TECHNOLOGY AREAS: Materials/Processes

ACQUISITION PROGRAM: PMA-251, Aircraft Launch and Recovery Equipment Program Office

OBJECTIVE: Develop and implement an innovative system that will inhibit corrosion in the aircraft carrier catapult water brake system.

DESCRIPTION: The design of the water brake for the catapult launch system on aircraft carriers has not substantially changed for almost four decades. The function of the water brake is to stop the catapult launch pistons at the end of their stroke. The water brake system includes an open-ended cylinder that is filled with water via an array of jets at the mouth of the cylinder. A tapered spear attached to the forward end of the launch piston inserts into the cylinder, stopping the launch pistons. The water used in the system is potable water recirculated from an open storage tank located directly below the water brake cylinders. Sea water and other deck effluent contaminate this water through deck openings just above the system. Corrosion of the low alloy steel of the cylinder has resulted in catastrophic failure of the cylinder. To counter the corrosion, a mixture of sodium nitrite and emulsifier had been added to the water brake storage tank to mitigate corrosion. This mixture was reliably used until the emulsifier manufacturer discontinued production, and could no longer be supplied. Due to the recurring concern that catastrophic failure of the water brake cylinder would occur, NAVAIR investigated replacement of the cylinder with a corrosion resistant material. This effort was abandoned due to the unacceptably high cost of the replacement materials. Emphasis was again placed on finding a new corrosion inhibitor or corrosion inhibition system.

A sodium nitrite-based inhibitor added directly to the water brake storage tank has been used in the past with some success. Testing on board aircraft carriers showed a dramatic reduction in corrosion to the components. An emulsifier was added to the sodium nitrite to increase the crevice protection of the inhibitor, but production of this emulsifier ceased. Further attempts to identify a replacement emulsifier were unsuccessful because the products produced copious foam when the water pumps were activated. The water brake produces an extremely turbulent, high pressure, high velocity flow through the jets located in the cylinder opening. Production of any foam negatively affects the performance of the water brake, and cannot be tolerated.

The Navy will consider proposals for a system that actively inhibits corrosion in the water brake components. This system may consist of the following: 1) a product added to the water storage tank, a monitor or sensor for the active level of that product, and, optimally, automatically replenishment of the level of the product; 2) an active system that monitors and inhibits corrosion through an advanced electrochemical technology and control system. Proposals solely for coatings or alternate materials for the water brake cylinder or components will not be considered.

The cost, volume, weight, environmental impact, and health or safety concerns of any product for addition to the water brake tank must be analyzed with emphasis on minimizing the impact of all these concerns.

PHASE I: Determine the feasibility of developing a system that will inhibit the corrosion to the water brake cylinder and corrosion components. Perform laboratory bench tests to support corrosion inhibition performance and foaming potential for any direct additives to the water. Develop an operational concept for the inhibition system. Assess and mitigate any hazardous material issues for personal safety and environmental hazards of the system. Develop and provide defendable estimates for cost, reliability, and maintainability of the inhibition system.

PHASE II: Develop a prototype system. Design and construct a test stand using a water brake cylinder and pump provided by the Naval Air Warfare Center.

PHASE III: Install operational system aboard an aircraft carrier for operational evaluation and qualification testing. Equipment for delivery to carrier fleet and shore sites will be procured. Establish all logistical elements of the system, including Technical Manuals.

PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: The mitigation of corrosion and repair of corrosion damage throughout the world consumes billions of dollars every year. This system could be applicable to any industry that utilizes water for process equipment to inhibit corrosion in those systems.

REFERENCES:
1. The Warfighters Encylopedia, Catapults, Catapults - In Depth. https://wrc.navair-rdte.navy.mil/warfighter_enc/Carriers/catapult.htm

KEYWORDS: Aircraft Carrier; Catapult; Water Brake; Sodium Nitrite; Corrosion; Corrosion Inhibitor

TPOC: (732)323-2716
2nd TPOC: (732)323-1936
3rd TPOC: (732)323-4652

** TOPIC AUTHOR (TPOC) **

DoD Notice:   Between November 13 and December 9, 2007, you may talk directly with the Topic Author(s) to ask technical questions about the topics. Their contact information is listed above. For reasons of competitive fairness, direct communication between proposers and topic authors is not allowed starting December 10, 2007, when DoD begins accepting proposals for this solicitation.

However, proposers may still submit written questions about solicitation topics through the DoD's SBIR/STTR Interactive Topic Information System (SITIS), in which the questioner and respondent remain anonymous and all questions and answers are posted electronically for general viewing until the solicitation closes. All proposers are advised to monitor SITIS (08.1 Q&A) during the solicitation period for questions and answers, and other significant information, relevant to the SBIR 08.1 topic under which they are proposing.

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