Today the Boeing 787 "Dreamliner", said to be 20 percent more efficient, 60 percent quieter, and significantly cheaper to maintain, passed a huge milestone as it finally took off and landed.

Watching the televised takeoff of the 787--after two years of delays brought on by manufacturing errors and structural problems--brought back some memories. Six years ago I visited Boeing's rain-drenched tarmacs and vast hangars in Everett, WA, to report a feature for Technology Review on the then-new project to build what was dubbed the "7E7" commercial jet.

The idea was to gain an edge on Airbus by offering a midsized super-fuel-efficient jet, with better jet engines, and reduced weight enabled by far wider use of composite structural materials as well as fewer bulky pneumatic control systems.

In 2003 Boeing engineers and executives spoke excitedly about how the 7E7 would take collaborative Internet-enabled design and widely distributed manufacturing processes to new heights. Designers around the world would collaborate on the same master file over the Internet. Then subcontractors around the country and world would get a copy of those files, whip together big chunks of the structure, and ship those chunks back to Everett. Boeing would simply snap together the parts. No problem. "We call it our Lego airplane," Frank Statkus, Boeing's vice president of technology and processes, joked to me at the time.

The improved computer design process was meant to eliminate problems. Previously, Statkus explained, a supplier would sometimes "have to digitize our picture to tell his machine how to build it. This translation sometimes caused errors."

Well, of course, Boeing didn't squeeze out all the errors. Production was hampered by ill-fitting parts and structural problems that led to five delays, extending the commercial delivery date two years (it's now scheduled for late 2010). In 2008, for example, the company found that parts of the center wing box--the massive structure at the center of the plane, extending to two-thirds of the wingspan--required stiffening with new brackets, which in turn forced the re-routing of some wiring. The component--15 meters long and 5 meters wide--had been designed and built by Boeing, Mitsubishi Heavy Industries and Fuji Heavy Industries, in Japan. And, earlier this year, Boeing also had to resolve another structural issue.

Back in 2003, Mark Jenks, Boeing's director of technology integration told me that the plane was "the future. It really is. It's a huge deal for us. If we get it wrong, it's the end. And everyone here knows that."

After today's historic flight, and with orders for 840 planes already taken, the hard part may finally be done.

Carbon nanoparticles fed to fruit fly larvae don't appear to harm them but remain in their tissues into adulthood. The fly on the right is a control; the one in the middle was fed carbon black while a larva; and the fly on the left was fed multi-walled carbon nanotubes while a larva. Credit: Brown University

A series of experiments in fruit flies suggests that different forms of carbon, though nearly chemically identical, have very different toxicities in fruit flies. Two of the materials caused physical impairment and mortality: carbon black, which is found in automobile tires and in an "activated" form in electrodes and filtration systems; and single-walled nanotubes, which are being explored for many electronics applications and are already used in composite materials.

Researchers at Brown University in Providence, RI exposed fruit-fly larvae and adults to four forms of carbon in their food and on their bodies. These included single-walled and multi-walled nanotubes, buckyballs, and carbon black. These materials are all based on meshes of carbon atoms in various forms. Nanotubes are rolled up sheets of carbon mesh in single or multiple layers; buckyballs are hollow spheres of the same mesh; and carbon black is made up of particles of elemental carbon.

The larvae could eat all four with no apparent adverse effects, though they did retain the particles in their tissues into adulthood. The researchers speculate that this could mean nanomaterials could accumulate and get passed up the food chain, just as DDT does.

In adult fruit flies, though, different forms of carbon had different effects. Adult fruit flies were dropped into test tubes containing the materials and observed as they made their way out or not. Buckyballs and multi-walled nanotubes didn't seem to harm the flies, but carbon black and single-walled nanotubes maimed and killed them. And the multi-walled nanotubes could be carried on the flies' bodies from one test tube to another just as other insects carry pollen, suggesting that they might act as vectors. The results were published online in the journal Environmental Science & Technology.

The Brown researchers will now try to determine the mechanism of the nanomaterials' effects, and will test other common nanomaterials including nanosilver. They suspect that the toxicity of some forms of carbon is related to the particulate nature of the materials. Dust in a coal mine harms the lungs not primarily because it contains toxins but because of the physical effects of the particles; something similar might be happening to the flies. So, are the fruit flies are the canaries in the nano coal mine? It's too early to say because what the results mean for humans is not clear. However, other researchers have previously reported that multi-walled nanotubes have the same carcinogenic effects as asbestos in the lungs of mice.

Credit: Boeing

It's not easy being a green airliner. The 787 Dreamliner--Boeing's midsize, fuel-efficient passenger jet--is being delayed again.

The maiden flight of the 787--already two years overdue--was to take place on June 30, but today Boeing announced an indefinite delay to add more structural reinforcements.

"Consideration was given to a temporary solution that would allow us to fly as scheduled, but we ultimately concluded that the right thing was to develop, design, test and incorporate a permanent modification to the localized area requiring reinforcement," Scott Carson, president and CEO of Boeing's commercial-airplanes division, explained in a statement. "Structural modifications like these are not uncommon in the development of new airplanes, and this is not an issue related to our choice of materials or the assembly and installation work of our team."

Carson's mention of materials is important. The 787 is the first commercial aircraft in which major structural parts are made of composites rather than aluminum alloys. The difference slashes weight and helps boost the fuel efficiency of the plane by 20 percent. Back in 2003, we reported on this pioneering effort in commercial aviation.

Composite materials are notoriously difficult to model. Their fiber layers are oriented in different directions, and each layer is made of many individual fibers that vary somewhat in thickness. Such complex materials are far harder to precisely re-create in computer models, compared to monolithic chunks of aluminum. And Boeing has encountered trouble with 787 composites before. As we reported last spring, the company said that parts of the 787's composite-made wing box--the major structural piece inside each wing, measuring more than 15 meters by 5 meters and weighing 55,000 pounds--had buckled in stress tests. To fix that problem, Boeing added new pieces and brackets and rerouted wiring to accommodate the retrofits.

The new schedule for the first flight--and the first delivery of some of the 865 787s that have been ordered by airlines--will not be available for several weeks, the company said.