Iainhol From , joined Dec 1969, posts, RR: Reply 1, posted (12 years 8 months 1 week 3 days 7 hours ago) and read 1781 times:
UA took them off one 744 to compare its performance. Well it made no difference it the performance or fule consuption. Boeing offered to take them off but non of the airlines wanted to as it imakes the 744 reconisable!
Iain
Sammyk From United States of America, joined Oct 1999, 1686 posts, RR: 0 Reply 2, posted (12 years 8 months 1 week 3 days 7 hours ago) and read 1760 times:
Aviation Partners, the firm that developed the blended winglets for the 737/BBJ is running experiments on the 747-200. Supposedly they are achieving lower fuel burn.
Jet Setter From , joined Dec 1969, posts, RR: Reply 3, posted (12 years 8 months 1 week 3 days 7 hours ago) and read 1734 times:
Winglets on B747-400s do account for around a 5% cut in fuel consumption, and also increase MTOW.
In late 1999 British Airways operated G-BNLR for a week without it's port winlet, after it had been damaged but could not immediately be replaced.
Handling minus the winglet was identical, but without winglets induced drag is higher. With the port winlet missing the BA B747-400 suffered a 2.5% increase in fuel consumption, and Max Take off weight had to be reduced by 9.5T.
If the winglets served no purpose, why would airlines fly them around, adding to the weight of their aircraft. Why would Aviation Partners be developing winglets to retrofit onto B747-200s and B737NGs?
Aviation Partners actually have a B747-200 test flying with 4.42m (16ft 6in) winglets at the moment, which are scaled up versions of those they developed for the 737NG/BBJ. On the 747-200 they reduce fuel consumption by 6-7%. The winglets can be retrofitted onto all B747-200/300s and even -400s because the blended winglets are more effective than existing B747-400 winglets
Iainhol From , joined Dec 1969, posts, RR: Reply 4, posted (12 years 8 months 1 week 3 days 6 hours ago) and read 1726 times:
Jet Setter from what I heard from a mechanic was that UA took one of for the week and it made no difference. Some winglets work like the Gulfstream 5 ones and the A340 ones but theh 747-400 one is not effecient. If you read my post I said it made no difference so basically it supports its own weight and not do all what Boeing said it does!
Iain
Yaki1 From , joined Dec 1969, posts, RR: Reply 5, posted (12 years 8 months 1 week 3 days 6 hours ago) and read 1696 times:
Points of interest: I hear Aviation Partners and Hexcell are working with a AA737-300 for a winglet retrofit. I believe JAL has 747-400s without winglets for domestic use.
AussieErj145 From , joined Dec 1969, posts, RR: Reply 7, posted (12 years 8 months 1 week 2 days 21 hours ago) and read 1652 times:
Aviation Partners of Seattle has been flight testing 4.3 metre high winglets that promise a 6-7% drag reduction not a 6-7% fuel burn reduction. The aircraft being used is a 747-200 freighter, with unpainted fuselage, and what looks like a solid black tail. I can't see the reg number.
AussieErj145 From , joined Dec 1969, posts, RR: Reply 8, posted (12 years 8 months 1 week 2 days 21 hours ago) and read 1644 times:
Aviation Partners of Seattle has been flight testing 4.3 metre high winglets that promise a 6-7% drag reduction not a 6-7% fuel burn reduction. The aircraft being used is a 747-200 freighter, with unpainted fuselage, and what looks like a solid black tail. I can't see the reg number.
C172sb From , joined Dec 1969, posts, RR: Reply 10, posted (12 years 8 months 1 week 2 days 20 hours ago) and read 1638 times:
I saw a picture of those winglets on the 747-200 in Flight International, I believe. They look huge, compared with the ones on the 744 they stick upright and are very tall.
Jet Setter From , joined Dec 1969, posts, RR: Reply 11, posted (12 years 8 months 1 week 2 days 15 hours ago) and read 1619 times:
The data is from a Flight International article about British Airways operation of the B747-400 without a winglet, and yes the quoted figures were 2.5% fuel burn penalty and 9.5T MTOW penalty. It is a lot!
AFa340-300E From France, joined May 1999, 2084 posts, RR: 28 Reply 12, posted (12 years 8 months 1 week 2 days 10 hours ago) and read 1585 times:
Hello,
Of course the winglets are of some use. These fitted on the Boeing 747-400s give the advantages reported by Jet Setter. Otherwise they'd have been removed, as they add some weight to the aircraft.
Now, the winglets possibly to be fitted on the Boeing 747 Classics would be more efficient. I'm not sure they would reduce drag more than these of the Boeing 747-400, but as they'll be blended winglets, there'll no longer be any need for major end-wing reinforcement to carry it.
The Boeing 747-400Ds used by JAL and ANA on their domestic networks are not fitted with the winglets because the gain in fuel consumption on such short hauls don't outweigh the extra-weight.
Sammyk From United States of America, joined Oct 1999, 1686 posts, RR: 0 Reply 14, posted (12 years 8 months 1 week 2 days 9 hours ago) and read 1572 times:
Thats a Singapore 744 Winglet. I agree, nice shot.
Avilitigator From United States of America, joined Aug 2000, 214 posts, RR: 0 Reply 15, posted (12 years 8 months 1 week 2 days 8 hours ago) and read 1553 times:
Does anyone out there know how the winglets decrease drag and reduce fuel burn? I know this is what we read about, but what are the physics behind winglets?
Do they provide extra lift? If so, what is the advantage of fitting them at an angle or blending them to the regular wing?
I ask this because the 767-400 has the raked wingtips, which essentially look like the winglets on a B744 or A340 except the 767-400s' wingtips aren't angled upwards.
Navion From United States of America, joined May 1999, 981 posts, RR: 1 Reply 17, posted (12 years 8 months 1 week 2 days 8 hours ago) and read 1543 times:
Hi Iainhol. I just wanted to say I believe the United mechanic you refer to is not right. The winglets on the 744 have a very positive effect on long haul flights. I will agree with you the blended winglet is a greater evolution of winglet design and is more efficient, but the 744's winglets are effective. The only reference to flying without them is A) short hauls do not take advantage of winglet performance (except for hot & high airports), and B) if a 744 has to, it can fly without one of it's winglets without an adverse affect in handling.
Avilitigator From United States of America, joined Aug 2000, 214 posts, RR: 0 Reply 19, posted (12 years 8 months 1 week 2 days 7 hours ago) and read 1528 times:
Iainhol,
Yes, we do read the posts and there is nothing wrong with us. So far there haven't been any posts providing a scientific explanation regarding the efficiency of winglets. Your posts explaining winglet efficiency were based on secondhand information but if you or anyone else know of any publications or physics manuals on wing designs, that would contribute greatly here.
Iainhol From , joined Dec 1969, posts, RR: Reply 20, posted (12 years 8 months 1 week 2 days 6 hours ago) and read 1524 times:
I agree winglets work and do a good job, but the 747-400 winglets do not work as well as Boeing had planned. The tests on the UA 747-400 happend quite a while ago, and Boeing did offer to take the winglets off but the airlines kept them as they support themselves the easiest way to tell a 744 is by the winglets! I do not know enough about winglets to figure out all what is going but I will try and get the guy i spoke to come here and tell you guys more about the findings!
Iain
Saluki777 From , joined Dec 1969, posts, RR: Reply 21, posted (12 years 8 months 1 week 2 days 6 hours ago) and read 1522 times:
The way the winglets work is not too hard to understand. At the end of all airplane wings, vortices known as "wingtip vortices" form where low pressure air above the wing draws high pressure air from below the wing up around the end of the wing. Somehow this creates drag. The winglets prevents the formation of wingtip vortices, hence less drag.
Another note about 747 evolution: I read that when Boeing introduced the extended upper deck on the 747-300 (& 400 for that matter), the changed contour of the upper deck allowed cruise speed to increase to Mach .85 from .84 on the 200.
Adria From , joined Dec 1969, posts, RR: Reply 24, posted (12 years 8 months 1 week 2 days 6 hours ago) and read 1510 times:
Dream on
25 Avilitigator: Thanks Saluki777 for the clear and simple explanation that winglets reduce/eliminate wingtip vortices, thereby reducing drag. Do the 767-400 raked win
26 C172sb: some of them are not that old, the last one was built in 1991. http://www.boeing.com/commercial/747/evolution.html
27 Boeing747-400: What's that supposed to mean? You make no sense at all. I was just speculating that a winglet on ANY 747 would be better. It's true, I would love for
28 Oxygen: I read somewhere that boeing did not put winglets on the 777 in the beginning is because they think that the 777 wing is so efficient that it does not
Sponsor Message: 
From United States of America, joined Jul 2000, 863 posts, 
From , joined Dec 1969, posts, 
From , joined Dec 1969, posts, 
From France, joined May 1999, 2084 posts, 
From South Africa, joined Nov 1999, 1098 posts, 
From , joined Dec 1969, posts, 
Printer friendly format 
