Jaml10-11 From United States of America, joined Jul 2002, 9 posts, RR: 0 Posted (13 years 10 months 18 hours ago) and read 2857 times:
The new generation of commercial jets, have winglets and wing fences incorporated in high-efficiency wings for overall fuel economy and aerodynamic performance; which may be one in the same.
Airbus uses winglets on all of their models from the A-319 to the A-340-600; however only the Boeing 747-400 and the B767-400 has them. Why?
Could anyone shed some light on if Boeing’s Engineers have at anytime studied the viability of retro-fitting early production B757, 767-200 and especially B767-300(ER’s) and 777 with winglets for increased fuel efficiency and performance for long-haul routes.
Any insight on this would be much appreciated.
B747skipper From , joined Dec 1969, posts, RR:
Reply 1, posted (13 years 10 months 18 hours ago) and read 2846 times:
Winglet "retrofits" for other airplanes as the ones listed "are coming"...
They will be either designed by the manufacturer or independant companies...
There are older 737 and Gulfstreams... or other airplanes that are retrofitted with winglets... an old 747 has been retrofitted with winglets...
Jetguy From , joined Dec 1969, posts, RR:
Reply 2, posted (13 years 10 months 18 hours ago) and read 2848 times:
For what it's worth, I believe that it was Marcel Dassault, the famous French aircraft designer, who said that properly designed wings don't need winglets. I'm not an aeronautical engineer by any means, but I've flown thousands of hours in turbojet aircraft that were essencially identical except some had winglets and some didn't. My personal observation is that whatever small performance gains they provide often is usurped by the handling penalties they impose. Additionally, from what I've heard and read, their design is still somewhat of a "black art" and claims for increased efficiencies can often be tenious at best. It seems to me that few new aircraft with "clean sheet" wing designs, such as the Boeing 777, incorporate them, while airframe manufacturers will incorporate them on "old technology" designs (B747-400) that they're trying to improve aerodynamically. Winglets are much cheaper to incorporate on older airfoil designs- they have minimal redesign and certification costs.
PPGMD From United States of America, joined Sep 2001, 2453 posts, RR: 0
Reply 4, posted (13 years 10 months 13 hours ago) and read 2798 times:
What Jetguy says about Winglets was the impression that I get from Aerospace engineers. To sum up what a doctor in Aerospace Engineering told me: "You know what the winglets are good for on most aircraft? The company logo."
He said that in most cases the improvements overall were marginal at best (barely enough to justify the cost of retrofit, and STC) and he saw little use of them.
This is coming from him not me. Almost everything he said about the math goes way over my head.
Jaml10-11 From United States of America, joined Jul 2002, 9 posts, RR: 0
Reply 5, posted (13 years 10 months 12 hours ago) and read 2788 times:
In response to Planeguy, the Airbus A300-B4 didn't have winglets, but the A300-600R's and A310's have; what are commonly known as, wing fences.
You are right, the B767-400's do not have winglets but have; what are accurately, called wingtip extensions.