When the Federal Aviation Administration (FAA) introduced the light sport aircraft (LSA) category in 2006, pilot and engineer Kirk Hawkins set out to create a simple, versatile LSA that would enable more people to experience the adventure of flying. He founded ICON Aircraft and, together with a team of experts, designed the ICON A5, an amphibious sport plane with folding wings that enable it to be stored in a shed, trailered behind a sport utility vehicle and launched from a shoreline – no airport required. With more than 100 ICON A5s in the market and about 50 more slated for production this year, Hawkins’ vision is coming to fruition, thanks to the characteristics of CFRP and ICON Aircraft’s serial manufacturing capabilities.
With the fuselage, wings, canopy and horizontal tail made completely from CFRP, the 2-seat ICON A5 weighs just 1,510 pounds. While the FAA limit for LSAs is typically 1,300 pounds, the A5 received an additional allowance to include cutting-edge safety features such as a spin-resistant airframe and a full aircraft parachute system. “Using carbon fiber composites was the intent all along because of what these materials offer. They are extremely lightweight but also have an impressive strength-to-weight ratio,” says Verónica Rubio, vice president of supply chain and manufacturing for ICON Aircraft. “The A5 would not have been possible as an LSA without the use of composites.”
The A5 has 375 individual CFRP parts, which are fabricated and bonded into assemblies and sub-assemblies at ICON’s facility in Tijuana, Mexico. Hand lay-up is used to place plies of Toray epoxy prepreg 2 x 2-foot twill fabric onto one of 250 different nickel-iron alloy and aluminum molds. Simple laminates, such as flat surfaces or brackets, have only a few plies, while complex parts, such as the wing spar, require up to 100 plies. Ninety-five of the composite parts utilize an aerospace-grade, closed-cell polymer foam core for rigidity. The lay-up process is laser guided because many of the parts have critical dimensions and require extremely accurate placement.
Following lay-up, the parts are vacuum bagged and cured in an oven (250 F for 100 minutes) or an autoclave (250 F with pressure ranging from 50 to 85 psi and varied cycle times). Once the curing process is complete, the CRFP parts are trimmed and drilled before they are bonded together into 77 assemblies and sub-assemblies. Next, these assemblies are sanded, painted and shipped to ICON’s Vacaville, Calif., facility for final assembly.