Originally Posted by Informant
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
And I, I took the path less traveled by
and that has made all the difference......yet...
I have a feeling a handle of people are going to be very interested in what I post in the near future.
http://www.jetphotos.net/showphotos.php?userid=187
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)
i R wates n balintz.
Email me anytime at [email protected].
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.
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.
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.
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.
None taken.
Don't mind her. If she gets under your skin, just say, " I just saw Pink Delta again"
@ mel
And I, I took the path less traveled by
and that has made all the difference......yet...
I have a feeling a handle of people are going to be very interested in what I post in the near future.
http://www.jetphotos.net/showphotos.php?userid=187
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)
The three most common expressions in aviation are, "Why is it doing that?", "Where are we?" and "Oh Crap".
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.
And I, I took the path less traveled by
and that has made all the difference......yet...
I have a feeling a handle of people are going to be very interested in what I post in the near future.
http://www.jetphotos.net/showphotos.php?userid=187
I think you need to have come more coffee and reread my post Mario
The three most common expressions in aviation are, "Why is it doing that?", "Where are we?" and "Oh Crap".
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?
The three most common expressions in aviation are, "Why is it doing that?", "Where are we?" and "Oh Crap".
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.
Email me anytime at [email protected].
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.You would bet that if there was a good fuel savings...they would have done it.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/2 ... glets2.jpg
Correction...they did it!
http://www.tropicalisland.de/united_ara ... x2000.html
I guess I just proved myself wrong when I stated that more weight will always = more fuel....woops :lol: :borat:
The three most common expressions in aviation are, "Why is it doing that?", "Where are we?" and "Oh Crap".
Evergreen is currently looking into adding Winglets to their 100/200s
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!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!
That was said in other terms.YOU ALWAYS LOOSE WITH MORE WEIGHT
But you wont be able to get to a higher altitude because you are so heavy, you will have to wait!If you have a higher altitude, you are reducing DRAG...increasing the effectiveness of the engines, thrust and fuel burn
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.
On takeoff climb your pulling V2 plus 5-15kts? Is that not slow enough?slower speed than documented
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.
Email me anytime at [email protected].
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