Showcasing a wide selection of high-performance solutions during the Farnborough Airshow last July, one thing that really caught my eye on its stand was Gore’s Cable Installation Simulator.
When it comes to testing the tensile stress of aircraft cabling, the amounts of technical customer documents I’ve read through in my previous life as a manufacturing engineer, working for a well-known Tier 1 aerospace company, still gives me nightmares to this day!
Proven in the real world and trusted for decades, Gore’s high-performance solutions for aerospace and defence applications ensure connection, protection and safety every time in the most demanding environments.
On display at the Farnborough Airshow were its durable, compact and highly-flexible GORE Aerospace Cables including high data rate, power/signal delivery, and coaxial and microwave/RF solutions for aircraft and spacecraft applications. Also highlighted were EMI shielding solutions that provide excellent RF grounding and shielding performance in aircraft.
Simulate to innovate
To minimise the risk of cable assembly damage or failure during installation, Gore has developed a Cable Installation Simulator to evaluate the stress of installation on microwave airframe assemblies. By comparing signal integrity before and after installation, Gore can engineer assemblies that withstand airframe installation as well as the demands of the aircraft’s flight envelope.
Nearly one-third of cable failures occur during installation, so this is a crucial risk factor to minimise. Damaged airframe assemblies can lead to compromised signal integrity and failures over time, as well as additional testing, maintenance and replacement costs.
With the new Cable Installation Simulator, military and civil aircraft manufacturers can be confident they are getting a reliable cable assembly solution that withstands the rigors of installation and reduces the total cost of ownership.
Prior to installation in the simulator, new cable assemblies are tested to verify the insertion loss and voltage standing wave ratio (VSWR) over a given frequency range. This information serves as the baseline to evaluate any performance change after being routed through the simulator. Gore's Cable Installation Simulator replicates the conditions a cable assembly experiences while being routed during installation in an aircraft.
The device uses four mandrels to simulate routing an assembly around the internal structure of an airframe. The mandrels replicate MBR conditions that the assembly will encounter in an aircraft. Several routing guides are used to induce torque into the assembly as it is pulled through the simulator. Next, the assembly is pulled through an abrasion bar to simulate routing across sharp edges or through access holes in the airframe structure.
After being fed through the Cable Installation Simulator, the assembly is ready for testing. The assembly is connected to a vector network analyser (VNA) to test the insertion loss and VSWR, and the results are compared to the baseline results of the assembly tested prior to installation. Depending on the results of the test, the assembly may be routed through the simulator multiple times and re-tested to verify its durability.
Use of the Installation Simulator gives aircraft manufacturers and installer’s evidence that their assemblies will provide the same level of electrical performance after installation as when they are brand new. And they can be assured that the assemblies will continue to perform reliably throughout the service life of the aircraft.
Solutions fit the bill
Aircraft manufacturers need reliable solutions that can be installed deep within an aircraft and left there for the life of the platform. Therefore, we want to create 'fit and forget' solutions that will survive the demanding environments within an aircraft.
“We have approached our end users to understand exactly how they install and package their cables inside an airframe,” explains Gore’s business development aerospace and defence associate, Tim McMullen. “We have found that they actually exert 30-40lbs of tensile load on the cable during the install process when routing it through various bulkheads – and through sharp bend radii - to eventually connect it up to the back of a rack. If you take a typical RF cable, and put it through an aircraft structure, something will eventually fail. These RF cable installation challenges drastically change the cable’s electrical performance.”
In terms of interconnect marketplace challenges Gore has quickly realised the effects on the cable during installation and the need to educate the industry by introducing its Cable Installation Simulator. Elsewhere, its Microwave/RF assemblies, and particularly its 6 Series products are said to provide stable and accurate performance over the aircraft’s lifespan. The rugged 6 Series is able to easily tolerate rigorous installation, and the use of fluoropolymers used in its construction reduces abrasion caused by routing.
“We have really focused on developing our microwave/RF assembly products,” McMullen concludes. “Our 6 Series products possess a high tensile strength, good abrasion resistant outer jackets, a series of crush resistant layers and moisture barriers, so that they can be routed through an aircraft structure whilst at the same time maintaining the same electrical performance after installation.”
Gore is committed to designing next generation products that solve key challenges, and mitigate risk for aircraft by testing and simulating ‘real world’ conditions that ensure its products do what they say they will do, consistently, reliably and even in harsh conditions. Had the Gore Cable Installation Simulator been around when I was working in the industry, I would have had many more good night sleeps!