For a small company, VX Aerospace of Morgantown, N.C., thinks big – as big as major aerospace manufacturers. Thanks to advances in computer-aided design (CAD), CNC machining and composite materials, the gap in capabilities between the “big boys” like Boeing and Northrop Grumman and small aerospace companies such as VX Aerospace is narrowing, says Robert Skillen, CEO of VX Aerospace. “Little companies can do interesting things now that you used to think could only happen at large companies,” he says. VX Aerospace’s latest development is the VX-1 KittyHawk™ aircraft, a “blended wing” aircraft that combines the fuselage and wings and resembles a manta ray. According to the company, the design – which incorporates Chomorat’s C-PLY™ carbon multiaxial product – allows for more useable space inside the aircraft, greater payload capacity, better structural efficiency and better durability. The VX-1 KittyHawk is the first aircraft to incorporate C-PLY, which has been used in the automotive industry, most notably for fenders on the Audi RS3 Sportback. The non-crimp fabric is comprised of unidirectional layers that are mechanically sewn together. It can have plies with a tow spreading process resulting in thicknesses as low as 75 gsm (grams per square meter) and can make very shallow angles (between ± 20 and ± 30degrees).
For small businesses doing aerospace grade work, C-PLY isa “game changer,” says Skillen, especially because it allows for shallow angles without automatic tape placement. This, in turn, saves the company “hundreds of thousands – if not millions of dollars – in investment, which is beyond the reach of a small business,” he says. VX Aerospace got in on the ground floor with the new C-PLY material by partnering with Chomorat as a test manufacturer for the past several years.
VX Aerospace began developing the VX-1 KittyHawk in 2012 after the U.S. Marines retired the H-46 model helicopter, for which it had manufactured parts. Skillen began casting around for a new product.Inspired by blended wing military aircraft and other airliners, he turned his eye to a blended wing aircraft for the light and unmanned aircraft markets.
Skillen designed the VX-1KittyHawk using CAD – yet another tool he says has closed the gap between small and large aerospace companies. “Twenty years ago, ifyou had to do CAD modeling to a millionth of an inch or something,the only people that could do tha twere large companies and it cost hundreds of thousands, if not more,” he says. “Now I operate a $3,700 CAD program that does fantastic surface modeling.” Last October, Skillen brought the aircraft idea to North Carolina State University, where it was quickly selected by Lars Soltmann, a postdoctoral student, for his thesis project on the performance prediction and evaluation of the KittyHawk. After Soltmann’s computational fluid dynamics and wind tunnel testing showed promising results, VX Aerospace developed a 6 x 7-foot quarter-scale prototype, which was displayed atJEC Europe in March.Skillen didn’t want to invest in high-temperature tooling for the prototype, so the tools were direct-machined out of 39-pounddensity tooling plastic. C-PLY was then laid up in molds, vacuum infused with epoxy and cured at room temperature for 24 hours. (Production versions will use high-temperature tooling and C-PLYfabrics with Cytec MTM® 45-1 prepregs.)