The Department of Defense, specifically the U.S. Air Force, is seeking proposals for the Small Business Innovation Research (SBIR) topic titled "3000F Oxidizing Extreme Combustion Environment Fiber/Filaments And Rope Seals." The objective is to develop and demonstrate new fibers or filaments, surface treatments, or coatings that can withstand extreme temperatures of over 3000°F for at least one hour, while also being capable of being fabricated into rope seals for use in hypersonic propulsion systems. These rope seals are critical for maintaining the integrity of high-temperature environments in future Air Force hypersonic flight and propulsion systems, where existing materials have proven inadequate. Proposals are due by May 21, 2025, and interested parties can find more information and submit their applications through the provided link: [SBIR Topic Link](https://www.sbir.gov/topics/11920).

OUSD (R&E) CRITICAL TECHNOLOGY AREA(S): Hypersonics 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: The topic requests that prospective proposers develop and demonstrate either a new resultant fiber/filament, a surface treatment of a fiber/filament, a coating on said resultant fiber/filament, or whatever approach creates a resultant fiber/filament that is capable of surviving the following conditions: Exposure to hot combustion gases of temperatures of at least 3000°+F without unacceptable property degradation. Exposure to the above hot gases for at least 1 hour without undue usable property degradation. Multiple exposures to the above hot gases for 1 hour durations without undue usable property degradation. The resulting fiber/filament must also meet the above requirements while also being capable of being fabricated into rope seals. DESCRIPTION: The topic will request that prospective proposers develop a fiber/filament/surface-treatment/coating final resultant fiber/filament capable of, whence fabricated into a rope seal, repeated extreme temperature (3000°F) operations in high heat flux, oxidizing environments for at least 1 hour. Existing Air Force Flight and Propulsion systems extensively use rope seals most ubiquitously capable of high temperature 1000 to 1500 °F environment applications. Unfortunately, none of the rope seals now available or being investigated for Air Force eventual use are capable of surviving exposure to the 3000&gt;°F propulsion environment anticipated to be experienced by Hypersonic systems for at a minimum of 1 hour. As per Dr Weber’s and Dr Johnson’s (both in OUSD(R&E) DDRE Hypersonics and JHTO) May 2020 presentation, future Air Force Hypersonic Flight and Hypersonic Propulsion Systems will require repeated long operations times (hours), durable, resilient rope seals that can operate in high heat flux, oxidizing environments and restrict the flow of hot gases at extreme temperatures (3000&gt;°F) in static interfaces. Static seal locations include interfaces between leading edges and wings, integration of an aperture and interfaces between thermal protection system elements and engine components. As these rope seals are made out of fibers/filaments these resultant fibers/filaments must first meet these same requirements along with being able to be fabricated into rope seals. The proposer shall provide an exhaustively detailed report incorporating substantiating previous experimental results and detailed technical explanations as to why the new approach/material will accomplish the topic&#39;s performance objectives. The proposer will provide detail and documentation in the Direct to Phase II proposal which demonstrates accomplishment of a “Phase I-like” effort. This includes determining, insofar as possible, the scientific and technical merit and feasibility of ideas appearing to have commercial potential. It must have validated the product-market fit between the proposed solution and a potential AF stakeholder. The proposer shall produce a defined, clear and immediately actionable plan with the proposed solution and the AF customer. The proposer shall sufficiently develop the technical approach, product, or process in order to make a sufficient amount of the resultant fiber/filament and subsequent Rope Seals to conduct property change with exposure to hot combustion gases of temperatures of at least 3000°+F for at least 1 hour testing. The proposer shall conduct sufficient tests on the exposed fiber/filament and rope seals fabricated from the material to determine rope seal relevant property changes capable of achieving the performance characteristics detailed in the topic’s performance objectives. These tests will include but not be limited to but must include dimension changes, weight changes and mechanical property changes. The tests shall demonstrate that the fiber/filament material can achieve the performance characteristics detailed in the topic’s performance objectives and be documented as such in a detailed stand alone report. The proposer shall deliver whence the proposed fiber/filament material has been fabricated into a testable rope seal form to a government acceptable Government test facility for independent performance characterization testing detailed in the topic’s performance objectives paid for by the proposer. The tests shall substantiate that the new fiber/filament – rope seal can achieve the performance characteristics detailed in the topic objective and be documented as such in a detailed stand alone report. With the best test performing fiber/filament material the proposer shall fabricate a sufficient amount of the fiber/filament material and fabricate it into actual rope seals by making five circular cross section circular overall diameter O ring style rope seals. 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, shall be documented. PHASE I: The proposer shall provide an exhaustively detailed report incorporating substantiating previous experimental results and detailed technical explanations as to why their new approach/material will accomplish the topic's performance objectives. The proposer will describe and document previously conducted work which has demonstrated the successful creation of a demo prototype rope or pillow like seal made from either the 3000F fibers of topic interest or fibers capable of being exposed to high 2700+F OR has demonstrated production techniques with high 2700+F fibers which will be needed to successfully fabricate demo prototype rope or pillow seal made from the rather brittle 3000F type fibers. PHASE II: The proposer shall sufficiently develop the technical approach, product, or process in order to make a sufficient amount of the resultant fiber/filament and subsequent Rope Seals to conduct property change with exposure to hot combustion gases of temperatures of at least 3000°+F for at least 1 hour testing. The proposer shall conduct sufficient tests on the exposed fiber/filament and rope seals fabricated from the material to determine rope seal relevant property changes capable of achieving the performance characteristics detailed in the topic’s performance objectives. These tests will include but not be limited to but must include dimension changes, weight changes and mechanical property changes. The tests shall demonstrate that the fiber/filament material can achieve the performance characteristics detailed in the topic’s performance objectives and be documented as such in a detailed standalone report. The proposer shall deliver whence the proposed fiber/filament material has been fabricated into a testable rope seal form to a government acceptable Government test facility for independent performance characterization testing detailed in the topic’s performance objectives paid for by the proposer. The tests shall substantiate that the new fiber/filament – rope seal can achieve the performance characteristics detailed in the topic objective and be documented as such in a detailed standalone report. With the best test performing fiber/filament material the proposer shall fabricate a sufficient amount of the fiber/filament material and fabricate it into actual rope seals by making five circular cross section circular overall diameter O ring style rope seals. 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, shall be documented. 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. Rajakkannu Mutharasan, Bruce Steinetz, Xiaoming Tao, Guang-Wu Du and Frank Ku, “Development Of Braided Rope Seals For Hypersonic Engine Applications: Flow Modeling.”, NASA Technical Memorandum 105942, pages 1-26, December 1992 2. Bruce M. Steinetz, Michael L. Adams, Paul A. Bartolotta, Ram Darolia and Andrew Olsen, “HIGH TEMPERATURE BRAIDED ROPE SEALS FOR STATIC SEALING APPLICATIONS”, NASA Technical Memorandum 107233, Pages 1-13, November 1996 3. Bruce M. Steinetz and Michael L. Adams, “Effects of Compression, Staging and Braid Angle on Braided Rope Seal Performance”, NASA Technical Memorandum 107504, Pages 1-14, July 1997 4. Bruce M. Steinetz and Michael L. Adams, “Effects of Compression, Staging and Braid Angle on Braided Rope Seal Performance”, NASA Technical Memorandum 107504, Pages 1-14, July 1997 5. Patrick H. Dunlap, Jr., Bruce M. Steinetz, Donald M. Curry, Jeffrey J. DeMange, H. Kevin Rivers and Su-Yuen Hsu, “Investigations of Control Surface Seals for Re-Entry Vehicles”, 6. NASA/TM--2002-211708, Page 1-29, July 2002 7. Jeffrey J. DeMange, Patrick H. Dunlap and Bruce M. Steinetz, “Improved Seals for High Temperature Airframe Applications”, NASA TM 2006 214465, Pages 1-26, October 2006 8. Shawn C. Taylor, Jeffrey J. DeMange, Patrick H. Dunlap Jr. and Bruce M. Steinetz, “Further Investigations of High Temperature Knitted Spring Tubes for Advanced Control Surface Seal Applications”, NASA TM 2006 214348, Pages 1-25, November 2006 9. Jeffrey J. DeMange, Patrick H. Dunlap, Bruce M. Steinetz, and Gary J. Drlik, “An Evaluation of High Temperature Airframe Seals for Advanced Hypersonic Vehicles”, NASA TM 2007 215043, Pages 1-25, October 2007 10. Patrick H. Dunlap Jr, Bruce M. Steinetz, Jeffrey J. DeMange and Shawn C. Taylor, “Toward an Improved Hypersonic Engine Seal”, NASA TM 2003 212531, Pages 1-25, July 2003 11. Pat Dunlap, “Overview of High Temperature Seal Development at NASA GRC”, NASA Glenn Research Center, Presentation, December 8, 2021 12. Pat Dunlap, Bruce Steinetz, Josh Finkbeiner, Jeff DeMange, Shawn Taylor, Chris Daniels and Jay Oswald, “AN UPDATE ON STRUCTURAL SEAL DEVELOPMENT AT NASA GRC”, 2005 NASA Seal/Secondary Air System Workshop, November 8-9, 2005 13. JAY JOSEPH OSWALD, “MODELING OF CANTED COIL SPRINGS AND KNITTED SPRING TUBES AS HIGH TEMPERATURE SEAL PRELOAD DEVICES”, MS THESIS, CASE WESTERN RESERVE UNIVERSITY, May 2005 14. Bruce M. Steinetz, “Seal Technology For Hypersonic Vehicles And Propulsion Systems: An Overview”, Short Course On Hypersonics Structures And Materials, Feb 2008 15. J. Perepezko and R. Sakidja, Extended Functionality of Environmentally Resistant Mo-Si-B Based Coatings; JOM, V65, N2, 2013 16. V. Zmii, N. Kovtun, P. Glushko and S. Ruden; Stability and Heat Resistance of Silicone Coatings on Refractory Metals II. Stability and heat resistance of Silicide coatings on tungsten and molybdenum at 1500-2000C&quot; Powder Metallurgy and Metal Ceramics, V42, N1-2, 2003 17. J. Perepezko and R. Sakidja, Oxidation-resistant coatings for Ultra-high temperature refractory Mo-based alloys; JOM V62, N10, Oct 2010 18. Patent Filing: assigned to ACF, LLC: “Methods of Producing Silicon Carbide Fibers, and Articles including same”, Inventors: J. Garnier and G. Griffith and Methods of Producing Metal Carbide Fibers”, USP 8,940,391 19. T.Shimoo,F.Toyada,K.Okamura. Thermal Stability of Low-Oxygen Silicon Carbide Fiber (Hi-Nicalon) Subjected to Selected Oxidation Treatment. J.Am.Ceram.Soc.81(2000)1450-1456. 20. S.J.Wu, L.F.Cheng, L.T.Zhang, Y.D.Xu ,et al.Wet oxidation behaviors of Hi-Nicalon fibers.Appl.Surf.Sci.253(2006)1447-1450. 21. R.Q.Yao,Z.D.Feng,L.F.Chen,et al.Oxidation behavior of Hi-Nicalon SiC monofilament fibers in air and O2–H2O–Ar atmospheres. Corros. Sci.57(2012) 181-191. KEYWORDS: Fiber; Filament; Rope Seal; Hypersonic; Scramjet; Rotating Detonation Engine; 3000F; Rotating Detonation Rocket Engine

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