Repair Solution for Optically Transparent Canopies and Windscreens

OUSD (R&E) CRITICAL TECHNOLOGY AREA(S): Advanced Materials;Sustainment OBJECTIVE: Develop a repair solution to address scratch and pitting damage to acrylic transparencies or their transparent coatings that is usable within optically critical zones, is executable on-aircraft by intermediate or organizational level maintainers, and decreases aircraft downtime compared with component replacement or depot-level overhaul. DESCRIPTION: Scratches and pits to the acrylic outer ply of canopies and windscreens cause optical distortion as well as structural vulnerability, and these types of damage cause significant readiness degradation. Currently, available repair methods are costly, time-intensive, and extremely limited in the scope of damages that can be addressed, such that damages greater than 10 mils (measurement of unit thickness) in depth are essentially unrepairable. Furthermore, the optical requirements of canopies and windscreens are exacting, and repairs to transparencies must meet the original optical requirements of the components without inducing even minor distortion. The requirements for the baseline material can be seen in the military specification, MIL-PRF-25690 [Ref 2]. Novel repair materials and processes are needed to facilitate optically acceptable repairs larger than the current state of the art. Candidate repair concepts will be compatible with acrylic substrates, executable on aircraft, optically transparent in accordance with baseline aircraft requirements, able to endure in aval aircraft environments, and capable of being inspected for acceptability to existing standards using existing or novel inspection techniques. PHASE I: Define and develop a repair material or concept that meets the requirements listed in the Description. Perform analysis to determine feasibility of the concept. The Phase I effort will include prototype plans to be developed under Phase II. PHASE II: Develop and demonstrate a prototype kit and/or process that meets the requirements listed in the Description. Prototype testing and demonstration will be performed at the canopy shop at Fleet Readiness Center Southwest North Island. PHASE III DUAL USE APPLICATIONS: Perform final testing at organizational and intermediate level repair locations, and transition for use on H-53 and/or F/A-18. The developed technology will also be applicable to commercial aviation and general aviation. REFERENCES: 1. P-P-560C Federal Specification on Plastic Polish. https://quicksearch.dla.mil/qsDocDetails.aspx?ident_number=48516 2. MIL-PRF-25690 Plastic, Sheet and Formed Parts, Modified Acrylic Base, Monolithic, Crack Propagation Resistant. https://quicksearch.dla.mil/qsDocDetails.aspx?ident_number=18093 KEYWORDS: Transparency; Acrylic Outer Ply; Canopy; Window; Windscreen; Repair; Optical Zone; Scratch and Pit Repair