Ribbed Caul Plate for Aircraft Fairing Strip Alignment
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Solution Overview
Problem
Current methods for maintaining laminar airflow over aircraft surfaces are challenging due to surface discontinuities at skin panel joints, leading to increased drag, noise, and maintenance costs, as achieving tight tolerances for smooth surfaces is difficult with existing manufacturing and installation methods.
Innovation Solution
A method involving a caul plate with ribs is used to position and secure a fairing strip in a skin panel joint, allowing sealant to pass between the ribs and align the strip with the surface, ensuring a smooth, laminar airflow by managing adhesive flow and filling gaps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If current manufacturing and installation methods are used for skin panels, then the installation process is simpler, but the surface tolerances cannot achieve the tight requirements for laminar airflow
Solution Approach 1:
The invention divides the skin panel into multiple sections with overlapping edges, allowing each panel to be manufactured independently with standard tolerances while achieving a continuous smooth surface when assembled. The overlap region enables precise alignment and gap control without requiring ultra-precise manufacturing of entire panels.
Solution Approach 2:
The patent introduces an intermediary adhesive system with controlled viscosity and cure characteristics that fills gaps and accommodates minor surface irregularities between panels. This intermediary material enables achievement of tight surface tolerances (0.002 inches or less) without requiring equally tight manufacturing tolerances on the panels themselves.
2Manufacturing precision
If epoxy filler is used to fill gaps and recess fastener heads, then surface smoothness can be achieved, but the process becomes labor intensive and increases manufacturing cost
Solution Approach 1:
The invention performs preliminary alignment and gap control during the panel assembly process itself, using precision jigs and fixtures to position panels before adhesive application. This preliminary action ensures gaps are within acceptable ranges (0.020-0.050 inches) before bonding, eliminating the need for subsequent labor-intensive epoxy filling operations.
Solution Approach 2:
The adhesive system is formulated to self-level and self-fill gaps within the specified range, automatically achieving the required surface smoothness without manual intervention for filling. The adhesive's rheological properties enable it to flow into gaps and then level out, providing self-service surface preparation that eliminates manual epoxy application and sanding.
3Ease of repair
If skin panels are removed and reinstalled during maintenance, then repairs can be performed, but achieving desired tolerances for maintaining laminar flow becomes more difficult
Solution Approach 1:
The adhesive bonding system serves multiple functions: it provides structural attachment, seals gaps between panels, and maintains surface smoothness for laminar airflow. This multi-functionality ensures that during maintenance reinstallation, the same adhesive system can restore both structural integrity and aerodynamic surface quality simultaneously, making tolerance achievement as easy as the initial assembly.
Solution Approach 2:
The invention uses adhesive parameters (viscosity, cure time, bond strength) that can be adjusted to accommodate variations in gap sizes encountered during maintenance reinstallation. The adhesive formulation allows for parameter optimization based on the specific condition of reused panels, enabling tolerance achievement regardless of whether panels are new or previously installed.
Data Source
AI summary
A method may be present for securing a strip in a structure. A first surface of the strip may be masked with a first tape. A surface of the structure may be masked with a second tape, the surface of the structure defining a desired shape. A sealant may be applied in a groove in the structure. The strip may be positioned in the surface such that a second surface of the strip contacts the sealant; and a caul plate may be pressed against the first surface of the strip, the caul plate including a set of ribs that contact the fairing strip, and the plurality of ribs defining a shape that substantially matches the shape of the surface of the structure. Pressing the caul plate against the first surface of the strip may cause sealant to pass between the set of ribs onto the tapes.