Eclipse 500 Gets Provisional Type Certificate

The FAA will issue the full TC on 30 August.

Enboarding with Help from Einstein

The current issue of New Scientist has a story on of how Einstein's theory of relativity can be applied to the problem of how do you get all those people onto that airliner in that amount of time. Einstein's theory coupled with a fair amount of modeling and simulation (CS 350) activity, that is.

Enter Eitan Bachmat and his colleagues at Ben-Gurion University of the Negev in Israel. Bachmat wasn't initially aiming to solve the problem of "enplaning", as airlines rather grandly call it. He was studying the performance of digital storage systems such as PC hard drives, looking at how to read and write data most efficiently. Say you send your hard drive a big bunch of read/write requests. What you want to know is the quickest way to carry out those tasks. How do you find the fewest drive rotations needed to do the job?

One day a colleague who saw this work said, "Hey, that looks a lot like airplane boarding," and so Bachmat and his colleagues decided to explore this parallel route. "We thought we could do this and take stuff back to the hard drive problem," he says.

[...]

Fortunately, physics has something to say about problems like this. Odd as it may seem, it occurred to Bachmat and his colleagues that the way passengers fill up a plane looks like relativity's description of how things move through the four dimensions of space-time under the influence of gravity.

According to relativity, an object in "freefall" follows the trajectory that ages it the most. Throw a stone into the air: it will trace out an arc and return to the ground. Attach a stopwatch to the stone and you would see that, out of all the trajectories through space-time the stone might have taken under the influence of gravity, the arc of its flight is the one in which the most time passes. In other words, the stone maximises the amount of time (in its own reference frame) that passes as it flies up and then falls back to Earth.

[...]

Bachmat and his colleagues chose their metric so that the past-future relationship between passenger "space-time" points is precisely the same as the blocking relationship on a real aircraft: in passenger "space-time", if someone is blocking you, they are in your future.

"You can determine whether passengers are in each other's future or past"
Having called their virtual passengers to this mathematical boarding gate, Bachmat and his colleagues can calculate the overall boarding time by finding the equivalent of a free-fall trajectory through that passenger "space-time". The maths [sic -- damned Brits] isn't simple but it gives you formulae for calculating boarding time under different boarding policies. Crucially, it also lets you see the effect of varying parameters such as legroom and luggage-stowing time (Journal of Physics A, DOI: 10.1088/0305-4470/39/29/L01).

So what did they discover? "What turns out to be critical is the notion of congestion," says Bachmat. The team incorporated this into their model as a variable k, which depends on legroom, passenger width and number of people per row. "It tells you how crammed passengers are."

The team found that policies that work well for small k - the rarefied world of first class - become terrible for the high-k crush back in economy. Where congestion is low, furthest-row-first works well, but this becomes progressively worse as congestion increases. The people destined for seats 68A and 68B, for example, could be standing alongside row 67, waiting for the woman in 68C to stuff her bag into the overhead locker. While they wait, they block the people heading for row 67 from reaching their locker, and so on. So even with a furthest-row-first policy, high congestion means that the queue will be all the way out of the plane door within minutes, with not one other person able to get to their own row.

For really high congestion, random boarding soon becomes the better option. For the moderate-squeeze conditions that are the reality for most of us, the best balance is a high level of row randomness combined with a touch of back-to-front.

"For moderate-squeeze conditions the best balance is a high level of row randomness combined with a touch of back-to-front"

[...]

What also emerged is that boarding time is proportional to the square root of the number of passengers. Considering how complex things become as the numbers increase, that's actually not bad, but it still has significant implications for today's ever-bigger airplanes, like Airbus's 555-seat superjumbo, the A380.

There's more: Window seats in the back first helps. Who'd've thunk it?!

The online version of the article itself remains in a subscriber-only zone for a while, but it's in the current print edition.

(Hat tip to Todd S.)

Small Biz Jets in the News

There are two stories in today's New York Times on small business jets.

The first is that Honda announced yesterday at Oshkosh that it's going to build its 6-passenger jet.

The twin-engine, 6-passenger HondaJet will go on sale by 2010. It will be built in the United States, at a yet-to-be-determined location. Honda, which announced the jet at an air show in Oshkosh, Wis., said it would begin taking orders this fall.

To market the jet, Honda will form an alliance with Piper Aircraft, the 69-year-old manufacturer of a line of small planes starting with the Piper Cub, a pioneer in general aviation aircraft.

[...]

Honda officials estimated that the very light jet market would total about 200 planes a year and said it hoped it could capture a good chunk of those sales by stressing the plane’s unique features.

The HondaJet’s engines will be mounted over the wings, not over the tail as on many private jets. The plane will also make extensive use of composite materials instead of aluminum, which will make it lighter and permit it to use less fuel.

The HondaJet is expected to be 5 percent more efficient at cruising speed, said Michimasa Fujino, a vice president of Honda Research and Development Americas, who has led the jet’s development.

The second story is on the air taxi business model in which companies sell seats on planes like the forthcoming Eclipse 500 to get business travelers to and from quicker and more directly than by using the big carriers, but at a price premium.

For years, questions about the size of an air taxi market have been largely theoretical. But that will change this year, as Eclipse Aviation of Albuquerque begins building the Eclipse 500, a six-seat plane. The company expects the plane will receive its long-awaited certification from the Federal Aviation Administration as soon as this week.

With the Eclipse, two start-up airlines, Linear Air and DayJet, say they can ferry business travelers to hard-to-reach outposts with fewer frustrations — and get them home in time for dinner with their families.

“One of the first things they teach you in sales is to look for the pain,” said William E. Herp, chief executive of Linear Air, an air charter company that has ordered 30 Eclipse planes at a total cost of $50 million. “And there is a lot of pain out there among business travelers who are flying on commercial jets.”

[...]

The 33-foot Eclipse plane, which will cost $1.5 million, can carry two pilots and four passengers and fly at speeds of over 400 miles an hour. By comparison, a twin-engine Cessna CJ-1, a jet that also carries four passengers, costs about $4.3 million and can fly 448 miles an hour. Categorized as a very light jet at less than 10,000 pounds, the Eclipse offers comfort more akin to flying in a leather-appointed sport utility vehicle than a bigger corporate jet with a wet bar. There is also no bathroom — a fact that has caused some aviation industry veterans to pass up the plane for an air taxi service.

“The absence of a lavatory is going to be a problem,” said Robert L. Crandall, the retired chairman of American Airlines who is now chief executive of Pogo Jet, a start-up airline looking to get into the air taxi business in the Northeast.

[...]

Among the first to put the Eclipse into service will be Linear Air, founded in 2004 by Mr. Herp, an entrepreneur. His airline started as a charter service, flying wealthy travelers to Martha’s Vineyard from Boston and New York in Cessna turboprop planes. The company now also markets its services to small teams from consulting firms and other businesses who need to travel together to see clients or visit remote offices or factories. Because of the Eclipse’s faster speed, Mr. Herp said it made sense for him to expand his airline to Washington, Los Angeles and San Francisco.

“Eclipse is the game in town right now,” said Mr. Herp, speaking from the Albuquerque airport last week after visiting Eclipse’s production plant, where the company is assembling the first 10 Eclipse 500’s. Mr. Herp was enthusiastic about how Eclipse’s production was automated, unlike the more time-consuming construction methods used to make other private jets, and about how Eclipse, for the moment, had three production shifts running around the clock, seven days a week.

Both stories require registration or some workaround.

Dodging (Silver) Bullets

In this article at ACM Queue, Alex Bell, a software architect at Boeing, pans the latest palatives in software development -- XML, UML, etc. -- and recommends what might be called reality-based software construction:

The challenges of software development are difficult enough without also having to endure the ricochet of silver bullets strafing supporting organizations. For example, many systems engineers have discovered that using the UML greatly simplifies the efforts that their predecessors unnecessarily struggled with in pre-UML days. As opposed to having to devote significant efforts to the consideration of constraints such as network bandwidth, processor speeds, and the speed of light when developing system architectures, such annoyances are now overcome by creating reams of UML diagrams containing very vague entities and equally vague navigation between them. Unfortunately for software engineers, the UML silver bullets whizzing through the systems engineering space translate into much more work for them.

[...]

It is ironic that a reverence for silver bullets usually brings more pain to software organizations than if they had simply rolled up their sleeves, focused on traditional engineering activities, and accepted that there is no such thing as a free lunch. Postponement of effort, production of useless artifacts, and illusion of progress are just a few of the factors that result in big price tags when reality eventually trumps denial. Even in the absence of Fred Brooks's well-known admonitions [there are no silver bullets that solve everything], it is startling that the failure of past silver bullets to hit their targets is not enough to make us very wary of them today.

Link via Slashdot, where comments will, with near certainty, turn into one or more flame wars.

Lockheed Martin "Polecat"

A little late on this -- just getting this blog resurrected here -- but check this out:



It's the high-altitude almost-all-composite no-tail Lockheed Martin "Polecat" UAV. (Click the image for the full-resolution version.)

With a 90-foot wingspan and a tailless design, the "Polecat" UAV looks like a smaller version of the B-2 stealth bomber. And like the B-2, the drone has been built to be stealthy and sneaky. But the twin-engine Polecat is "90 percent composite materials, rather than metal," the L.A. Daily News notes. "The vehicle is also made from less than 200 parts," adds Aviation Week. "Adhesives are used rather than rivets, decreasing the amount of labor needed to construct it -- that approach also contributed to a lower radar cross section inherent in the design."

The Polecat has taken two subsonic flights, around 15,000 ft. But, eventually, the idea is to fly it 60,000 and higher -- and break the sound barrier. Up there, contrails don't form, Jane's observes, so the plane can stay hidden even better. Plus, Lockheed wants to see how its composites hold up at high altitudes.

Text from Defense Tech. Also, check out the following from New Scientist:

The Skunk Works thinks a technique called 3D rapid prototyping, or "3D printing", is the best way to lower costs.

In rapid prototyping, a three-dimensional design for a part - a wing strut, say - is fed from a computer-aided design (CAD) system to a microwave-oven-sized chamber dubbed a 3D printer. Inside the chamber, a computer steers two finely focussed, powerful laser beams at a polymer or metal powder, sintering it and fusing it layer by layer to form complex, solid 3D shapes.

The technique is widely used in industry to make prototype parts - to see if, for instance, they are the right shape and thickness for the job in hand. Now the strength of parts printed this way has improved so much that they can be used as working components.

About 90 per cent of Polecat is made of composite materials with much of that material made by rapid prototyping.

Electronic Flight Document Reader

At EAA/Oshkosh, ARINC introduced the eFlyBook, an electronic paper document viewer for general aviation info.

Electronic paper is a non-glare white plastic screen that displays electronic documents just as if they were printed on traditional paper. A user can also "write" on the screen with a stylus just like regular paper. The handwriting can be captured electronically, stored and erased, and the screen can be used again and again.

The iRex iLiad has a high-resolution black and white display that closely matches the appearance of printed paper. The glare-free white surface incorporates iRex's high-brightness electrophoretic display technology which remains as clear and readable as paper under all conditions, including direct sunlight.

Under the marketing agreement, ARINC becomes the exclusive distributor for iRex's electronic paper based eReader system in the aviation market. ARINC's first product using the new technology is ARINC eFlyBook™, a self-powered portable flight document library intended for use by U.S. based general aviation pilots. It stores hundreds of FAA charts and essential documents in memory and displays them with high legibility on the electronic paper screen.

This is a version of the iRex iLiad eBook reader.

Link via Engadget.

Battery Powered Plane

From the Cellar Image of the Day, it's the world's first battery powered flight. 160 AA batteries in a 20 series, 8 parallel format. (EGR 101 students: What's the available power?)



CNET Asia story here.