sealed nutplates  40 . The plumbing tower  32  and the electrical tower  34  are secured to, and extend through, the mounting plate  30 .  
         [0042]     As is best seen by referring additionally to  FIG. 3D , the plumbing tower  32  comprises an interface pipe  46 , a nipple  48 , and a housing  50 . The pipe  46  has a fitting  52  on its upper inlet portion for connection to the aircraft plumbing outlet  20  and can be surrounded by a heater  54  and an insulating sleeve  56 . The nipple  48  surrounds a bottom outlet portion of the pipe  46  which extends through and below the mounting plate  30  and includes a groove  58  for the O-ring  24 . The housing  50  surrounds the upper portion of the pipe  46  and includes a grommet  60  through which electrical wires  62  and  64  enter/exit the tower  32 . (See  FIGS. 3A and 3B .) A mounting flange  66  surrounds the housing  50  and the nipple  48 , and it secures the tower  32  to the mounting plate  30  via fasteners  68 .  
         [0043]     As is best seen by referring additionally to  FIG. 3E , the electrical tower  34  comprises a top electrical connector  70  for connection to the onboard electrical source/control  22 , a bottom electrical connector  72  for connection to the drainmast  16 , and an adapter  74  therebetween. A housing  76  can surround these components and can include a clamp  78  for connection of the heater wire  64  from the plumbing tower  32 . (See  FIGS. 3A and 3B .)  
         [0044]     As is best seen by referring additionally to  FIG. 4A , the interface heater  54  comprises a thin (e.g., 0.10 mm or less) substrate film  84  having heating elements  86  printed or etched thereon. In the illustrated embodiment, the substrate film  84  has a roughly rectangular shape to surround the cylindrical interface pipe  46 . An adhesive coating  88  (e.g., a pressure-sensitive-adhesive) can be applied to the printed/etched side of the substrate film  84  to adhesively secure the heater  54  to the interface pipe  46 . (See  FIG. 4B .) The heating elements  86  are oriented so that their lead sections are positioned for convenient connection to the wires  64  extending through the grommet  60  in the housing  50 . (See  FIG. 4C .) Referring now to  FIGS. 5A-5D , the drainmast  16  is shown isolated from the rest of the assembly  10 . The drainmast  16  comprises a fairing  90 , an endcap  92 , a draintube  94 , and an electrical harness  96 . The endcap  92  is attached to the discharge end of the fairing  90 , the draintube  94  is positioned within the fairing  90 , and the electrical harness is also positioned within the fairing  90 . The fairing  90  comprises a mounting flange  98  and a mast  100  sweeping therefrom to the endcap  92 . The mounting flange  98  further includes four openings  104  which are alignable with the four corner openings  38  on the mounting plate  30 .  
         [0045]     The draintube  94  extends through the flange opening  102 , through the mast chamber, and into the cylindrical passageway of the endcap  92 . (See also  FIGS. 5E and 5F .) More specifically, the draintube  94  has an inlet portion  106 , which is positioned flush with (or just below) the upper surface of the fairing mounting flange  98 , and an outlet portion  108  which extends into the cylindrical passageway in the endcap  92 . The inlet portion  106  can be secured to the fairing flange  98  via an attachment plate  110  (and associated fasteners) and the outlet portion  108  can be secured to the endcap  92  via fasteners  112 .  
         [0046]     The electrical harness  96  comprises a connector  114  for electrical connection with the bottom connector  72  of the interface  14 . The electrical connector  114  is moveably positioned within the mast chamber so that it can be lifted through the central opening  102  in the fairing flange  98 . As is explained in more detail below, the draintube  94  includes electrical heaters and the associated wires are bundled in a cable  116  which extends between the draintube  94  and the electrical harness  96 . The harness  96  can be loosely secured to the fairing  90  by an attachment tab  118  secured to the flange  98  and a landyard  120  loosely extending between the tab  118  and the connector  114 .  
         [0047]     Referring now to  FIG. 6 , the interface  14  and the drainmast  16  are shown installed on an aircraft  12 . In the installation process, the mounting plate  30  of the interface  14  is positioned above the fuselage mounting surface  18  about an appropriate opening. The interface  14  is permanently secured to the fuselage  18  by fasteners  122  which extend through the fore/aft holes  36  on the mounting plate  30 . Although not visible in the illustrated view, the fuselage mounting surface  18  includes holes which align with the corner holes  38  of the interface mounting plate  30 .  
         [0048]     After the interface  14  is permanently mounted to the aircraft  12 , the drainmast  16  is held adjacent the mounted interface  14  to begin the drainmast mounting steps. The electrical connector  114  of the harness  96  is lifted above the fairing  90  and mated with the bottom electrical connector  72  of the interface tower  34 . The O-ring  24  is placed within the groove  58  of the nipple  48  and the gasket  26  is positioned for sandwiching between the fuselage mounting surface  18  and the fairing flange  98 . The drainmast  16  is then aligned with the interface  14  so that the nipple  48  is aligned with the draintube inlet  106  and so that the fairing flange openings  104  are aligned with the corner openings  38  on the interface plate  30  (and the corresponding four openings in the fuselage  18 ). The drainmast  16  is then slid up onto the nipple  48  and secured to the interface/fuselage with the four fasteners  28  (not visible in  FIG. 6 , but shown in  FIG. 2 ) which extend upwardly through the fairing flange openings  104 , the openings in the fuselage, the interface openings  38  and into the sealed nutplates  40 . Thus, the illustrated drainmast  16  can be completely installed to the aircraft  12  from outside of the fuselage.  
         [0049]     The drainmast-interface arrangement (e.g., the slip-fit nipple connection and the slack electrical cable  100 ) of the assembly  10  helps to protect the interface  14  should the drainmast  16  be unintentionally struck (e.g., by a baggage cart) when the aircraft  12  is grounded. Specifically, should the fairing  90  be forced out of alignment with the interface  14 , the draintube  94  can pivot about the interface nipple  48  and the electrical harness  96  can accommodate this movement without damaging the interface  14 . Moreover, especially if the drainmast-interface fasteners  28  are fracturable fasteners, the drainmast  16  itself may also be salvageable for further use after the collision.  
         [0050]     Referring now to  FIGS. 7A-7H , the draintube  94  is shown isolated from the rest of the drainmast  16 . The draintube  94  comprises an inner pipe  130 , an inlet heater  132 , a central heater  134 , and an insulating sleeve  136 . The pipe  130  extends from the inlet to the outlet of the draintube  94  and forms a passageway for the gray water therethrough. The inlet heater  132  surrounds the inlet region of the pipe  130 , the central heater  134  surrounds the central region of the pipe  130 , and the insulating sleeve  136  surrounds both the inlet heater  132  and the central heater  134 .  
         [0051]     The draintube  94  further comprises an inner outlet heater  138 , a heater-separating sleeve  140 , an outer outlet heater  142 , and an outlet socket  144 , which sequentially surround an outlet portion of the pipe  130 . (See particularly  FIG. 7H .) This dual-heater and sleeve-socket arrangement allows heat to be properly directed to inner/outer outlet regions of the drainmast  16 . Specifically, the heater-separating sleeve  140  acts as a thermal barrier between the outlet heaters  138  and  142 . It also preferably acts as a “spring” that is placed in compression by the socket  144  whereby the compressive forces push the inner outlet heater  138  radially inward towards the pipe  130  and push the outer outlet heater  142  radially outward towards the socket  144 . Moreover, if the sleeve  140  is silicone as preferred, or any other material having a high coefficient of thermal expansion (i.e., greater than 0.01 mm/° C.), it will expand as heater temperature increase thereby further promoting desired heater contact.  
         [0052]     The two distinct outlet heaters  138  and  142  allows the endcap  92  and the inner pipe  130  to be heated at different power levels. For example, the outer outlet heater  142  can have a heat output that is at least about two times the heat output of the inner outlet heater  138 . With the illustrated drainmast  16 , tunnel testing has shown that fifteen watts on the inner heater  138  and forty watts on the outer heater  142  will maintain the endcap  92  and the draintube  94  at desired temperature conditions.  
         [0053]     The heat output differential between the outlet heaters  138  and  142  is advantageous because of the different heating requirements inherent at the outlet of a drainmast design. The inner pipe  130  must be only moderately heated to prevent freezing of relatively warm gray water passing therethrough, while the endcap  92  must be aggressively heated because of the high cooling load placed on it due to forced air convention during flight. If the outer endcap area is not adequately heated, just-ejected gray water can freeze and form a discharge-blocking ice plug over the endcap  92 . In the past, the solution was “overheating”inner outlet areas (which can dramatically decrease draintube life expectancy) to avoid ever “underheating” the outer outlet areas.  
         [0054]     As is best seen by referring additionally to  FIG. 8A , the inlet heater  132  is preferably comprised of a thin substrate film  150  (e.g., 0.10 mm or less thick) having foil heating elements  152  printed or etched thereon. The flexible substrate film  150  is shaped to conform tightly to the contours of the pipe  130  in the inlet portion  106  and the heating elements  152  are dimensioned and/or arranged to provide the desired heating pattern. An adhesive coating  154  (e.g., a pressure-sensitive-adhesive) can be applied to the printed/etched side of the substrate film  150  so that the heater  132  can be adhesively attached to the inlet portion of the pipe  130 . (See  FIG. 8B .) The leads to the heating elements  152  are positioned at a lower part of the substrate film  150  for convenient interconnection with the cable  116  extending to the electrical connector  114 . (See  FIG. 8C .)  
         [0055]     As is best seen by referring additionally to  FIG. 9A , the central heater  134 , the inner outlet heater  138 , and the outer outlet heater  142  are preferably formed from a single strip  160 . The strip  160  comprises a thin substrate film  162  (e.g., 0.10 mm or less thick) having the foil heating elements  164  printed or etched thereon. The substrate film  162  has an elongated ribbon section  166  (corresponding to the central heater  134 ), a tail section  168  (corresponding to the inner outlet heater  138 ) directly joined to the ribbon section  166 , and another tail section  170  (corresponding to the outer outlet heater  142 ) joined to the tail section  170  by a connecting tab  172 . The heating elements  164  on the different sections  166 ,  168 , and  170  can positioned and/or patterned to heat the corresponding different regions of the draintube  94  at different power levels, such as was discussed above in relation to the inner and outer outlet heaters  138  and  142 . In the illustrated embodiment, for example, the heating elements  164  are much “denser” on the tail section  170  (Le., the outer outlet heater  142 ) than on the tail section  168  (i.e., the inner outlet heater  138 ).  
         [0056]     The heater element layout on the strip  160  is preferably accomplished with one heater circuit whereby no separate leads are required for connection to the different heating areas. For example, in the illustrated embodiment, the two leads for the entire strip  160  can be positioned at the “non-tail” end of the ribbon section  166  for convenient interconnection with the cable  116  extending to the electrical connector  114 . (See  FIG. 9E .)  
         [0057]     An adhesive coating  176  can be applied to the etched/printed side of the ribbon section  166 , an adhesive coating  178  can be applied to the etched/printed side of the tail section  168 , and an adhesive coating  180  can be applied to the. nonetched/nonprinted side of the tail section  170 . (See  FIGS. 9B-9D .) Preferably, the adhesive coating  176  for the ribbon section  166  comprises a heat-melt adhesive which is not tacky at room temperature. The adhesive coating  178  for the tail section  168  and/or the adhesive coating  180  for the tail section  170  can be pressure-sensitive adhesive coating(s).  
         [0058]     To assemble the heaters  132 , 134 ,  138 , and  142  on the inner pipe  130 , the inlet heater  132  can be wrapped around the inlet portion and the tail section  168  of the heater strip  160  can be wrapped around the outlet portion of the pipe  130 . If the adhesive coatings  154  and  178  comprise pressure-sensitive adhesive coatings, as preferred, heater-to-pipe attachment can be accomplished at room temperature.  
         [0059]     The ribbon section  166  of the heater strip  160  is spirally wrapped around the central portion of the pipe  130 . (See  FIG. 9F .) If the adhesive coating  176  comprises a hot-melt-adhesive which is not tacky at room temperature, the ribbon section  166  will not “stick” to the pipe  130 . This very advantageously allows post-wrapping shifting and repositioning of the coiled ribbon section  166 , and even the option of re-doing a poorly executed initial coiling, so that the desired spiral pattern can be obtained. (With a pressure-sensitive-adhesive, for example, such maneuvering would be difficult.) Once the desired spiral pattern of the ribbon section  166  has been reached, it can be temporarily held in place by a piece of tape (not shown) secured to its upper end. A later heat-application step (e.g., an oven cure) can be performed to permanently secure the ribbon section  166  in this position.  
         [0060]     As was indicated above, the heater-separating sleeve  140  is positioned between the inner outlet heater  138  and the outer outlet heater  142 . Preferably, the sleeve  140  comprises a silicone heat-shrink sleeve which is placed over the two layers of the previously attached tail section  168  (i.e., the inner outlet heater  138 ) and heat-shrunk thereonto. Thereafter, the tail section  170  of the heater strip  160  (i.e., the outer outlet heater  142 ) is wrapped around the sleeve  140 . If the tail&#39;s adhesive coating  180  is a pressure-sensitive adhesive coating, as preferred, heater-to-sleeve attachment can be accomplished at room temperature.  
         [0061]     After attachment of the outer outlet heater  142 , the outlet socket  144  is placed thereover. As is best seen by referring to  FIGS. 10A-10H , the outlet socket  144  preferably has a clam-shell construction with two halves  190  and  192 . The first half  190  comprises a semi-cylindrical body  194  and the second half  192  comprises a semi-cylindrical body  196 , each body  194 / 196  having a circumferential groove  198  formed on its radially outer wall. The bodies  194  and  196  also each include tangential openings  200  and bottom axial-extending openings  202 .  
         [0062]     The first socket half  190  additionally includes pockets  204  and  206  accessible from its radially inner wall. Temperature sensing equipment (e.g., a thermostat  208  and as sensor  210 ) are potted and sealed within the pockets  204  and  206 . Lead wires  212  from the thermostat  208  and sensor  210  extend through channels in the pockets  204  and  206  and beyond the top edge of the bodies  194  and  196 . It may be noted that temperature-sensing instrumentation  208 / 210  can be sealed within the socket  144  prior to its incorporation into the draintube  94 . This allows pre-incorporation testing of the instrumentation and consistency/repeatability between similar drainmast units. Also, as best seen by referring briefly back to  FIG. 5F , when the socket  144  is incorporated into the draintube  94 , the instrumentation  208 / 210  is advantageously located near the most ice-plugging-susceptible area on the drainmast  16  (i.e., the endcap area). This location provides very meaningful temperature readings to better track environmental conditions just outside the drainmast  16 .  
         [0063]     When the socket halves  190  and  192  are placed over the outer outlet heater  142 , the semi-circular grooves  198  are aligned with each other to form a circumferential groove about the socket  144 . The tangential openings  200  are aligned and fasteners  214  are inserted to secure the halves  190  and  192  together. (The fasteners  214  are shown in  FIGS. 7A and 7C .) The insulating sleeve  136  can then be molded onto the inlet heater  132  and the central heater  134  to complete the assembly of the draintube  94 .  
         [0064]     Priming, sizing, and/or smoothing steps may be necessary before/after certain of the above-discussed assembly steps to insure secure, wrinkle-free, and otherwise appropriate compilation of the draintube components. For example, primer may be applied to the inner pipe  130  prior to adhesively attaching the heaters  132  and  38 , and primer may be applied to the heater  142  prior to adhesively attaching it to the sleeve  140 . Also, clamps may be necessary to maintain the sleeve  140  and/or the outer outlet heater  142  in a cylindrical shape during curing/cooling steps. Further, components might need to be temporarily wrapped with tapes or films (e.g., Mylar tape and/or Kapton tape, which are registered trademarks of E.I.DuPont DeNemours of Delaware) during clamping and curing steps.  
         [0065]     Referring now back to the fifth and seventh series of drawings, a teardrop-shaped tab  220  is welded or otherwise attached to the interfacing end of the pipe  130  and is attached, via a fastener  222 , to the attachment plate  110 . (See  FIGS. 5A and 7E .) The outlet socket  144  extends beyond the fairing&#39;s discharge end and the inner pipe  130  extends beyond the outlet socket  144 . (See  FIG. 5E .) The endcap  92  is positioned around the inner pipe  130  and the outlet socket  144  is secured thereto by the fasteners  112  which extend through openings aligned with the axial openings  202  in the socket  144 . ( FIGS. 5D and 5E .) A plate  226  may be positioned between the endcap  92  and the socket&#39;s axial end, an O-ring  228  may be positioned within the groove  198 , a moisture sealant  230  may be positioned between the side walls of the endcap  92  and the socket  144 , and/or grease may be appropriately applied between components. (See  FIG. 5E .)  
         [0066]     One may now appreciate that the present invention provides a drainmast assembly  10 , an interface  14 , a drainmast  16 , and/or a draintube  94  which provides many advantages over earlier designs. Although the invention has been shown and described with respect to a certain preferred embodiment, it is obvious that equivalent and obvious alterations and modifications will occur to others skilled in the art upon the reading and understanding of this specification. The present invention includes all such alterations and modifications and is limited only by the scope of the following claims.