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Ari707
2007-10-10, 04:33 PM
this may be a simple question but I was just on theBoeing web site looking at 747-400 details and noticed that the 747-400F has a much shorter range then a pax 747-400 they both carry the same 57,285 gal. of fuel and have the same max takeoff weight of 875,000 lbs, so why the shorter range?

T-Bird76
2007-10-10, 05:46 PM
Cargo cans take up far more volume and weigh more then passengers even when fully loaded.

lijk604
2007-10-10, 05:53 PM
Cargo cans take up far more volume and weigh more then passengers even when fully loaded.

Just to add to that...
Typical full B747-400...420 pax @ 225 lbs/pax (includes bags) = 94,500

A full cargo B747-400...can typically carry 250,000-300,000 pounds.

hiss srq
2007-10-10, 07:58 PM
Payload. Density altitude, engines, payload and fuel combined. It all plays in on that. If you have a 747-400F with tanks full because you need the range and only have say 8,500 feet of runway your going to probably run into issues on a 95 degree day. Payload restrictions. Would you beleive on that note A-320's and A-319's have to be load restricted for that same reason out of airports likme Philly and Charlotte on a regular basis. It is a little complicated to explain but temp. and runway length has a lot to do with what a plane can or cannot take and how it will perform in a given condition.

PhilDernerJr
2007-10-10, 08:29 PM
All the answers were right, but Max Takeoff Weight doesn't have so much to do with range, only the weight that the aircraft's structure can handle on takeoff. Once it's in the air, it's ability to MOVE is another story.

Though both might have the same MTOW, that does not mean that they can reach their max range at that weight.

However, I honestly would have thought that an empty 744F, since it has a smaller upper deck and no seats or galleys, would have more range than an empty pax 744.

N790SW
2007-10-10, 10:19 PM
Can someone answer why temp effects the plane on takeoff? because I did notice onetime when I was flying it them summer it was ALOT faster then it would be when I flew on a 29 degree day.

engine46
2007-10-10, 11:51 PM
Temperature directly affects density altitude. As temperature increases, so does density altitude. Therefore, at higher temperatures, the aircraft cannot perform as well in terms of thrust produced, efficiency, aerodynamic lift, and many others. This is why takeoff rolls in hot temperatures are much longer. Smaller GA aircraft can face serious problems performancewise at high altitudes in high temperatures.

adam613
2007-10-11, 12:51 AM
Cold air is more dense than hot air. Because of this, temperature has two effects on aircraft performance:

1) The wing of an airplane provides more lift in dense air. So if it is warmer outside, you need to get the airplane moving faster for the wings to provide enough lift to get you off the ground.

2) Engines perform better in denser air. So if you take off when it's hot outside, you won't get as much thrust from the engines. This leads to longer takeoff rolls, since it takes longer to get up to speed, and reduces maximum takeoff weight because it takes more thrust to move a heavier airplane.

Air gets more less dense as altitude increases. The effects of altitude are well-measured and documented, in that the instruction manual for an aircraft might say that at X altitude above sea level, your engines will operate at Y% of maximum efficiency and your stalling speed increases by Z knots above what it would be at sea level.

Density altitude is a measurement for the effects of air temperature. Say the density altitude is 4000 feet. That means that at the current temperature, your airplane will perform as if it were at 4000 feet at standard temperature. That, in combination with the actual altitude of the airport, allows you to compute the performance of your aircraft in terms of maximum takeoff weight and required runway length.

If you are ever in a city like Phoenix in the summer with a scanner, listen to the ATIS. It often specifies a density altitude. (Not that I recommend being somewhere like Phoenix in the summer. My avatar should indicate why I know this.)

PhilDernerJr
2007-10-11, 06:10 AM
As for spotting, cold air can negatively affect locations like Howard Beach, where the planes might get airborne sooner on the runway and turn off before it hits that sweet-spot for yo to take photos, or gain altitude too fast.

Derf
2007-10-11, 08:25 AM
Everyone knows that in the summer the temp rises very quickly on the hot tarmac. Due to this reason the airlines need to stock more drinks for the passengers thus more weight and a aircraft uses a longer take off roll in the summer. In the winter the pilots have to make sure they are lightly loaded as during the flight some snow may accumulate on the wings. We all know it is much colder at altitude and the chances of snow on the wings at that high altitude would increase weight. That is really why the F/A throws off the guy who was drinking at the bar but not really drunk.

My Name is Fred and I am a recent graduate from the Cliff Claven school of knowledge.
Glad I could help here with my vast knowledge of everything arodinamic.

PhilDernerJr
2007-10-11, 02:45 PM
Fred, I can't tell if you're serious.

But actually, when it comes to weights, the only weights I've seen change with seasons are passenger average weights, which come down in the summer because of the lack of jackets.

DHG750R
2007-10-12, 05:37 AM
the 747-400 pax range is higher than the freighter due to the freighter's higher max zero fuel weight (ZFW). 542,500lbs for the pax vs. 635,000lbs for the freighter. Both aircraft have the same maximum structural takeoff weight of 875,000lbs. This means you can carry less fuel before you reach maximum weight, this means less range of course.

It's not unusual for a -400F to carry as much as 273,000lbs of cargo. The typical passenger load with cargo is likely to not exceed 116000lbs (assuming 400pax @ 190lbs with 40,000lbs of bags and freight in the belly)

our -400'Fs are not equipped with fuel tanks in the horizontal stab, most pax -400's are typically equipped for longer range

Zero fuel weight is the weight of the airplane , loaded with everything ready to fly except for fuel.

PhilDernerJr
2007-10-12, 06:19 AM
Thanks for those numbers! Certainly clarified some of this for us.

With my experience with weights, the heaviest I've seen for a flight multiplied to 400 pax would still only bring the plane to about 141,000 lbs. That's a lot of extra room for cargo. It also shows how the older, more beat up cargo aircraft are profitable for cargo companies after pax airlines give them up....more weight allowed to make more money.

Derf
2007-10-12, 10:02 AM
Fred, I can't tell if you're serious.
.....


ahahahahah rrright, If I EVER make a serious statmenet like that, please ban me! :borat:

Hot long rollouts due to some extra L.I. Ice Tea, and snow accululations on the wing during flight? :borat:

The rest of this post was moved to a new thread

Idlewild
2007-10-12, 06:05 PM
As for spotting, cold air can negatively affect locations like Howard Beach, where the planes might get airborne sooner on the runway and turn off before it hits that sweet-spot for yo to take photos, or gain altitude too fast.

Unless it's a A340-200/300.

Informant
2007-10-15, 07:42 AM
Aicraft weight does not directly affect fuel consumption,just because you have a lot of bags it doesn't mean you need a lot of fuel...at all.

T-Bird76
2007-10-15, 12:04 PM
Aicraft weight does not directly affect fuel consumption,just because you have a lot of bags it doesn't mean you need a lot of fuel...at all.

Can you explain this further? I'm not a pilot so I don't understand how weight won't affect fuel consumption. I would assume its like a car, when I have a trunk load of stuff I burn more fuel moving the car forward.

PhilDernerJr
2007-10-15, 03:32 PM
I'm confused by that as well.

If two planes are flying the same distance, one a ferry flight and the other just under the MTOW, you're saying that both would burn the same amount of fuel?

lijk604
2007-10-15, 03:59 PM
Wow, as someone who used to W&B 747's daily to Tokyo, I highly disagree with that statement. Please explain Mr. Informant.

DHG750R
2007-10-15, 04:03 PM
I would agree , payload has a direct affect on fuel consumption.

hiss srq
2007-10-16, 12:08 AM
It does indeed have a direct affect. Espesially when you are forced to step climb due to your weight.

Informant
2007-10-16, 12:13 AM
Well let me explain it all to you.

You have an aircraft a 747 better yet, make it two.The first aircraft has its tanks all 10 tanks full and no payload except for a two-man crew. The second has full fuel as well but also is filled with cargo.
Both aircraft are the dsme make and model,both aircraft will fly the same route, both have the same amount of fuel.
Why will one burn up more than the other?
We all agree that the higher you cruise the less drag you encounter, the aircraft's limit on that is speed and weight, if you have the speed you can have the altitude..ie the concorde.
The second 747 being heavy will not be able to climb to that cruise altitude in the same time it will take the first one, even so, it will have to spend time at a lower altitude to burn off enough fuel to reach its desired cruise altitude. Sometimes when we fly to Asia form the east coast we may have to make a stop up north ot get more fuel because we won't have enough to continue due to our being too heavy to get up to our preferred/planned cruise level, and sometimes density altitude will just have us wasting gas on the tarmac because we will be too heavy to take off.

So weight does not directly control the amount of fuel you are required to have. Its the effects of what you are carrying/ how much you weigh which will determine how much fuel you burn.

DHG750R
2007-10-16, 03:21 AM
How about this , I have two flightplans in front of me , same aircraft going MIA-VCP . Each flightplan has different payloads. There is a 7 ton (15,432lbs) difference in the two. exactly the same flightplan route , same alternate , holding fuel and cruise altitude. The enroute winds are exactly the same. The enroute fuel burn is 12117kg (26,713lbs) per hour for the higher payload , while the lower payload has a fuelburn of 11803kg (26,020lbs) per hour.

The min fuel required for the heavier flightplan 104965kg
The min fuel required for the lighter flightplan 102498kg
2467kg difference :borat:

Further proof payload's affect on performance , for every 1000kgs of payload increase over the flightplan payload , our crews add 206kg of fuel

The pax 747 actually has 9 tanks (including one in each horizontal stabilizer), the freighter has 7

Mellyrose
2007-10-16, 07:23 AM
Aicraft weight does not directly affect fuel consumption,just because you have a lot of bags it doesn't mean you need a lot of fuel...at all.



So weight does not directly control the amount of fuel you are required to have. Its the effects of what you are carrying/ how much you weigh which will determine how much fuel you burn.



How do these 2 statements not contradict each other?


No offense, but you seem to be twisting words to try and stir something up and make others wrong who are actually just saying the same thing as you. I don't understand why.

Derf
2007-10-16, 08:26 AM
Aicraft weight does not directly affect fuel consumption,just because you have a lot of bags it doesn't mean you need a lot of fuel...at all.


ahahahahahah :borat:

um...YES IT DOES, PERIOD! I do not care how you word what ever sentences you want, the above statment is not true. Please tell me you are not doing weight an balance.

Informant
2007-10-16, 09:25 AM
No Mel not at all, wasn't my intention. A direct effect or direct correlation,meeans that there is an exact positive or negative relationship based on two givens, for example, the price of a steak, to how much it weighs.The price of the steak will go up, as the weight goes up-positive correlation/ a direct effect.
When I say there is no direct effect/'+'(positve) correlation between weight and how much fuel you need I am saying, there is no set equation where one adds a specific amount of fuel for every bag or piece of cargo added- that's what I feel is being said here and that makes no sense at all. Weight does have an effect on fuel consumption, but not directly- as I said before the weight will restrict you to a to certain altitudes and speeds which in turn will give you range and fuel burn issues.

Fred, I hope I don't have to do weight 'an' balance either', and ahahahahahaha x 2 because No it doesn't!

Derf
2007-10-16, 09:50 AM
Weight does have an effect on fuel consumption, but not directly
HUH?


as I said before the weight will restrict you to a to certain altitudes and speeds which in turn will give you range and fuel burn issues.
THUS More Weight is More fuel burn! :borat:

If I overload my car so it can not do more than 35mph, my fuel burn is going to be high with my peddal on the floor, but it is not my altitude that is affecting me that much, it is the fact that my car is overloaded. It is hard to move things, The more you need to move, the more power needed and the more power needed, will determine how much fuel you need. It is simple as this holds its weight in ANY application....even in space! If your space ship is 2x heavier, it will take more fuel to push it the same speed as a vehicle with less mass. I hope that is easier to understand. :borat:

Informant
2007-10-16, 11:18 AM
Fred, did you read the beginning of my last post where I explained what a direct effect was? For arguments sake okay, if you have more weight yes you will burn more fuel because of the effects of that weight on the performance of the aircraft. What I am arguing(and check my original unedited post) is you don't put on more fuel when, when you add more weight- if you're flying Memphis to Dubai your gonna have almost full tanks,if you add more cargo, you can only add so much more fuel. What happens when the tanks are full, and you still have more cargo to load?

lijk604
2007-10-16, 12:30 PM
What happens when the tanks are full, and you still have more cargo to load?
You leave cargo behind. Hence the corollary of more weight = more fuel. When you run out of room for fuel OF course you cannot add more weight, AND get to your planned destination.
I don't know how much simpler we can make this.

Informant
2007-10-16, 01:25 PM
Well then please do, I don't know how much more I can explain it.And im not gonna try, anyone at JFK? I'm thinking of heading down to P.R for the day.

mirrodie
2007-10-16, 02:20 PM
Aicraft weight does not directly affect fuel consumption,just because you have a lot of bags it doesn't mean you need a lot of fuel...at all.


You know, I think I finally figured out what the heck you were trying to say.

I just left the gym, had coffee and re-read this thread a few times, trying to figure out what you meant.


I think what you meant to say was:

"Aircraft weight is not directly proportional to fuel consumption."

Perhaps that is what you meant to say and subsequently are trying to explain.

cheers
Mario

Mellyrose
2007-10-16, 03:13 PM
I honestly think he is just trying to confuse the hell out of everyone and cause conflict.

Informant, you may be "right" with your tricky wording but seriously, I can't even read your posts they're so wordy and scattered...and if Mario just explained something more comprehensively on this board than someone else, than you should be ashamed. ;)

(PS: I'm sorry Mario...no offense)

PhilDernerJr
2007-10-16, 03:49 PM
i R wates n balintz.

DHG750R
2007-10-16, 04:22 PM
Most airline aircraft do not depart with full tanks unless the flight requires it. One thing I learned about flying passengers is, when working with a flight that may be close to full of paying customers and bags/cargo. You will sometimes restrict either to allow you to make it to your destination - nonstop. However , in the cargo business. You are much more likely to add a fuelstop in order to not leave anything behind.

Informant
2007-10-16, 05:54 PM
Yes Mario finally yes...Yes!
Thats exactly how I should have worded it.

And MEL..
Please,oh please... lighten up.
It was not my intention to confuse anyone.

mirrodie
2007-10-16, 07:06 PM
but seriously, I can't even read your posts they're so wordy and scattered...

Perhaps you meant to say that informant's posts are somewhat loquacious or verbose? Yet his initial post, "Aicraft weight does not directly affect fuel consumption,just because you have a lot of bags it doesn't mean you need a lot of fuel...at all." was relatively terse.



...and if Mario just explained something more comprehensively on this board than someone else, than you should be ashamed.


Hey now, since when are my explanations less than on key? Spelling and grammar have served me well. But don't knock me for never learning to type. Thankfully, in all my years in school, I found many a lovely lady to take care of typing for me.


(PS: I'm sorry Mario...no offense)

None taken.



And MEL..
Please,oh please... lighten up.
It was not my intention to confuse anyone.

Don't mind her. If she gets under your skin, just say, " I just saw Pink Delta again"


:wink: @ mel

Derf
2007-10-16, 11:45 PM
I still do not think you guys get it...If you have a plane that has a full payload and not enough fuel, when it reaches its destination it is literally on fumes and lands with all engines are flaiming out over the numbers....then you go back to the start of the flight and add 1000 pounds of anything but fuel, the aircraft given all the same setting will flame out before the threshold period. I have no idea what kind of crap we are tying to pull out of these statements but you guys should really be in management if you believe this stuff!

OF COURSE wind resistance of the airframe is changing the fuel burn depending on the aircraft...HELL vortices generators add drag! With this knowledge, it will not be an exact pound per pound as the aircraft is also trying to overcome other variables....IT STILL DOES NOT CHANGE THE FACTS. So with this knowledge, It will not take a whole lot of fuel to push my 175lbs a$$ across the pond if I am added to a 747.....BUT IT DOES TAKE MORE FUEL, unless you want to use some reserves wich ARE padded in case of small errors...but it does take a hell of a lot more to move the aircraft pound per pound as when I am inside, the wind resistance is not changing.

If you disagree...just remember, it is ok to be wrong. Weight does directly affect the fuel needed....I am not saying pound per pound but that really does not matter in this case or any case.

Add Mass and you MUST add fuel unless you are working into the reserves.....when dealing with a 747, one person is no big deal, it may make a 20 mile difference or a .2 mile difference but it will not benefit...YOU ALWAYS LOOSE WITH MORE WEIGHT.



(FOR KICKS... if you really want to see fuel burn go up, take a 747 and climb at a little slower speed than documented and watch the fuelburn soar....think of it as a boat not getting up on the step....LOTS OF POWER, LITTLE RESULT -add a tiny bit of power and few knots and the boat gets up on the step and really starts to move)

mirrodie
2007-10-17, 09:59 AM
I still do not think you guys get it......

I have no idea what kind of crap we are tying to pull out of these statements but you guys should really be in management if you believe this stuff!

...Weight does directly affect the fuel needed....I am not saying pound per pound but that really does not matter in this case or any case.



Fred, perhaps you did not read my last post? We got it. The misunderstanding was cleared up.
I'll be honest, when I first read informants post, I too was like "what is this guy on?!" Thanks goodness for coffee. :mrgreen:

It was simply a matter of deciphering his post.

What Informant, like you Fred, meant to say is the weight affects the fuel burn, but not in a pound for pound (hence a direct relationship) way

To recap, weight does directly affect the fuel needed. BUT what informant MEANT to say that this relationship was not DIRECTLY proportional.

Instead, fuel burn is, I am assuming, calculated in a multifactorial equation, where weight is only one of the variables considered.

So, for instance:

a=b, where a is weight and b is fuel burn, is wrong as this notes a directly proportional relationship.

whereas the true calculation of fuel burn is more likely to be something more like

b = a + c/d-f x gx3 / 0.05 where weight plays a role but all those other variables do too.

It's truly a matter of physics and math coupled with a multifactorial relationship.

Any more 747 questions? This is a good thread. Learning a lot about the 747.


Actually, may I shift gears a bit? Winglets seem to somehow be more efficient regarding fuel burn, right?
If my assumption is correct, then why don't most or all planes, older 747s in particular, get retrofitted with winglets? I assume there is a tradeoff.

Derf
2007-10-17, 10:12 AM
I think you need to have come more coffee and reread my post Mario :wink:

Derf
2007-10-17, 10:36 AM
It is still total BS.... If I have a stripped out 74 and you have a fully loaded 74 and I am flying in formation with you to the destination, you will have a higher n2 than me and you WILL be burning more fuel and it has nothing to do with altitude as both aircraft are at the same altitude. if it is one pound more weight, it is hard to see...ad 5000 pounds and then 20,000 pounds and you can see how much a difference. take altitude out of the equation and other BS does not change facts... More weight, more power...more power more fuel, Period! It is black and white, no room for wiggle here.

If you have a higher altitude, you are reducing DRAG...increasing the effectiveness of the engines, thrust and fuel burn (MAJOR ADVANTAGE). But that was not the discussion until later in your postings.

Why are we still talking about this?

PhilDernerJr
2007-10-17, 11:32 AM
It was over, until you posted. :evil:

As for the winglets, isn't the wing of the classic 747s different from the current? I would think they'd need a new winglet design and that the cost of adding them, and the time taking them out of revenue service, might not be worth it financially.

Derf
2007-10-17, 12:04 PM
Here is a clip on the 747-400 wing...I was not aware that there was a size change...figured there was a weight difference.


In order to enhance fuel efficiency the 747-400 wings were redesigned, increasing the wingspan from 195ft 8in (59.6m) to 211ft 5in (64.4m). Additional 6ft-high composite winglets have been added, angled upward and marginally outward from the wing tips. The aerodynamic characteristics of these winglets provide a disproportionately superior lift-to-wing-surface-area effect to the wing as a whole without increasing overall wingspan or drag.

The wing weight was reduced even after the increase in wingspan due to the use of high strength aluminium alloys and composite materials. The winglets give the 747-400 a fuel mileage improvement of 3% and their upward angle means that the overall wingspan remains within the standard airport apron slot.

Aerodynamic improvements to the wing-to-body fairings, engine nacelles and engine struts have been implemented to reduce drag. Boeing's suppliers such as GKN, Daewoo, Fuji Heavy Industries, Parker Aerospace and Yokohama Rubber have enabled airframe weight to be reduced in a number of areas by using composite materials such as graphite-epoxy, special aluminium alloys and honeycomb materials.



Small company sells Boeing on idea of adding winglets
Monday, September 11, 2000
By JAMES WALLACE
SEATTLE POST-INTELLIGENCER REPORTER

Only a few years ago, Boeing's top airplane designers scoffed at the notion of putting winglets on the company's jetliners.
Those sexy tips at the airplane wing's end, they believed, did little to improve performance and were mostly for show, a fashion statement of the rich and famous who could afford a private business jet.
Then Boeing discovered that a "blended" winglet designed by a small Seattle company could do wonders for the next-generation 737.
Now, Boeing is looking at blended winglets for what could be one of its most important airplanes this decade -- a stretch version of the 747 that will go head to head against the Airbus A3XX superjumbo.
Aviation Partners, the small Seattle company that had a better idea, is flight testing a leased 747 freighter fitted with the 15-foot-high blended winglets.

Initial indications are that the winglets will reduce drag by 6 to 7 percent, said Joe Clark, chief executive officer of Aviation Partners. More complete data will not be available until the end of the month or later.
Making the 747 more efficient is critical to Boeing's success in the upcoming jumbo showdown with Airbus.
The European airplane maker has promised potential customers that the 555-passenger A3XX will be at least 15 percent more efficient than the 416-passenger 747-400. And Boeing is claiming that a 100-passenger stretch of its jumbo will be at least as efficient as the Airbus behemoth, even though the 747 is a 1960's design.
Boeing has not yet decided to put blended winglets on the 747-400X Stretch, as the longer jumbo jet is known. In fact, Boeing engineers are leaning toward raked wingtips, which could also improve performance. Raked tips were used for the first time on the new Boeing 767-400 that will soon enter service with Delta and Continental airlines.
But even if blended winglets are not used on the 747-400X Stretch, their day is coming for most Boeing models now in production, including older 747s.
"The market is huge, absolutely huge," said Clark, who co-founded the company in 1991. "We have just begun to scratch the surface."
The idea took root when Montana businessman Dennis Washington called Clark and asked his friend if anything could be done to extend the range of Washington's Gulfstream II business jet.
Clark gathered a team of mostly retired Boeing and Lockheed Martin engineers.
The blended winglet the team designed reduced the drag on Washington's Gulfstream II by more than 7 percent. Next came FAA certification.
Today, about 50 percent of the world fleet of more than 200 Gulfstream II jets have been retrofitted with blended winglets, at a cost of about $495,000 per plane.
At the recent Farnborough international air show near London, Clark announced that blended winglets will be available next year for Hawker business jets -- a potential market of some 500 planes. Dassault Falcons could follow.
Winglets were common on business jets before Aviation Partners arrived on the scene.But those traditional winglets, which are also found on all Airbus models and the Boeing 747-400, rise at a sharp angle from the wing.
Blended winglets gently curve up, as if they are part of the wing.
Winglets were first developed by NASA in the 1960s to help reduce drag. Increasing the wing span can produce the same results. But wings of jetliners can't get any longer and still fit at airport gates. That's why Boeing decided to put a traditional winglet on its 747-400, the fourth generation of its aging jumbo jet.
At the Paris Air Show in 1997, Boeing's Borge Boeskov approached Clark about blended winglets on the planned Boeing Business Jet, a next generation 737-700 with the strengthened wing of the 737-800.
Clark's subsequent business proposal for Boeskov said the Boeing Business Jet would get from 4 to 5 percent better performance with blended winglets.
"Borge sat down with me and said, 'The corporate guys like the looks of these things because they differentiate the product, but frankly my engineers have told me they don't work,'" Clark recalled.
So Clark told Boeskov his small company would foot the bill to design winglets for the Boeing Business Jet if Boeskov would test fly them on the plane.
Unable to get Boeing engineers to go along, Boeskov turned to an old friend, the German carrier Hapag-Lloyd, a longtime Boeing 737 customer. Hapag-Lloyd supplied one of its new 737s, and the results were better than Clark had predicted -- a nearly 7 percent reduction in drag.
The winglets for the Boeing Business Jet are 8 feet 3 inches high.
By the time of the 1999 Paris Air Show, Boeing and Aviation Partners had formed a joint venture.
Since then, Aviation Partners-Boeing has been very busy. Boeing announced earlier this year that blended winglets would be offered not only on its business jet, but as a factory option on 737-800s. And they will eventually be available for the 737-700 and for the new 737-900.
In March, South African Airways became the first airline to order winglet-equipped 737-800s. It was an important victory. Boeing beat out Airbus, which was offering its A320.
"I really believe that was the first time that Boeing realized there is a real benefit to the airlines," Clark said.
More recently, American Trans Air, the nation's 11th-largest airline, ordered 20 next-generation 737-800s with winglets.
As part of its joint venture with Boeing, Aviation Partners can retrofit existing planes with blended winglets. It has already signed contracts to retrofit about 70 737-800s with blended winglets, including 26 for Hapag-Lloyd and 19 for Air Berlin.
Deals with several other customers are in the works, Clark said.
Aviation Partners is also looking to retrofit Boeing's fleet of older "classic" 737s. It has completed a blended-winglet design for the 737-300. Flight tests could begin late this year.
The Federal Aviation Administration last week certified the blended winglets for the Boeing Business Jet. Certification for the 737-800 winglets is expected early next year.
About 800 of the 737-800s will have been delivered before the winglets are certified and Boeing can begin adding them in the factory. Clark expects about half those 800 planes will eventually be retrofitted with winglets.
Blended winglets are also planned as a retrofit option for operators of Boeing 757s, 767s and 747s, Clark said, noting that the payoff on long-haul planes will be significant for an airline.
"If we can save an airline 5 percent a year on fuel, that's huge," he said.
That's why Aviation Partners is paying for the current 747 flight testing. It hopes to one day retrofit hundreds of older 747s with blended winglets, assuming the flight test results come out as expected.
"We are not a big company," Clark said. "These big planes are real expensive to fly. When you load that baby with 56,000 gallons of fuel and pull out your credit card . . ." His sentence trailed off in laughter.
Those tests, using a leased 747-200 freighter, are being flown out of the former George Air Force Base near Los Angeles. Later, the same plane will be fitted with raked tips by Boeing for a comparison before it firms up the design for the 747-400X Stretch.
Boeing wind tunnel tests found that a raked tip on the 767-400 would provide better operating efficiency than traditional winglets such as those on the 747-400.
The recently completed 767-400 flight test program showed the raked tips boosted the plane's fuel mileage up to 1.5 percent better than the wind tunnel tests had predicted.
The blended winglets being tested on the 747 in California are more than twice as big as the winglets on the 747-400. So it remains to be seen if Boeing will opt for blended winglets or raked tips on the 747-400X Stretch.
Either way, it won't be that many years before passengers flying on many Boeing jetliners look out at the window and see the graceful curve of a blended winglet, according to Clark.
"We are looking at a business plan of (retrofitting) from 1,500 to 2,500 planes in the next five or six years," Clark said.
"We have customers screaming for them."
http://seattlep-i.nwsource.com/dayart/2 ... nglets.jpg (http://seattlep-i.nwsource.com/dayart/20000911/winglets.jpg) http://seattlep-i.nwsource.com/dayart/2 ... glets2.jpg (http://seattlep-i.nwsource.com/dayart/20000911/winglets2.jpg)

You would bet that if there was a good fuel savings...they would have done it.
Correction...they did it!
http://www.tropicalisland.de/united_ara ... x2000.html (http://www.tropicalisland.de/united_arab_emirates/dubai/dubai_airport/pages/DXB%20Dubai%20International%20Airport%20-%20Emirates%20Airlines%20Airbus%20A330-200%20aircraft%20with%20Cargolux%20Boeing%20747-200%20aircraft%20with%20winglets%203008x2000.html)

http://www.tropicalisland.de/united_arab_emirates/dubai/dubai_airport/images/DXB%20Dubai%20International%20Airport%20-%20Emirates%20Airlines%20Airbus%20A330-200%20aircraft%20with%20Cargolux%20Boeing%20747-200%20aircraft%20with%20winglets%203008x2000.jpg

I guess I just proved myself wrong when I stated that more weight will always = more fuel....woops :lol: :borat:

T-Bird76
2007-10-17, 12:11 PM
Evergreen is currently looking into adding Winglets to their 100/200s

Informant
2007-10-17, 07:28 PM
I still do not think you guys get it...If you have a plane that has a full payload and not enough fuel, when it reaches its destination it is literally on fumes and lands with all engines are flaiming out over the numbers....then you go back to the start of the flight and add 1000 pounds of anything but fuel, the aircraft given all the same setting will flame out before the threshold period. I have no idea what kind of crap we are tying to pull out of these statements but you guys should really be in management if you believe this stuff!

You wouldn't get to your destination on fumes...you would divert! You wouldn't spend your reserves on trying to get to your original destination. And yes, we do get it!


YOU ALWAYS LOOSE WITH MORE WEIGHT
That was said in other terms.


If you have a higher altitude, you are reducing DRAG...increasing the effectiveness of the engines, thrust and fuel burn
But you wont be able to get to a higher altitude because you are so heavy, you will have to wait!
Altitude increases effectiveness of engines? What? To be able to cruise at higher altitudes, you need to have engines that can push you around at a higher speed.


slower speed than documented
On takeoff climb your pulling V2 plus 5-15kts? Is that not slow enough?

PhilDernerJr
2007-10-17, 07:59 PM
Guys. Please stop the fuel/weight debate. It's going nowhere and we're on other 747-related topics. I'm asking this as a member, not a mod.

Derf
2007-10-17, 08:00 PM
agreed :borat: