- Jun 6, 2006
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'Muppet planes' on drawing board
Enviro-friendly aircraft get look from Boeing
By Dominic Gates
Seattle Times
Tucson, Arizona | Published: 06.06.2006
SEATTLE — When Boeing names an airplane design after a Muppet, it must be pretty different.
Two small teams at the company are re-imagining the airplane in futuristic configurations that sprout wings, tails and engines in unexpected shapes and places.
The research, illustrated in internal documents, aims in two directions: low-cost airplanes, and environment-friendly planes that will be quieter, use much less fuel and leave fewer pollutants in the upper atmosphere.
In the latter category is the "Kermit Kruiser," a low-noise concept airplane with main wings radically swept forward rather than back, and sporting miniature wings on the front.
Then there's the "Fozzie." It has a "Pi-tail" — two vertical tails joined by a piece across the top, and sips fuel because it flies slower using open-rotor jet engines that resemble the old-style propellers.
The concepts are "intended to help us focus technology on a future out beyond the horizon," said Dan Mooney, Boeing vice president of product development, who directs both research teams.
The documents show Boeing has looked at other concepts as well: a supersonic business jet; a megasize freighter; airplanes that use biofuels or hydrogen; and even a "reduced crew" airliner — one with no windows in the cockpit, judging by a sketch in the Boeing documents.
But of all the potential concepts, Boeing has prioritized the "low-cost" and the "green" planes for further research this year. Both teams have begun work with engine companies on the various propulsion alternatives.
The Boeing documents include assessments of very similar research projects that its rival Airbus has sketchily mentioned at scientific conferences.
In an interview, Mooney declined to discuss proprietary details of the designs but offered insight into what his research teams are up to.
He said the latest airplanes being sold today, such as the 787, are designed to meet airlines' projected requirements for about the next two decades. Designers strike a balance among cost, fuel efficiency, capacity, range and other factors based on those projections.
His concept teams, however, think "out beyond 15 or 20 years," where fuel costs, noise or other factors may become more important and reshape what airlines want.
"We need to be developing technology today to allow us to be ready for those uncertainties in the future."
The low-cost team, documents show, is studying the benefits of options such as long, thin wings and new engine types. That team has not yet envisioned new structural designs, however.
In contrast, the Green Team, with a broad mandate to address diverse issues of fuel burn, noise and emissions, has considered some widely differing airplane structures — each with its own whimsical code name. (The Muppet theme may be a reference to the song Kermit sang on "Sesame Street": "It's not easy bein' green.")
● "Kermit Kruiser": Low noise. The engines sit atop a twin-fin tail, so that the noise is reflected upward. The wings are placed so far back they join the fuselage right at the horizontal stabilizer. And most radically, the wings sweep forward, not back, lowering aerodynamic drag and increasing maneuverability at the price of some stability. Keeping this tail-heavy aircraft stable in flight requires a canard — those mini-wings up front. The plane would be a wide-body seating nine abreast.
● "Fozzie": Ultra-low fuel burn. The airplane is designed to cruise at a much reduced speed — 500 mph rather than the typical 600-plus mph of current jets. That would add an hour to the typical transcontinental flight.
Attached to a tail with twin vertical fins and a crossbar (called a Pi-tail because it resembles the Greek letter pi) are engines with an "open rotor" or "unducted fan" design.
The plane has a fanjet gas-turbine engine of the sort used on airliners today, but without the usual duct encasing the fan, Mooney confirmed. At slower speeds, this offers great fuel efficiency.
One internal drawing shows the rotors on the back of the engine; another shows them on the front, the more usual position.
● "Beaker": Low emissions. This airplane has the low fuel burn and same low cruise speed of Fozzie. It has low-emission engines and long, very narrow wings perpendicular to the fuselage. The wingspan is such that the wings must fold to fit an airport gate.
● "Honeydew": Low fuel burn. Another wide-body, this aircraft seems to be a meld of the traditional "tube-and-wing"-shaped airliner and the often-touted "Flying Wing" design that produced the B-2 bomber.
The resulting delta-shaped wing blends in a graceful curve into the fuselage. Yet there is still a distinct fuselage at the front.
The Flying Wing design is more aerodynamically efficient. One disadvantage is that most passengers are far from a window. Honeydew appears to be an intriguing compromise.
Since April, Boeing's Phantom Works research unit, in collaboration with NASA and the U.S. Air Force, has been doing wind-tunnel tests on a small-scale, 21-foot-wingspan prototype of a Flying Wing or Blended Wing Body aircraft concept. Flight testing of the prototype is planned for later this year.
The Air Force is interested in the design's potential as a long-range, high-capacity military aircraft.
So how realistic are these cool-looking airplanes?
"When you look at where energy costs are going in the next decade, it could be time for a change in the rules," said Jerry Ennis, a retired vice president at Boeing's Phantom Works who worked on prototypes.
Like the Detroit carmakers who wheel out fanciful concept cars that never reach the showroom, Boeing may never build an airplane that looks like any of these images.
Still, Mooney said, "Most likely there'll be parts of the technology or parts of the configuration that will find their way onto products of the future."
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This article, while a month old, really surprised me. While these planes were only paper studies, it shows that Boeing is willing to think in an unconventional way when it comes to future aircraft.
As the article says it is highly unlikely that the final product, lets say for instance, the 737 replacement, will look exactly like the aircraft above. However, there is a good chance that some of the technology they propose will be used.
"FOZZIE" is one of the more interesting designs there. The "Pi-Tail", while unconventional and interesting is a bit of a stretch. But besudes the composite structure, FOZZIE is not a new design. With a conventional T-Tail and tail mounted engines you are looking at nothing but a rebirth of the 7J7:
The only problem with the FOZZIE design are the UDF engines. Many have said that they would mean more noise for passengers and on the ground. And since conventional engines are becoming much mroe efficient there really is no need to invest in UDF technology. This is where the ultra-low emission engines of "BEAKER" come into play. Something like this design is much more likely. However, I am unsure about the long, folding wings. Though these are nothing new, they've been used on aircraft carriers since the 40's. Folding wings is a way to fit the new larger aircraft (like a 747 replacement) into the gate.
The thing that strikes me as the most interesting is the position of the engines in all of these designs. It appears that engineers taking part in this study all felt that tail-mounted engines are the most efficient.
For awhile it has been rumored that Boeing is looking into a BWB for its future 747 replacement (Y3) While I like the BWB design, I feel that is to drastic of a change for airlines. I personally feel that something like the "HONEYDEW" design is far more likely for a 747 replacement. It blends the BWB design with more a more conventional A380 type design. It has been said that if sales of the A380 surpass 500 aircraft, Boeing will launch Y3, a 747 replacement.
