Problem Solved: Smiths Interconnect Hypertac Tackles Lightning Strike Threats

By Contributed Article | October 06, 2014

Significant changes are sweeping across the aviation landscape, forcing designers to take a more sobering look at protective measures against lightning strikes as the construction materials used in modern aircraft continue to advance.

commercial jetlinerThere’s no doubt in anyone’s mind that, in a heartbeat, lightning can be fatal. And while we all share a healthy respect for, and fear of, lightning, comprehending the awesome, split-second destructive power that lightning strikes unleash is all but incomprehensible to most of us. Actually being struck by lightning is something that rarely, if ever, enters the minds of the vast majority of air travelers. For the most part, people are pre-occupied with matters of getting to and from their destinations on time, and wondering if their luggage will arrive at the other end along with them.

However, looking at the phenomenon of lightning through the aviation reality lens, estimates from reliable sources indicate that virtually hundreds of aircraft are, in fact, struck by lightning every year. The very good news to be found in this unnerving
scenario is the fact that modern aircraft are designed and built to withstand lightning strikes. Truth be told, very few aircraft ever sustain major damage as a result of taking a lightning hit.

For the most part, this has been the norm. That said, significant changes are sweeping across the aviation landscape, forcing designers to take a decidedly more sobering look at the very real need to take new comprehensive protective measures
against lightning strikes as the construction materials used in modern aircraft continue to advance.

In fact, a new generation of composite material aircraft is being built by industry giants Boeing and Airbus that are lighter in weight, more fuel-efficient, and more environmentally friendly. These planes are ushered in as 21st-century replacements for the worldwide fleet of traditional metal-skinned aircraft. In the wake of transitioning to composite material aircraft, a daunting challenge facing design engineers today is one of addressing the problem of working with new materials that, in reality, offer substantially less protection against the potentially fatal effects of lightning strikes than their metal predecessors have provided in the past.

Where traditional metal-skinned aircraft act as a lightning rod, providing the lowest resistance for electrical discharges traveling from the sky to the ground, the same case simply does not hold true for the next generation of aircraft. There is a greater threat present in carbon fiber materials due to the fact that they are more prone to electrical surges. The intense atmospheric discharge of lightning current moving through the fuselage or across the wings of an aircraft, where the airframe is constructed of carbon fiber reinforced plastics (CFRP), has the power to burn right through such materials like a hot knife through butter. Again, this is not the case with metal and aluminum-skinned aircraft.

The most common approach employed by modern aircraft designers to reduce the damaging effects of electrical discharge on circuity has been the Faraday Cage, which is essentially a shield around the body of the aircraft that is constructed of conducting material. Such an enclosure around a plane has the effect of canceling out electrical fields outside the enclosure and protecting people and equipment on the inside. An updated version of the Faraay Cage has been designed into the composite material aircraft in development by Boeing and Airbus.

Additionally, the pressing need on the part of a manufacturer to deal with the thorny issues of higher voltage and impedance, though not critical in metal-bodied aircraft but potentially problematic in composite aircraft, is being addressed in the design process.

Today, a much greater degree of reliability, durability, immunity to shock and vibration, and the ability to address the threat of massive electrical surges is required by the industry. There is indeed a heightened sense of urgency around deploying on-board technology devices that will actually deliver and live up to the claims that are made relevant to their capabilities. The demands and requirements from design engineers are changing as they develop the next generation of lighter weight fuel-efficient aircraft.

A key technology element in the on-board equipment equation is that of electrical connectors, those small, unheralded components, often taken for granted, definitely play a very large role in meeting these unique and changing demands associated with doing business in the military and aerospace arena. A host of interconnect solution providers are responding to the industry’s call, and among them is Smiths Connectors Hypertac.

Today’s broad range of operating environments find many major systems providers manufacturing and marketing a wide array of solutions to the aerospace industry. In its role as a supplier to the aircraft design engineering community, one major systems
provider has forged a comprehensive technology alliance with Hypertac that has proven to be very successful when deployed in extremely harsh operating environments such as those where lightning strikes, causing surges that are a very real threat.

Hypertac’s unique “Basket of Wires” contact technology has been selected by one major systems provider as the interconnect solution of choice and is playing a key role as an instrumental element in the suite of on-board technology that is carried in composite material aircraft. Hypertac socket contacts are basically hyperboloid-shaped baskets of individual spring wires that are strung at an angle to the socket’s axis. The wire basket inside the female contact mates to a male pin, which, when inserted into the sleeve, results in the wires stretching around it, creating a number of  linear contact paths.

According to one lead design engineer, “For us, the decision to go with Hypertac was really the only one to make. We feel that the unique and innovative design of the Hyperboloid wire basket socket is the only one that delivers the extended contact area completely around the pin that we require from connectors in this environment.”

Smiths Connectors Vice President, Business Development and Strategy, Gabriel Guglielmi, says, “The basket of wires design guarantees an uninterrupted and continuous signal flow, and has delivered flawless performance in the most rigorous tests and real-world application environments. We are delighted to be collaborating with major systems providers and believe that we have unique strengths that work well with and compliment these companies.”

This case study originally appeared on Smith Connectors‘ website. To read the paper in full, click here.

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