Self-Healing Fuel Tank Bladders for Reduced Aircraft Maintainability

TECH FOCUS AREAS: General Warfighting Requirements (GWR) TECHNOLOGY AREAS: Materials; Air Platform OBJECTIVE: To develop, produce, and transition a flexible, lightweight self-healing fuel tank bladder for military aircraft that can survive in-service fuel leaks. Fuel leaks from pinholes and seams in aircraft fuel cell bladders are a heavy maintenance burden, particularly for refueling aircraft such as the KC-135. Fuel leaks are a key factor in non-mission readiness for these aircraft. The self-healing function should be integral to the bladders and have weight increase of not greater than 3% (objective) or 10% (threshold). While self-healing materials previously have been developed for saltwater environments, currently there are none for aircraft fuels. DESCRIPTION: To reduce the maintenance burden and expand the usable life of fuel cells, self-healing bladders are needed to detect and heal minor pinhole leaks and seeps from seams and/or around fittings. Self-healing bladders will reduce costs by reducing the amount of human interaction, system downtime, and the need for part replacement. In turn, the self-healing function will reduce maintainability and extend the mission. Currently there are no commercially available self-healing bladders. Requirements for the self-healing function include: (1) should be integral to the bladders and not reduce flexibility; (2) have weight gain of not greater than 3% (objective) or 10% (threshold); (3) should not alter the capability to contain fuel; and (4) should not hinder the installation nor the removal of the bladders. The unique shapes and complexity of modern fuel cell bladders should be considered in any proposal, which should address all the requirements of MIL-DTL-6396, Type II. The self-healing capabilities of the bladders should be activated within 2 minutes of fuel leak initiation and be able to permanently seal (objective) or seal for at least 3 years (threshold). Concepts should be able to be readily integrated into the current manufacturing processes of aircraft fuel cell bladders. PHASE I: This topic is intended for technology proven ready to move directly into a Phase II. Therefore, a Phase I award is not required. The offeror is required to provide detail and documentation in the Direct to Phase II proposal which demonstrates accomplishment of a Phase I-like effort, including a feasibility study. This includes determining, insofar as possible, the scientific and technical merit and feasibility of ideas appearing to have commercial potential. PHASE II: Eligibility for D2P2 is predicated on the offeror having performed a Phase I-like effort predominantly separate from the SBIR Programs. Under the phase II effort, the offeror shall sufficiently develop the technical approach, product, or process in order to conduct a small number of advanced manufacturing and/or sustainment relevant demonstrations. Identification of manufacturing/production issues and or business model modifications required to further improve product or process relevance to improved sustainment costs, availability, or safety, should be documented. Air Force sustainment stakeholder engagement is paramount to successful validation of the technical approach. These Phase II awards are intended to provide a path to commercialization, not the final step for the proposed solution. PHASE III DUAL USE APPLICATIONS: The contractor will pursue commercialization of the various technologies developed in Phase II for transitioning expanded mission capability to a broad range of potential government and civilian users and alternate mission applications. Direct access with end users and government customers will be provided with opportunities to receive Phase III awards for providing the government additional research & development, or direct procurement of products and services developed in coordination with the program. REFERENCES: 1. Davies, J, Shipman, J, Davidson, W. Self Sealing Fuel Tank Construction , US Patent 2,446,815. 2. Monk, R.; Ohnstad, T.; Henry, J.; Projectile Barrier and Method , US Patent 7,169,452 ; 3. MIL-DTL-6396, Tanks, Fuel, Oil, Cooling Fluids, Internal, Removable Non-Self-Sealing KEYWORDS: Fuel Bladders; Self-healing