Adam calls the carbon fiber technology used in his aircraft “second-generation.” It is a composite pre-impregnated with resin and supported by sandwiched honeycomb, similar to that used on the Raytheon Premier and Hawker 4000 business jets and what will be used on the Boeing 787 Dreamliner. Adam claims it yields a weight savings of 10 to 15 percent over comparable aluminum aircraft.
Not everyone building a very light jet is an aviation outsider. Linden Blue has been a leader in the industry for 30 years, beginning with Gates Learjet in 1977, where he was executive vice president and general manager. He has been a composites champion for most of that time, and especially since his directorship at Raytheon, when he supported the doomed but dazzling Starship twin turboprop (see “Beached Starship,” Aug./Sep. 2004). Since 1986, he has served as co-chairman of General Atomics, the company that makes the famous Predator series of unmanned aerial vehicles for the military. The Predator can stay aloft for 40 hours without refueling, thanks in part to its lightweight composite construction. Over the last 20 years, Blue has also been funding composite research, and in 1998 he formed Spectrum Aeronautical to take advantage of the technology.
“I've made so many mistakes,” he says, “it was just a matter of evolving the process over 20 years and getting it right.”
Spectrum toiled in secret until last fall when the wraps were taken off its 10-seat Model 33 jet. The company, which is run by Blue’s son, Austin, claims the 33 will have a range of 2,300 miles and cruise at 477 mph with the same hourly fuel consumption as the much smaller Eclipse. It will also be able to use ridiculously short runways. On its maiden flight from Spanish Fork, Utah (elevation 4,529 feet), last January 7, the 33’s reduced-power takeoff roll was just 750 feet, less than one-third of what a Cessna Citation CJ2 would require. (The same prototype crashed on takeoff from that runway last July 25, killing both test pilots. Preliminary investigations indicate that during a maintenance check, the flight control linkages were reconnected incorrectly.)
“After leaving Beech in 1984, I was convinced the Starship was a conceptually good airplane but poorly executed,” says Blue. “If you don’t automate composites, you lose control of weight and costs, and you can’t have a successful airplane. Raytheon was not ready to bite the bullet and do it right.”
Spectrum uses an automated method of fabricating carbon fiber called FibeX. It embeds fibers in the carbon material to provide stiffness and support, as opposed to the heavier honeycomb layer traditionally used. The entire fuselage section of the 33 weighs just 300 pounds. With full fuel and passengers, the Spectrum will weigh about 7,300 pounds, about half what a comparably performing aluminum business jet weighs. Before the recent crash of its lone prototype, the company said it would have its aircraft certified by 2008.
It takes optimism and courage—and perhaps the naïveté of an outsider—to create a new product category in an established industry. It also takes a lot of money. Very light jets will debut after almost 10 years and more than $2 billion worth of private and government-funded research and development.
The government funding came primarily through the Advanced General Aviation Transport Experiments (AGATE) program, which brought together some of the finest and most innovative aviation minds from NASA, industry, and the research community. Bruce Holmes, the associate director of NASA’s Langley Research Center in Virginia and the driving force behind the agency’s general aviation programs, has pushed to create a “highway in the sky,” a dream system that would make it as easy to fly an airplane as it is to drive a car. AGATE did not go that far, but it did lead to streamlining certification procedures for composite aircraft, new lightweight and fuel-efficient jet engines, and advanced and far more compact computer-based avionics that give pilots greater situational awareness and integrated real-time weather, terrain, and air traffic data. In avionics alone, the advances have been a dramatic improvement over the equipment in $40 million business jets that are just a few years old, claims ATG President Charlie Johnson.
Avidyne Corporation in Lincoln, Massachusetts, is providing flat-screen primary flight displays for ATG, Adam, Eclipse, and Spectrum jets. The display combines navigation data along with airspeed and rates of climb or descent. The integrated cockpit displays are fed by sophisticated electronic sensors, as opposed to old-style mechanical gyroscopes and accelerometers. The displays not only provide better pilot guidance, but also are lighter, cheaper, and easier to install and maintain than traditional “steam gauge” instruments.
“These electronics weigh less primarily because there are so many fewer wires and connectors and switches,” says Avidyne CEO Dan Schwinn.