Advanced Fluid Line Connectors/Fittings

Navy SBIR 23.2 - Topic N232-091
NAVAIR - Naval Air Systems Command
Pre-release 4/19/23   Opens to accept proposals 5/17/23   Closes 6/14/23 12:00pm ET

N232-091 TITLE: Advanced Fluid Line Connectors/Fittings


The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), 22 CFR Parts 120-130, which controls the export and import of defense-related material and services, including export of sensitive technical data, or the Export Administration Regulation (EAR), 15 CFR Parts 730-774, which controls dual use items. Offerors must disclose any proposed use of foreign nationals (FNs), their country(ies) of origin, the type of visa or work permit possessed, and the statement of work (SOW) tasks intended for accomplishment by the FN(s) in accordance with the Announcement. Offerors are advised foreign nationals proposed to perform on this topic may be restricted due to the technical data under US Export Control Laws.

OBJECTIVE: Develop a novel fluid line connector that reduces the likelihood of fluid leaks that can result in platform downtime and affect reliability. Technology developed under this SBIR topic will ideally be used as a new standard for fluid connections and be more reliable and maintainable than our current industry standards.

DESCRIPTION: The Navy requires a novel fluid line connection that greatly improves the reliability and ease of installation for high-pressure fluid line interfaces for aerospace applications. High-pressure fluid leaks have been found to be a major maintenance driver on several programs, negatively impacting aircraft maintenance costs, readiness, and safety. New connector technologies and designs are needed to reduce the likelihood of fluid leaks and subsequent aircraft downtime. In particular, positive indication of correct installation has been a challenge in blind installations, which has led to leaks discovered during ground turns. Both in-flight and on-ground fluid leaks can lead to negative safety events by way of loss of lube, fire, or loss of flight controls. Fluid connections are regularly touched during maintenance and require a robust design. The research and design performed under this SBIR topic will need to be unlike current fluid connection technologies used in the industry in order to show significant improvements in reliability. The technology will also need to be applicable and scalable to different applications to improve reliability throughout Navy engine platforms. Existing connections include B-nuts, Rosan fittings, and two-piece elastomer seals with backing rings, which are susceptible to poor installation or disconnection during operation. Fittings are also susceptible to high-cycle fatigue that can lead to failure, as such, the design should consider installation stresses coupled with the aerospace environment of high temperature and vibration. Connections between fluid lines, which can range in size from 0.25 in. (.63 cm) to 5 inches (centimeters) in diameter and pressure from 50�5000 psi depending on the application, should be the primary focus of this topic. Innovative solutions are being sought to fully seal pressurized aerospace fluids at a connection point without adverse effects to the fluid flow. Aircraft fluids include fuel, oil, and hydraulic fluid. The installation process and procedures should be considered throughout the design process, in addition to the manufacturing process. Integration and adaptability to current fluid tube designs will aid in future transition efforts.

PHASE I: Demonstrate, through modeling or subscale testing, the ability to fully seal pressurized aerospace fluids at a connection point without adverse effects to the fluid flow. The design can focus on fuel, oil, or hydraulics but would preferably be applicable to all three. Installation procedures should be proposed and explanation of the manufacturing process should be provided for both the seals and the fluid tube components, as well as the adaptability to current fluid tube designs. The Phase I effort will include prototype plans to be developed under Phase II.

PHASE II: Design, develop, and demonstrate functioning prototype(s) based on Phase I design concepts. Validation testing should be performed under relevant operating conditions including pressures, vibrations, humidity, and temperatures expected for the intended application. Installation should be demonstrated in various blind or hard-to-reach maintenance scenarios and appropriate mistake-proofing tests will be required. A fit check on an appropriate aircraft platform is also a possibility. Testing should demonstrate improvement over the current design for seal reliability and installation success. Consideration shall be given to aerospace quality fluid line connection standards, codes, and specifications as appropriate. Partnering with an aerospace original equipment manufacturer (OEM) is recommended�though not required�to ensure product is suitable for aircraft usage and aid in future transition opportunities.

PHASE III DUAL USE APPLICATIONS: Transition opportunities by way of partnering with an aerospace OEM or military platform is recommended to ensure a smooth and efficient transition of the technology. A partnership can allow for installation testing and fit checks on the selected aircraft platform. Engine testing can also be used to simulate the operating environment of the chosen application. An engine Acceptance Test Procedure will provide a full life cycle of the engine environment, demonstrate full life for the seal, and provide opportunities to prove out the installation process. The OEM or military platform will dictate what further testing is required for the hardware to be incorporated.

Fluid connections are used throughout aerospace turbine engine, drive and mechanical systems, and aviation subsystem applications. These components in the military and commercial sector have high pressure fuel, oil, and hydraulic connections that are regularly touched for maintenance events. The technology developed under this topic is intended to be read-across to all similar high pressure fluid connections, ground ground-based applications as well, which could use improvements in reliability and ease of installation.


  1. Goobich, B., Thompson, J. R., & Trainer, T. M. (1967). Development of aluminum bobbin seals for separable connectors for rocket fluid systems. Battelle Memorial Inst Columbus Oh Columbus United States.
  2. Trainer, T. M., Baum, J. V., Thompson, J. R., & Ghadiali, N. D. (1969). Development of AFRPL flanged connectors for rocket fluid systems. Battelle memorial inst Columbus OH Columbus labs.
  3. Prasthofer, W. P. (1974, January). NASA Technical Memorandum: An assessment of separable fluid connector system parameters to perform a connector system design optimization study (Report No. NASA TM X-64849). Marshall Space Flight Center, Huntsville, AL, United States.

KEYWORDS: Seal; Fluid; Connection; Connector; Leak; Fitting


The Navy Topic above is an "unofficial" copy from the Navy Topics in the DoD 23.2 SBIR BAA. Please see the official DoD Topic website at for any updates.

The DoD issued its Navy 23.2 SBIR Topics pre-release on April 19, 2023 which opens to receive proposals on May 17, 2023, and closes June 14, 2023 (12:00pm ET).

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