Apparatus for eliminating gaps in an aircraft

An apparatus (30) for eliminating gaps (20) in a door of an airplane has an elastaueric bladder (32) bonding along an edge (24) of a door gap (20). The elastomeric bladder (32) includes a port providing for access to an interior cavity (34). A pneumatic actuator is coupled to the port.

FIELD OF THE INVENTION 
The present invention relates generally to the field of aircraft and more 
particularly to an apparatus for eliminating gaps in an aircraft. 
BACKGROUND OF THE INVENTION 
Modern aircraft have a number of exterior access doors such as landing gear 
doors, avionics access doors and bomb bay doors. Due to the large stresses 
and temperature variations modern aircraft encounter during flight, these 
doors have to accommodate changes in size and shape of the structural 
member forming the doors. Gaps form around the edges of the doors as a 
result of these changes in size. These gaps can cause turbulence that 
increases the drag of the aircraft. The gaps allow dirt and contaminants 
to enter the aircraft, including electromagnetic emissions. The turbulence 
and contaminants reduce the aircraft's mission effectiveness. 
Thus there exists a need for an apparatus to eliminate (reduce) gaps in 
aircraft, so that the gaps do not result in turbulence or allow dirt and 
contaminants into the aircraft. 
SUMMARY OF THE INVENTION 
An apparatus for eliminating gaps in a door of an airplane that overcomes 
these and other problems has an elastomeric bladder bonding along an edge 
of a door gap. The elastomeric bladder includes a port providing for 
access to an interior cavity. A pneumatic actuator is coupled to the port.

DETAILED DESCRIPTION OF THE DRAWINGS 
A modern aircraft 10 is shown in FIG. 1. The aircraft 10 has a number of 
exterior doors along a fuselage 12. An avionics door 14 and equipment 
access door 16 are shown in more detail in FIG. 2. The gaps along the 
edges of these doors in the prior art can be eliminated using the 
apparatus illustrated in FIGS. 3 and 4. In FIG. 3 a door gap 20 exists 
between an edge 22 and an edge 24. A door 26 is seated on a flange of the 
aircraft 28. An apparatus 30 for eliminating the gap 20 is attached 
(bonded) to the edge 24 of the door 26. In another embodiment, the 
apparatus 30 could be attached to the edge 22 of the aircraft 28. The 
apparatus 30 is an elastomeric bladder 32 having an interior cavity 34. A 
port to the interior cavity is attached to a pneumatic mechanism 
(pneumatic pump, actuation mechanism). The pneumatic pump can deflate the 
elastomeric bladder 30 as shown in FIG. 3 or expand the elastomeric 
bladder 30 as shown in FIG. 4. When the elastomeric bladder 32 is 
expanded, the gap 20 is substantially reduced or eliminated. This reduces 
the turbulence due to the gap. In addition, the apparatus 30 reduces the 
amount of dirt and contamination allowed inside the aircraft 28. 
In another embodiment, the elastomeric bladder 32 is covered with a 
conductive material. The conductive material can be a metal coated woven 
cloth. In another embodiment the conductive material can be a conductive 
flexible paint. The conductive material prevents EMI from entering the 
aircraft 28. In yet another embodiment the elastomeric bladder is covered 
with an environmental coating. The environmental coating can be put over 
the conductive material or directly over the elastomeric bladder. The 
environmental coating protects the elastomeric bladder from jet fuel, 
hydraulic oil and a wide variety of other chemical solvents. The 
environmental coating is made from flourosilicones, flouroelastomers, 
silicones, thermoplastic elastomers, urethanes or other viable elastic 
materials. 
The elastomeric bladder 32 can be attached to a variety of surfaces. In one 
embodiment the elastomeric bladder is attached to the edge of a reinforced 
elastomer skin 26, having reinforcing rods 36. Other common materials that 
the elastomeric bladder 32 is attached to include metal and composites. 
FIG. 5 is another embodiment of an apparatus 50 for closing a gap in an 
aircraft. The apparatus 50 is a modified reinforced elastomer panel, 
having a pair of rod blocks 52, 54 with an elastomer skin 56 between them. 
A plurality of reinforcing rods 58 are attached to the rod block 52 and 
slide freely through elastomer skin 56 and the rod block 54. The rod 
blocks 52, 54 have attachment provisions 60. A plurality of shape memory 
alloy ribs 62 are interleaved with the plurality of reinforcing rods 58 
along an angled section 64 of the rod blocks 52, 54. The shape memory 
alloy (SMA) ribs 62 are connected to an electrical current source. When an 
electrical current is applied to the SMA ribs 62 they change from a first 
shape to a second shape. In one embodiment, the SMA ribs 62 bow out toward 
the edge 66 of the elastomer 56 to push the elastomer edge 66 to the 
position 68 shown in dashed lines. This closes the gap next to an 
elastomer panel. 
FIGS. 6a and 6b show another embodiment of an apparatus 80 for eliminating 
a gap in an aircraft. An elastomeric sock 82 has an internal cavity 84. A 
plurality of shape memory alloy (SMA) ribs 86 extend along the length of 
the elastomeric sock 82. When the SMA ribs are in the expanded position 
(FIG. 6b) the elastomeric sock is pushed outward to close a gap. A pair of 
electrical leads 88 are used to provide electrical current to the SMA ribs 
86 and to cause the electrical ribs to change from a retracted position 
(FIG. 6a) to the expanded position. An edge 90 of the elastomeric sock can 
be bonded to edge of a door gap. The apparatus 80 can be attached where 
ever a gap exists on an aircraft. 
FIGS. 7a and 7b show part of another embodiment of an apparatus 100 for 
closing a door gap on an aircraft. The apparatus 100 of FIGS. 7a and 7b 
would be encased in an elastomeric bladder. The apparatus 100 has a shape 
memory alloy spring 102, 104 that is attached to a base 106 and connected 
to a rigid member 108. The SMA spring 102, 104 slides along a slat 110, 
112 when the SMA spring changes from a retracted position (FIG. 7a) to an 
expanded position (FIG. 7b). When the apparatus is in the expanded 
position, the rigid member 108 pushes an elastomeric bladder outward to 
close a door gap. The elastomer covering the base 106 is bonded (attached) 
to an edge of a gap. 
Thus there has been described an apparatus for closing (eliminating) a gap 
in an aircraft. The apparatus reduces the turbulence due to gaps, reduces 
the amount of dirt and contaminates that enter the aircraft and reduces 
the EMI that can enter the aircraft. While the invention has been 
described in conjunction with specific embodiments thereof, it is evident 
that many alterations, modifications, and variations will be apparent to 
those skilled in the art in light of the foregoing description. 
Accordingly, it is intended to embrace all such alterations, 
modifications, and variations in the appended claims.