The Next Little Thing | Flight Today | Air & Space Magazine
Honda's in! As announcements go, this was a whopper. More than 15 years of development preceded Honda's decision, trumpeted at this year's Oshkosh, Wisconsin fly-in, to build the HondaJet. Most attentive listeners? Other jet builders. (American Honda Motor Co.)

The Next Little Thing

Why 2006 is the year of the very light jet.

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At the world’s largest gathering of propeller-driven airplanes, this year’s big news was jets. A whole new class of jet aircraft, very light jets, dominated the general aviation exhibits at the Experimental Aircraft Association’s Oshkosh, Wisconsin airshow. No fewer than seven companies—Adam, ATG, Cessna, Diamond, Eclipse, Embraer, and Honda—had little jets, or mock-ups of them, on display, and there was buzz at every booth.

As a class, VLJs incorporate significant advances in airframe design, engines, computerized avionics, manufacturing techniques, and materials. The advances, developed mainly over the last decade, make these small aircraft easier to operate than jets of the previous generation and—even with jet fuel now hovering around $4 a gallon—more affordable to fly. The new class consumes half the fuel that older corporate jets do, so many more pilots can afford to own jets today than could a decade ago. The Federal Aviation Administration predicts that 4,500 light jets will be flying by 2016. (To put the potential impact of VLJs in perspective, consider this: There are 15,000 business jets currently operating worldwide, and Cessna, the most prolific manufacturer of them, plans to deliver 290 this year.) When FAA Administrator Marion Blakey awarded the Eclipse Model 500 provisional certification at Oshkosh last July—timing that contributed to the fanfare—she said, “This is a real game-changer for our industry.”

The rules of that game actually began changing as early as 1970, when Cessna introduced the Citation, a “slow” 400-mph jet that made it possible for pilots who had been flying 300-mph twin turboprops, like the popular Beech King Air, to step up. Transitioning to a 100-mph-faster airplane that could fly about 10,000 feet higher than the airplanes private pilots were accustomed to wouldn’t demand as much training (or money) as would be required to fly the 500-mph jets with 40,000-foot ceilings that populated the inventory at the time (see “Getting Up to Speed,” p. 56). Within a decade, the Citation stole much of the twin turboprop market. Today, Cessna Citations account for one-third of all new business jet sales. (Cessna has also jumped into the very light jet market with its six-seat, 390-mph Citation Mustang, which is on track for certification later this year, but CEO Jack Pelton resists calling it a VLJ; rather, he labels it a “downward expansion of the product line.”) The Citation brought more pilots into the jet fold. Enticing even more would mean finding the next niche: a jet even cheaper and easier to operate than the Citation.

While the Citation was causing a small upheaval in business aviation, engine maker Sam Williams was working on small turbofans, the least fuel-hungry type of jet engine operating today, to power cruise missiles. Williams believed the little engines might create the next general aviation niche. “He always thought anyone who could fly would prefer to fly a jet,” says Matt Huff, vice president of business development for Williams International. Huff says that the turbofan technology developed for cruise missiles did not directly carry over to the family of powerplants Williams eventually designed for today’s VLJs, but adds, “We did learn an awful lot of lessons from the cruise missile program that helped us when we decided to go into general aviation.”

An interim step was the 2,300-pound-thrust FJ-44 turbofan. The engine entered commercial service in 1993 and to date Williams has produced 2,400.

But Williams believed the real production increases would come when a significant percentage of private pilots flying piston-powered twin-engine aircraft (18,469 airplanes in the United States, according to the FAA) could transition into a new category of light jets. In 1996, the company partnered with NASA’s General Aviation Propulsion Program. Conducted by the Glenn Research Center in Ohio, the program was one of several NASA-sponsored efforts to revitalize the sagging U.S. general aviation industry. Williams said in a company press release the following year: “Our objective is to replace aging, piston-powered light aircraft with all new, four-place single and six-place twin, turbofan-powered modern aircraft. This means we must develop a turbofan in the 700-pound thrust category that is very low in cost at a high production rate, is extremely quiet, is light in weight, and is very reliable.”

Williams had hired Burt Rutan to build a demonstration aircraft, the V-JET II, to showcase his new engine. The V-JET, looking the part of the revolutionary, made its first public flight at Oshkosh in 1997. Built of composite materials, the aircraft had a V tail, a nose shaped like a fighter’s, forward-swept, drooping wings, and a portal windshield. It was extremely quiet thanks to the pair of experimental 550-pound-thrust, low-pressure Williams FJX-1 engines it was built for.

One of the first true believers the V-JET called to the cause was Vern Raburn, today the CEO of Eclipse Aviation. Raburn, a 7,000-hour jet-rated pilot who had held senior executive positions at Microsoft, Lotus Development, Symantec, and Slate, founded Eclipse in 1998 after several discussions with Sam Williams. The company’s original engineering team was for a time housed at Williams’ headquarters.

The Eclipse-Williams relationship soured in 2002 after the 700-pound-thrust EJ-22 engine, a descendant of the V-JET’s FJX-1, suffered repeated flight test failures (see “The Little Engine That Couldn’t,” Feb./Mar. 2005). However, by then Williams already had developed an 80-percent-scale version of its FJ-44 corporate jet engine. The new FJ-33 weighs just 300 pounds and delivers 1,000 to 1,500 pounds of thrust. It incorporates advances pioneered on the FJ-44, including scalloped exhaust pipes that reduce engine noise and widely swept and rounded fan blades, which contribute to lower noise and better fuel economy.

To date, the FJ-33 has been selected to power four VLJ designs seeking FAA certification: Adam A700, ATG Javelin, Diamond D-JET, and Spectrum 33.

Eclipse began looking for a replacement engine in late 2002, and by then, Pratt & Whitney Canada (PWC) was already far along on the development of its PW600 series of 900- to 1,700-pound thrust engines. In 2003, PWC announced its first order, from Cessna, for the 1,350-pound-thrust PW615F, weighing 300 pounds.

The new engines incorporate a host of proprietary technologies including unique fan blade shapes and a high-efficiency compressor, which produces a pressure ratio in two stages that other engines need three or more stages to achieve. PWC also invented a modular construction technique that enables the engine to be assembled faster and serviced easier. For both private pilots and jet taxi businesses, less expensive and faster engine servicing will be an important sales advantage. Modular construction and a new assembly facility in Longueuil, Quebec, helped the company slash the average engine’s production, test, and shipping time from eight days to a mere eight hours. The plant is gearing up to produce as many as 2,000 engines per year.

To date, PWC has contracts to supply engines for Cessna, Embraer, and Eclipse.

And then there’s Honda. GE Honda Aero Engines, located in Cincinnati, Ohio, was formed two years ago to improve Honda’s HF118. With 1,700 pounds of thrust, the little turbofan is competitive with the PWC and Williams engines, but so far the HF118 will power only the HondaJet.

The infusion of oddball ideas or unconventional practices may not produce immediate business success, but it can stir other businesses in an industry to innovate. In the case of VLJs and the aviation industry, the new ideas have come mainly from the computer business.

Several leaders of the very light jet revolution come from the computer or software industries and have brought with them some principles of software development that challenge the aviation industry’s evolutionary tradition. “In the high-tech business, the non-existence of a market and a product for it is viewed as an opportunity,” says Vern Raburn. “It’s like, ‘Cool, no competition.’ In aviation, the non-existence of a market or product is used to say it can’t exist or it shouldn’t exist. Remember the old Bob Dylan lyric, ‘One man’s ceiling is another man’s floor’? Well, that is how I could characterize aviation.”

Raburn’s biggest customer for the Eclipse 500 is Ed Iacobucci, who worked at IBM, then founded Citrix Systems, retired, moved to Florida, and invented DayJet, an air taxi company that depends on “complexity science” for scheduling. Developing the computer models to give customers the flexibility of a taxi service is an undertaking on the order of the manned moon missions, but with the help of the Georgia Institute of Technology and the Santa Fe Institute, Iacobucci has created the system that will make it work.

Raburn has suffered slings from market analysts, who have referred to Eclipse as a “dot.com with wings,” but if he can hold his price—a new Eclipse ordered today would cost $1.6 million—he will be selling a five-seat, twin-engine jet for the same price pilots now pay for a single-engine turboprop with as many as 12 seats. The next-cheaper twin VLJ is Adam’s A700 (with seven seats instead of five), selling for $2.25 million. To hit his price point, Raburn believes he has to change how an airplane is made.

The surprise: After studying composite construction, he chose aluminum. “Composites can’t be scaled,” he says, to meet the company’s mass production model envisioned at 500 aircraft a year. That’s how many Eclipse 500s the company must build (and sell) in order to break even, according to Raburn.

“By the end of next year,” says company spokesman Andrew Broom, “we’ll be able to build three or four airplanes a day. That’s a thousand airplanes a year.”

To build airplanes that quickly, Raburn has

replaced the manual method of riveting pieces together with an automated aluminum construction process known as friction-stir welding. The process was first used on rockets, but never tried extensively on aircraft.

Friction-stir welding was invented and patented in 1991 by the Welding Institute in the United Kingdom. Using specialized tooling, a manufacturer first softens without melting two pieces of metal to be joined. A spindle then stirs the two pieces of aluminum together. The plasticized material is transferred from the front of a pin tool to behind it as the tool traverses along the joint. Because the aluminum never melts, friction-stir welding more closely approximates a forging or extrusion process rather than traditional welding.

Eclipse claims that friction-stir welds are two or three times stronger than single-row riveted joints and that the process is 10 times faster than manual riveting, and four times faster than automated riveting. The company says the process will produce very smooth surfaces, thereby further reducing assembly time by cutting the time required to prepare the aircraft for painting.

“We invested about $30 million” to make the welding process applicable to the Eclipse, says Raburn. The company uses custom-made computer numeric control machines that automatically weld the aircraft structure from the inside out, creating an exterior skin just as smooth as composites, says Raburn. “The great and obvious payoff for us is the speed,” says Raburn. “We can weld an entire set of airplane parts in one shift in eight hours that replaces 1,700- to 1,900-man hours and multiple shifts to build the airplane.”

Another computer whiz bringing software sensibilities to the aviation industry is Adam Aircraft CEO George F. “Rick” Adam. Adam ran the Real-Time Computer Center at the Kennedy Space Center during the Apollo program before taking a string of tech jobs that culminated with the chief information officer slot at finance giant Goldman Sachs. He founded Adam Aircraft in 1998, initially to make new-generation piston aircraft, but in 2003 began development of the $2.25 million A700 very light jet. The company expects to have the A700 certified next year and currently has 310 orders for it.

“I was always struck by how little new technology was making its way into airplanes,” says Adam. “If you bought a general aviation airplane, it looked just like it did 40 years ago. That always struck me as really unnatural.”

Adam has a more modest production plan than Eclipse and still thinks composites are the way to go. Both the A700 and A500 piston aircraft are fashioned from carbon fiber composite, and Adam credits this construction with holding down costs as well as providing a lighter aircraft and a more voluminous cabin. (With composite construction, there is no need for ribs, stringers, or any of the other support structures that hold aluminum fuselages together.)

“It is much less expensive to design and tool an airplane in composites than it is in aluminum,” Adam says. “In aluminum, you have to go to a tool-and-die maker, and the typical turnaround is six to nine months.” (Raburn figures differently: It’s cheaper to tool a composite aircraft, but the material is more expensive than aluminum. Raburn is counting on an automatic production line for further savings.)

“We do all of our own tooling in-house,” says Adam, “and we can build a tool in a week. In software, we used to call this ‘rapid prototyping.’ If we make a mistake, we fix it in a couple of days. If a guy in aluminum tooling makes a mistake, it loops back through months and months and months. Time is money. By cutting down the elapsed time, we use less money.”

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.

Before founding Avidyne in 1994, Schwinn led a global communications equipment manufacturer to achieve annual sales of $150 million before it was acquired by computer chip maker Intel. Avidyne supplies the systems to piston-engine aircraft makers Cirrus, Columbia, and Piper and to VLJ makers Adam, ATG, and Eclipse.

Integrated flight deck systems have proven immensely popular. Garmin, best known for its Global Positioning System receivers, has followed Avidyne into the market.

For Schwinn, the key to keeping integrated displays affordable is the successful application and integration of technologies developed for non-aviation industries, primarily automobiles.

“The aviation market isn’t that big,” says Schwinn. “We had to be good at leveraging technology that was originally designed for another use. So our screens are laptop screens. Our Attitude, Heading, and Reference System uses gyros and accelerometers that were built for car stability systems by the tens of millions.”

Avidyne relies heavily on an automotive high-speed, safety-critical data communications system, called FlexRay, developed by a consortium that includes automakers BMW, DaimlerChrysler, General Motors, and Ford; automotive component maker Robert Bosch; and Motorola and Phillips Semiconducters. In cars, FlexRay drives an increasingly elaborate system of sensors and actuators that control things like anti-lock brakes and automatic stability controls.

Small, efficient fanjet engines, systems that make the aircraft easier to fly, R&D money from NASA, and a small group of entrepreneurs who didn’t know they couldn’t build lightweight, cheaper jets have all come together over the past 15 years to create a resurgence in the U.S. general aviation industry. Orders have been placed for more than 3,500 VLJs, with a total market value of more than $5 billion.

About two-thirds of the orders will form the backbone of a hoped-for air taxi market: a network that could offer on-demand and affordable business travel to the nation’s 5,000 general aviation airports. The air taxi business is targeting middle managers, a market its proponents claim is ignored or ill-served by the airlines. The other one-third of VLJs will go to private pilots.

These 3,500 orders do not include any government sales. On January 30, 2006, the U.S. Department of Defense issued a Request for Information to all very light jet manufacturers, asking them to submit data on the applicability of their aircraft in a variety of roles, from pilot training to surveillance. The Air Force plans to start flight evaluations at Edwards Air Force Base, in California, by December. Another reason that 2006 is the year of the very light jet.

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