In June 2010, the U.S. Army took a chance by investing in a hybrid blimp/plane/helicopter for its Long Endurance Multi-intelligence Vehicle (LEMV) project. Known as the HAV304, the aircraft was built by Bedford, U.K.-based Hybrid Air Vehicles (HAV) with Northrop Grumman as the prime contractor. Once successfully operational, the Army hoped the aircraft would provide intelligence, surveillance and reconnaissance support for ground troops.
Unfortunately, the HAV304 never reached that point. In 2012, just 25 months after the start of its contract, the aircraft had its first test flight and only flew for 90 minutes. It was deemed unsuccessful for the Army’s needs, so the following year the Army cancelled the LEMV project and the aircraft was bought back by the U.K.
Since then, HAV has won £6 million in grants from the U.K. and the European Union and raised £2.4 million from public crowdfunding to give the hybrid aircraft a second life. HAV officially began its “Return-to-Flight” program in May and gave the HAV304 a new name – the Airlander 10. (The “10” refers to the aircraft’s ability to carry ten tons.) Unlike its previous iteration, this one will be used for more than just military purposes. It also will have commercial applications, such as tourism, cargo transportation, border security and infrastructure surveillance.
The Airlander 10 will incorporate lighter-than-air technology to create what the company calls “a new breed of hyper-efficient aircraft.” The aircraft will get 60 percent of its lift from internal helium gas and 40 percent from its aerodynamic form. A critical component of the success of the aircraft is the boost it gets from advanced composite materials.
“The Airlander hull is made of a flexible laminate utilizing Vectran® as the structural fiber,” says Ashley Appleton, head of rigid structures at HAV. “The laminate contains specific features to protect the material from the environment and to retain helium.”
The skin of Airlander 10’s hull is a combination of five tons of multilayered Vectran weave, Tedlar® and Mylar™ surrounding a helium bubble. This provides strength and endurance that past hybrid aircraft prototypes lacked. According to vectranfiber.com, Vectran, which consists of a high-performance multifilament yarn spun from liquid crystal polymer, is five times stronger than steel and 10 times stronger than aluminum. Tedlar is a polyvinyl fluoride film that provides an outer coat and protects the hull from wearing away. Mylar, a form of polyester resin used to make heat-resistant plastic films, creates a gas barrier to minimize helium loss.
The hull is not the only structure on the revitalized aircraft to rely on composites. The engine frames also were made from an undisclosed carbon fiber prepreg. Underneath the Airlander 10 is a 149-foot-long structure made with CFRP and GFRP materials supplied by Cytec Industries. The structure contains the flight deck, services area, payload bay and a forward fuel tank.
