There is a company in the United States that specializes in the design and manufacture of fuel gauges for rotary-wing and fixed-wing aircraft. Its offering includes a range of capacitive fuel gauging probes, each consisting of two concentric carbon fiber composite tubes that act as two conductive plates between which a dielectric current flows.
The company manufactures all of its fuel gauge tubes on-site using a roll-to-roll process in which plies of prepreg are rolled up by hand and glued to a mandrel, then cured in an oven. Before assembly, the tubing is unraveled, cut to length, and machined to a uniform diameter and wall thickness. For the tubes, it chose carbon fiber prepreg with a proprietary resin system for its excellent mechanical and electrical properties, as well as its resistance to the corrosive and oxidative effects of jet fuel.
Using carbon fiber composites to make these parts weighs 40 percent less than aluminium. Plus, the composite resists dents, scratches, cracks and corrosion, and won't absorb hand oils, which can affect performance. Aluminum tubes also need to be riveted to the probe's electronics, which can wear out over time due to friction, while composite tubes can be bonded to electrical components.
Carbon Fiber Fuel Gauge Probes offer options for a range of aircraft fuel tanks. Recently, the company decided to develop a product specifically for small aircraft, aiming to achieve greater safety, greater precision and greater reliability in a small fuel tank.
