Free Republic
Browse · Search
News/Activism
Topics · Post Article

Skip to comments.

Around the World, With 13 Fuel Tanks and a Single Seat
NY Times ^ | November 30, 2004 | MATTHEW L. WALD

Posted on 11/30/2004 10:13:12 AM PST by presidio9

Outsiders look at the GlobalFlyer, a single-seat airplane designed to make the first solo, nonstop, unrefueled flight around the world, and wonder how a pilot could function for 70 hours in a cigar-shaped cabin so snug he cannot even get out of his seat.

But the pilot, Steve Fossett, has another problem in mind: fuel.

Technicians at Scaled Composites, the company that built the plane, like to call it the Flying Fuel Tank. At takeoff - on Jan. 4 or as soon thereafter as the weather permits - it will weigh as much as a 50-seat commuter plane. If it is successful, it will land nearly three days later weighing less than a medium-size S.U.V.

On a recent test flight here it did not so much take off like a jet (which technically it is) as glide into the sky. Fully loaded, it will need more than two miles of runway to lift off.

The GlobalFlyer is first of all a feat of engineering - building a plane strong enough to climb into the sky with so much fuel and efficient enough to fly almost 20,000 miles without refueling. It is also a test of the pilot's skill and of human endurance.

Mr. Fossett, glider pilot, sailor and balloonist, is being sponsored by Virgin Atlantic Airways, whose name is pasted prominently on the ungainly GlobalFlyer. Scaled Composites of Mojave, Calif., also built the Voyager - the two-seat propeller-driven plane that went nonstop and unrefueled around the world in 1986 - and SpaceShipOne, which took home the $10 million X Prize in October for the first private flight into space.

The Voyager, it turned out, was almost too fragile to complete the trip: when the Smithsonian took it apart to get it into the Air and Space Museum on the National Mall in Washington, technicians found cracked flanges in the main spar, the backbone of the wing. (The plane hangs above the information desk at the main entrance to the museum.)

But technology has changed since then. The carbon-fiber and epoxy material is about the same, said Burt Rutan, the company's founder and the planes' designer. But the main spar of GlobalFlyer, which is 110 feet long, is all one piece, built at near room temperature. In the 80's, composites had to be cooked in an autoclave, making such big pieces impossible.

The wingspan is about the same as that of a Boeing 737-900, but there the similarity ends. The oddest part about the GlobalFlyer is what engineers call the "fuel fraction," which is the percentage of takeoff weight that is in the fuel. Lately the GlobalFlyer breaks the fuel fraction record with each new test flight, but on its round-the-world attempt it will be at its most extreme ratio, 82 percent fuel. In contrast, at maximum takeoff weight the 737-900 is 24 percent fuel, with a range of 3,160 miles.

The GlobalFlyer has a system of 13 separate fuel tanks. Managing them is essential to minimizing wing bending and keeping the plane balanced during its metamorphosis from lumbering tanker into featherweight.

A pilot of Mr. Fossett's skill can handle that transition, the engineers say. But he will need more than skill.

While the plane has an autopilot to maintain heading, course and altitude, it still needs work before the flight. No pilot can stay alert for 70 straight hours and, as Mr. Rutan put it, "No one's willing to sleep with the autopilot yet." In a single-seat airplane, sleep is a serious problem.

The Federal Aviation Administration, concerned about a groggy pilot in the last stages of the flight, is considering ordering that the plane take off from Edwards, so that the flight's final hours, with the exception of the last few minutes, will be over uninhabited ocean. But mission planners are leaning toward an old air base in Salina, Kan., with a suitably long runway, so that if the fuel runs out 1,000 miles short of the destination, the GlobalFlyer will be over land.

The plane is supposed to cross the North Atlantic, Europe, the Persian Gulf, India and the Pacific, but the route could be changed during the mission, depending on weather forecasts. The cruising altitude is above most of the weather, but not all of it. And to save fuel, the climb to cruise will be a leisurely 12 hours; descent will also be slow.

But time aloft is so long, and the cruising altitude so high, that the designers switched from ordinary jet fuel to a mixture that is less prone to freezing.

For Mr. Rutan, the GlobalFlyer is an audacious attempt to one-up the Voyager, another of his creations, which his brother Dick flew, with another pilot, Jeana Yeager. That was about 72 percent fuel at takeoff.

Under rules laid out by the international federation that keeps aeronautical records, "round the world" means at least the distance around the Tropic of Capricorn. The plan for GlobalFlyer is 19,864 nautical miles, or 22,859 statute miles. The Voyager did 24,900, which is just short of the distance around the Equator.

This time the plane will use a single jet engine, the same type used as half the power plant for corporate jets. The engine will run during most of the flight well below its ordinary cruise setting, the designers say. Mr. Rutan says jets are so reliable that "it's safer to fly over a long ocean with one turbo-fan than two piston engines."

If it quits at 45,000 feet, or about 9 miles, finding a landing spot is probably not a problem, because it can glide about 30 feet for each one foot loss in altitude, giving it a range of nearly 300 miles before the pilot would have to land, ditch or bail out. But the GlobalFlyer is such a wonderful glider that it would be a challenge to descend fast enough to find breathable air.

The reason is that to maximize its cruise efficiency, and maintain a "clean" wing with as little drag as possible, it has no spoilers, the wing-top devices that are used to reduce lift when the plane has to land. It also lacks flaps, the devices at the rear of the wing that extend to provide extra lift at takeoff.

And to save weight, the Flyer lacks most of the safety devices common to modern planes. It has no deicing system for the wings or windows. It has no radar to spot weather or other traffic. It barely has brakes; engineers removed a rotor from each disc brake.

"In order to build a plane light, you have to build it with very little safety margin," said John Krueger, a mechanic and composite fabricator, standing amid the yucca bushes and jack rabbit tracks at the edge of the 15,000-foot runway at Edwards Air Force Base, watching the liftoff of a test flight on Nov. 17. "When it's this heavy, the margin is very small," he said.

Even the emergency oxygen supply may be too small to keep the pilot alive if the cabin depressurizes at cruise altitude. A bigger system would weigh 12 pounds more, and Mr. Fossett, 60, said he was not sure that it was worth the weight. "A friend of mine suggested I go on a diet," he said. (He put his weight at 213 pounds.)

The Flyer looks like two planes flying in close formation. Mr. Rutan designed it with two huge booms, each with a tail at the back; the huge wing; and a small fuselage in the middle.

It is almost a single-use airplane, although Mr. Fossett said he might fly it again after a round-the-world trip. While new airliners use increasing amounts of composite materials, aviation experts say that the Flyer probably does not advance the technology they use. It could break new ground that would be useful for other kinds of planes, though, including high-altitude drones sent aloft for long periods, for communications, surveillance or other purposes.

Mr. Fossett, interviewed by telephone from South America, where he was seeking to set new records in gliders, said he looked on the trip mainly as a piloting challenge. He said the autopilot was coming along as Jon M. Karkow, the project engineer and main test pilot, got more experience with the plane, but added, "If I'm having trouble with the autopilot, then I will absolutely not fall asleep."

Scaled and Virgin refused to discuss the cost of the mission.

"I wonder if the Smithsonian will take it," said one Scaled technician, Clint Nichols, watching it take off. Then he added, "It's weird enough."


TOPICS: Culture/Society; Extended News
KEYWORDS: oopsicrappedmypants
Navigation: use the links below to view more comments.
first previous 1-2021-4041-60 last
To: concordKIWI

BTTT


41 posted on 11/30/2004 2:02:48 PM PST by shaggy eel
[ Post Reply | Private Reply | To 40 | View Replies]

To: shaggy eel

Old Fossett doesn't have to worry about collecting any moss on his private parts. :)


42 posted on 11/30/2004 2:22:17 PM PST by blackie (Be Well~Be Armed~Be Safe~Molon Labe!)
[ Post Reply | Private Reply | To 39 | View Replies]

To: blackie

,,, he doesn't seem to have any funding problems either.


43 posted on 11/30/2004 2:25:06 PM PST by shaggy eel
[ Post Reply | Private Reply | To 42 | View Replies]

To: shaggy eel

More power to him!


44 posted on 11/30/2004 2:46:21 PM PST by blackie (Be Well~Be Armed~Be Safe~Molon Labe!)
[ Post Reply | Private Reply | To 43 | View Replies]

To: avg_freeper

There are several problems with your numbers which make the amount of additional fuel required much less than an order of magnitude.

The biggest problem is in your choice of the circumference of the earth as the required distance. None of the "around the world" flights have taken place over the equator. In fact most of them have taken place mostly north of 30 degrees. So the actual flight distance will be substantially less than ~24000 mi, probably more like 16 to 18000 miles.

Second, the range you state for a 747 includes a significant amount of fuel reserves per FAA mandates to allow for diversions and wind conditions. Since any "around the world" attempt would be flown from west to east and using the jet stream as much as possible and since this would be an experimental flight, not a passenger flight, no fuel reserves would be required.

Yes, GW would affect the range, but at the end of flight you'll be much lighter than a regular, empty 747, so you'll regain some of that loss. Also, you'd be flying at the maximum altitude that you can reach for the entire flight and at the minimum airspeed (this is another thing that the standard range numbers do not include since it would never be done on a passenger flight due to safety concerns).

Add to that the fact that you would run the engines as lean possible since you wouldn't care about reducing their lifespan (yet another thing not included in the standard range number).

Also, anyone who was serious about attempting this, would go over the airframe and clean it up as much as possible, so it would have significantly less parasitic drag than the average 747.

Add all this up and I think the numbers would be closer to 3 times more gas rather than 10 times. Still a hell of a lot of extra gas and it might not be possible. But I think its a heck of lot closer than you think.


45 posted on 12/01/2004 1:19:53 PM PST by RatSlayer
[ Post Reply | Private Reply | To 38 | View Replies]

To: RatSlayer
It was an rough order of magnitude estimate and I've gotten to be pretty conservative by occupation. You have some good points though.

Fuel burn during ascent would be a killer at this higher GW / trim attitude. A diminishing problem as you indicated but bad none the less.

I don't believe there is that high of a knockdown in fuel consumption for jet engines due to durability issues. I don't even see that in turboprops.

But like I said you present a compelling case.

46 posted on 12/01/2004 1:50:39 PM PST by avg_freeper (Gunga galunga. Gunga, gunga galunga)
[ Post Reply | Private Reply | To 45 | View Replies]

To: avg_freeper; RatSlayer
In addition, my less condescending/smart-a$$ tone is probably an improvement over my last post.
47 posted on 12/01/2004 1:56:43 PM PST by avg_freeper (Gunga galunga. Gunga, gunga galunga)
[ Post Reply | Private Reply | To 46 | View Replies]

To: presidio9; fourdeuce82d; El Gato; JudyB1938; Ernest_at_the_Beach; Robert A. Cook, PE; lepton; ...

FReepmail me if you want on or off my health and science ping list.

48 posted on 12/01/2004 9:09:06 PM PST by neverdem (May you be in heaven a half hour before the devil knows that you're dead.)
[ Post Reply | Private Reply | To 1 | View Replies]

To: jordan8
Recently I read an article on sleep that talked about a drug that keeps you awake without the speed-like side effects.

Modafinal. It is prescribed for narcolepsy. Gulf War I pilots used it. Modafinal is a controlled substance, but it predecessor, Adrafinal is not. Adrafinal requires liver enzyme monitoring if used regularly. You can read more here if curious.

49 posted on 12/02/2004 12:55:59 AM PST by bluefish (Holding out for worthy tagline...)
[ Post Reply | Private Reply | To 25 | View Replies]

To: LibertarianInExile

50 posted on 12/02/2004 1:50:01 AM PST by .44 Special (Death to Traitors!)
[ Post Reply | Private Reply | To 34 | View Replies]

To: avg_freeper

As you said, I think the GW problem is the biggest issue.

The fuel burn during climb out would definately be brutal. And it would probably need a couple of JATO bottles and using Groom Lake in winter to get off the ground.

I suspect it would also need some kind of dolly, which would fall off at take off, because I doubt the landing gear would support that much weight (or the rolling resistance would be way to high at that weight).

I did find some other specs for the 747-400ER, which also improved on your numbers, but it wasn't clear to me under what conditions those numbers were valid, so I didn't quibble with your numbers. For instance, I found a specs on the Boeing website of over 7000 nautical miles, a cargo weight of just under 200,000 lbs with a gross weight of almost 1,000,000 lbs for the 747-400ER.

So a 747-400ER can do almost 8000 statute miles and the cargo weight is about twice your estimate, so I'm getting close, but I'd still have to load it well above spec.


51 posted on 12/02/2004 10:31:25 AM PST by RatSlayer
[ Post Reply | Private Reply | To 47 | View Replies]

To: avg_freeper

Heh, I think I might need to change over to an A340-500.

I was just reading Aviation Week and an ad for Airbus said that an A340-500 has made a 9000nm commercial flight from Singapore to NYC flying east to west.

So a commercial flight, chasing the earth's rotation and probably having to fly at crummy altitudes in order to avoid the jet stream, managed to do a 10,000 statute mile flight. I wonder how much fuel he had in reserve.

Actually, I think the 747-400er would probably still be the better choice, because it probably has a higher max GW and max thrust.


52 posted on 12/02/2004 2:47:57 PM PST by RatSlayer
[ Post Reply | Private Reply | To 46 | View Replies]

To: RatSlayer
At the risk of being a spoil sport, it seems to me that it would be pretty easy to do a solo, around the world, unrefueled flight by taking a 747, stripping out all the seats and adding additional fuel tanks in the cargo hold and the passenger compartment.

I will venture to guess that Rutan's designing/building/test flying of this plane costs magnitudes less money than buying a 747 and then installing tanks and modifying it. Sure, a billionaire is funding the flight but there's no fun in using a 747.

Sorry for the late response...I've been offline for a week and just saw this thread.

53 posted on 12/06/2004 10:09:46 AM PST by hattend (Where'd my tagline go?)
[ Post Reply | Private Reply | To 17 | View Replies]

To: neverdem

That part of the trip over Egypt, Saudi Arabia, S. Iran and S. Afghanistan, Pakistan and India would help keep me awake...to be sure.


54 posted on 12/06/2004 10:14:18 AM PST by hattend (Where'd my tagline go?)
[ Post Reply | Private Reply | To 48 | View Replies]

To: RatSlayer

Your fuel calcs also don't take into account shutting down two engines once you get to cruising altitudes. Navy ASW pilots do it all the time in a P-3 Orion.

Just a thought ;-)


55 posted on 12/06/2004 10:17:30 AM PST by hattend (Where'd my tagline go?)
[ Post Reply | Private Reply | To 52 | View Replies]

To: hattend

RE: "Your fuel calcs also don't take into account shutting down two engines once you get to cruising altitudes. Navy ASW pilots do it all the time in a P-3 Orion. "

Actually, I thought of that. But I'm guessing that for at least the first half of flight you'd probably need the thrust from all four engines to lift the huge amount of weight to as high an altitude as possible (for both the reduced drag and to get into the jet stream).

Since it would probably only affect the last half or quarter of the flight, I didn't bother to mention it (also the post was getting pretty long without it).


56 posted on 12/06/2004 10:27:32 AM PST by RatSlayer
[ Post Reply | Private Reply | To 55 | View Replies]

To: hattend

RE: "I will venture to guess that Rutan's designing/building/test flying of this plane costs magnitudes less money than buying a 747 and then installing tanks and modifying it. Sure, a billionaire is funding the flight but there's no fun in using a 747."


Yeah those are good points and Rutan's forte is his ability to do minimalist designs. Like I said in my original post, I was probably being a spoil sport.

But, if I was the pilot, I'd sure feel a lot safer in a 747 that could do the trip in under 40 hours rather than Rutan's design which will take 70 hours and who's airspeed will need to be carefully monitored (the wing design he uses is very efficient, but the penalty is that the cruise speed is very close to the stall speed).


57 posted on 12/06/2004 10:37:24 AM PST by RatSlayer
[ Post Reply | Private Reply | To 53 | View Replies]

To: RatSlayer

"since this would be an experimental flight, not a passenger flight, no fuel reserves would be required."

It would be an IFR flight and the fuel reserves would be required.

You must not be a pilot.


58 posted on 12/06/2004 10:37:26 AM PST by dalereed
[ Post Reply | Private Reply | To 45 | View Replies]

To: RatSlayer

Youo can't fly a 747 single pilot either.

It's illegal!


59 posted on 12/06/2004 10:40:26 AM PST by dalereed
[ Post Reply | Private Reply | To 57 | View Replies]

To: presidio9

There I was just minding my own business searching for a particular John Kerry article. I typed in one of the keywords I had given it and to my absolute surprise (and delight!), I found that mine wasn't the only "OOPSICRAPPEDMYPANTS" article!!! I am just crying with laughter! I love this sketch and haven't seen it in ages. Thanks for making my morning! And two years ago, at that!


60 posted on 11/04/2006 4:30:35 AM PST by TXBlair (Delightfully tacky since 1974)
[ Post Reply | Private Reply | To 8 | View Replies]


Navigation: use the links below to view more comments.
first previous 1-2021-4041-60 last

Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.

Free Republic
Browse · Search
News/Activism
Topics · Post Article

FreeRepublic, LLC, PO BOX 9771, FRESNO, CA 93794
FreeRepublic.com is powered by software copyright 2000-2008 John Robinson