On the Record With
Oliver Masefield, Vice President Engineerng, Eclipse Aviation

"My time's been cut out doing other things," remarks Oliver Masefield, vice president of engineering for Eclipse Aviation, "and I haven't had much time to listen to people bad-mouthing our product." Nevertheless, in an interview with Show News, Masefield explained how the Eclipse 500 squeezes six seats, a 41,000-foot cabin and a 1,600-mile range into approximately the same empty mass (2,700 pounds) as a Honda Accord, a feat that some of the company's competitors have openly dismissed as impossible.

"I'm a fanatic about weight," says Masefield. Many aircraft get into an upward weight spiral during development, he says, but the Eclipse 500 is different. "When I joined the program and had a discussion with Sam Williams, and he explained what the engine was capable of doing, it was very apparent that it had tremendous capability." Light in weight and very efficient, the EJ22 engine launched the Eclipse on a downward weight spiral, where less weight led to less wing area, and less weight again.

"The weight of the engine is a key item, but we had to be very, very careful not to mess up on the other systems," says Masefield. Some items -- from seats to oxygen bottles -- do not scale down as the airplane gets smaller; as a result, smaller airplanes tend to have higher empty weight fractions than larger aircraft.

"We front-loaded the development and spent more money early on, which allowed us to do more optimization for minimum weight and cost." Masefield's view is that "the first solution is not good enough." Using computer-aided engineering tools -- "in the cheap phase" -- every aspect of the Eclipse design was revised several times and optimized for low weight and low cost.

Another important factor: "The whole aircraft is a point design," says Masefield. "We eliminated the temptation to build in weight for a growth version. We can't afford that."

To save weight, the fuselage is not cylindrical: Passengers and crew enter at the widest point and move forward and back into a tapering cabin. Internally, the structure has direct, simple loadpaths; the rear wing spar, for example, is co-located with the rear pressure bulkhead.

Masefield credits new metalworking technologies -- "I don't like composites in primary structure" -- with eliminating weight from the Eclipse. Ribs and bulkheads are produced by high-speed machining. "You can get down to very thin wall thicknesses and put the weight where you need it. If you have a hydro-formed rib, one part dictates the thickness and you carry that on the remainder of the rib."

Friction-stir joining replaces 60 percent of the rivets in the Eclipse airframe, saving weight. "It's the best of many worlds," says Masefield. "It's highly automated. The operator prepares one set of parts while the other is in the machine. It has low scrap weights and light weight."

Computer-aided design iteration simplified the systems. "Leave something out," says Masefield, "and it doesn't weigh anything or cost anything." The only hydraulic systems on the Eclipse are the brakes; the flight controls are manual and the flaps, speedbrakes and landing gear are electrical.
Critics have suggested that the tiny EJ22s will breathe hard trying to provide climb power while pressurizing the cabin. "Any jet doesn't like bleed," says Masefield. "We've gone away from trying to have heated leading edges, either by electrically or by bleed air" -- the Eclipse has rubber-boot deicing -- "and we've worked on good sealing for the cabin." All performance calculations assume that all air-bleed needs are being met.

The Avio integrated avionics system saves weight by replacing almost 30 separate boxes with four chassis units. Developed by Eclipse in association with Avidyne, BAE Systems, General Dynamics and other partners, Avio reflects a different development philosophy from other avionics systems, says Masefield. Avionics suppliers design boxes and systems to work on a variety of aircraft, but Avio "is optimized for our aircraft. We invested heavily in its development and we're not really interested in whether the components are sold for other aircraft."

Masefield's biggest challenge: putting the development team together. "We have been able to attract the best and the brightest, but it has taken time to do that -- it took us nine to 12 months, versus three to six months. But we have had strong budgets, and we've been able to do things the right way the first time -- not only compared to any start-up, but to the rest of the industry."

By Bill Sweetman