INCORPORATING WEIGHT-SAVING TECHNOLOGY IN AEROSPACE APPLICATIONS: AT WHAT RISK?

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1 INCORPORATING WEIGHT-SAVING TECHNOLOGY IN AEROSPACE APPLICATIONS: AT WHAT RISK? John Kuster, Senior Product Manager Harnessing Products TE Connectivity Aerospace, Defense & Marine Republished by Aerospace & Defense Technology AEROSPACE, DEFENSE & MARINE /// BYLINE ARTICLE -

2 INCORPORATING WEIGHT-SAVING TECHNOLOGY IN AEROSPACE APPLICATIONS: AT WHAT RISK? John Kuster, Senior Product Manager Harnessing Products The drive to incorporate the latest weight-saving technologies in electronic systems is not new. Microelectronic packaging has been packing more power in less size since the invention of the integrated circuit. This has allowed sophisticated systems to move from floor level to desktop to handheld while offering more sophisticated capabilities. Now new advances in polymers are allowing other, more traditional components to offer such savings. Although of immense benefits, launching these lighter components into production can carry unseen risks for those inexperienced in the underlying science. The pitfall is moving too quickly and too aggressively into areas outside of your core competencies. It is often better to rely on partners who already have deep expertise, which can reduce risk and help ensure a smooth transition from concept to production. The desire to save space and weight makes sense in military and aerospace applications if you consider the simplified definition of work: Work = Mass x Distance. Reducing mass means less energy expended to do the work. The lighter something is the less energy required to move it, whether it is a ground vehicle or an aircraft in the sky. Size and weight, of course, are related in reducing mass. For an unmanned aerial vehicle, lower weight components means longer times aloft and greater fuel efficiency. Consider that the Global Hawk UAV contains about 850 pounds of cable. Lighter weight cable, connectors, and harnessing components can play a significant role in weight reduction. Launch costs to put a satellite in orbit can range from $5000 to $50,000 per pound of payload. Any reduction in weight can significantly influence costs or allow extra weight for additional scientific and engineering equipment or more maneuvering fuel to extend the life of the mission. The hardware designer has unique performance requirements to consider when specifying RF/microwave relays and switches. Signal-level DC and low-frequency AC relays are typically characterized using different specifications than those used for RF/microwave. But the attributes can be compared. One reason for the difference is that the characteristics of microwave relays are frequency dependent Evolution of Established Technologies Established technologies continue to evolve to meet new demands and overcome past limitations. New lightweight composite materials are an example. Today s composites have greater strength and durability to make them a desirable replacement for metal. Electronic enclosures demonstrate the advances being made. A high range of fillers ranging from traditional carbon fibers to newer microspheres and carbon nanotubes allow a great deal of flexibility in tailoring an enclosure s properties to meet a variety of mechanical, environmental, and electrical requirements. AEROSPACE, DEFENSE & MARINE /// BYLINE ARTICLE PAGE 2

3 Traditionally, composites have reduced connector weight by around 40 percent. By optimizing the reinforcing material and introducing foam into polymer matrices, an additional 10 to 20 percent savings can be reached. Not only the fiber material but also the length of the reinforcing fibers play a significant role in determining the strength of the finished part. Higher strength materials can mean reduced wall thickness and hence lower weight. Introducing foaming agents or microspheres into a polymer composite although made more difficult as the reinforcing fiber volume increases is now possible. Requirement Strength enhancement Weight reduction EMI shielding and electrical conductivity Fluid resistance Tolerance to extreme temperatures Example approaches Chopped glass or carbon fiber composites Continuous fiber composites Hollow microspheres Foaming agents Chopped glass or carbon fiber composites Continuous fiber composites Carbon fiber composites Nickel-plated carbon fiber composites Carbon nanotube composites Engineered thermoplastics and coatings Engineered thermoplastics Figure 1. Composites can be formulated to meet a wide variety of application needs (Source: TE Connectivity) Wires and cables continue to get lighter. Aluminum, once overlooked because of reliability concerns with cold-creep at terminations, is gaining momentum with more compatible lugs and splices becoming available. Since aluminum has only 60 percent the conductivity of copper, a larger conductor is needed to achieve the same current-carrying capacity. Even accounting for this, aluminum will be about half the weight of copper. Even more intriguing is the prospect of carbon nanotubes (CNT) wire and cable. TE is one of the companies at the forefront of commercializing CNT cable technology. Engineered polymers also contribute savings. Cross-linked insulation and jacket materials allow thinner walls and lighter weight. They are also tough and durable, resisting abrasion, solvents and chemicals, and temperature extremes. They can offer continuous operation at temperatures of 200 C and beyond. Heat-shrinkable harnessing components have also shed weight. TE recently introduced molded parts that are up to 30 percent lighter without sacrificing temperature or fluid-resistant performance. New designs in copper braid offer up to 50 percent lighter constructions than their predecessors. Make or Buy: The Challenge of New Technology Conventional design rules are thrown out as new platforms are given seemingly unattainable targets for weight and performance. The aerospace industry, among others, is starting to be concerned and are starting to regulate safety of newer nonconventional electrical systems through programs such as EWIS (Electrical Wiring Interconnection Systems) in the commercial aerospace industry. Companies may be more successful in meeting the demand for smaller, lighter, more powerful electrical systems if they have a foundation in the core competencies that lead to innovative solutions in these areas. Material science in many cases provides the solutions for reducing weight and adding strength, temperature resistance and environmental sustainability in new electronic circuits. Some find it is less expensive and more efficient to tap the expertise of companies that specialize in the technologies AEROSPACE, DEFENSE & MARINE /// BYLINE ARTICLE PAGE 3

4 you want to incorporate into new designs. Many of the advances rely heavily on material science to create new solutions. Let s use composite enclosures as an example. As a connector company, TE has extensive experience in composites for military and aerospace applications and in molded parts and adhesives for backshells and harnessing. One result is robust research in these areas is developing composite formulations and manufacturing technologies to allow high-volume, cost-effective manufacture of composite enclosures. TE has also created reliable methods of selective metallization of the composites. Selective metallization allows circuit traces, shielding, and even embedded antennas to be cost-effectively integrated into the enclosure. In short, the core competency embraces both materials science and manufacturing. Figure 2. Composites, combined with selective metallization, provide a lightweight, durable alternative to metal enclosures (Source: TE Connectivity) A composite enclosure should not be designed as a straight replacement for aluminum. Rather the enclosure should be designed for higher functionality and efficient molding and metallization. DC and RF circuits, strain sensors, mechanical retention features, electrical connectivity, and even connector housings can be integrated into the design. Owning core competencies is not essential. You can rely on suppliers who have that competency. Not only can developing a core competency be expensive and risky, it becomes increasingly difficult to achieve competency in all the technologies a company needs. In a world of finite engineering resources, do you want to concentrate on your own formidable competencies or take the risk of developing competencies that are not central to your business? The risks of developing new competencies in-house include delays due to unforeseen design and manufacturing obstacles, higher testing costs, and even failure to achieve goals. TE recently worked with an aerospace manufacturer to develop a grounding system for composite airframes. Composite airframes require new thinking about grounding and bonding to replace traditional approaches suited to metal airframes. The new thinking requires a system-level approach that embraces connectors and backshells, harnessing, raceways, and aircraft structural elements all legacies competencies that TE had. An additional competency sometimes overlooked is the skill at integration. The future can arrive in short steps. Solutions for future platforms do not have to be obtained in giant leaps in technological advancement. Small improvements and sustained, planned, steps with new materials and technologies may be the right approach for reducing risk of time-to-market failures or performance issues associated with totally new ideas and technology. Whether it is the design of a powerful battery for emergency power or a lightweight wearable radio for the soldier of the future, lighter, smaller and more powerful are always going to be driving design goals. Companies that use a sustainable approach, based upon core competencies and experience in the market can expect to reach those goals with a higher degree of success and lower risks of failure or customer dissatisfaction. AEROSPACE, DEFENSE & MARINE /// BYLINE ARTICLE PAGE 4

5 Author s Bio John Kuster is senior product manager for TE Connectivity s Global Aerospace, Defense, and Marine business unit. John holds degrees in both industrial engineering and systems engineering. John has over 30 years experience in the electrical interconnect field, specializing in electrical cable systems, heat shrinkable polymers and electrical harness systems. te.com Legal. TE, TE Connectivity, TE connectivity (logo) and Tyco Electronics are trademarks of the TE Connectivity Ltd. family of companies and its licensors. While TE Connectivity has made every reasonable effort to ensure the accuracy of the information in this document, TE Connectivity does not guarantee that it is error-free, nor does TE Connectivity make any other representation, warranty or guarantee that the information is accurate, correct, reliable or current. TE Connectivity reserves the right to make any adjustments to the information contained herein at any time without notice. TE Connectivity expressly disclaims all implied warranties regarding the information contained herein, including, but not limited to, any implied warranties of merchantability or fitness for a particular purpose. The dimensions in this document are for reference purposes only and are subject to change without notice. Specifications are subject to change without notice. Consult TE Connectivity for the latest dimensions and design specifications TE Connectivity Ltd. family of companies. All Rights Reserved. AEROSPACE, DEFENSE & MARINE /// BYLINE ARTICLE PAGE 5