AA737-823 From United States of America, joined Mar 2000, 5638 posts, RR: 11 Posted (9 years 2 weeks 6 days 5 hours ago) and read 2470 times:
I thought I'd start a topic to see if anyone knew about the progress of the winglet testing on the 757-200s.
Someone mentioned, in another post, that the 752 might lose CatIII autoland because the plane was floating too much on short final.
If so, wouldn't that negate any cost benefit the winglets would earn? Having to divert to an airport with better weather is not free...
Skibum9 From United States of America, joined Nov 2001, 1229 posts, RR: 0
Reply 1, posted (9 years 2 weeks 6 days 5 hours ago) and read 2449 times:
I've got a good question.....
Right now with a typical, non-winglet 757, additional spacing is given to planes behing them because of wake turbulence. After a take off roll of a 757, typically a plane behind it, waiting to take off, will be held 120 seconds to allow the wake turbulence to subside. With the new winglets, will this diminish the wake turbulence sufficiently to enable reduced spacing behind a 757 with winglets? In theory, I would think so.
Someone in a different thread that the wake turbulence was caused by the configuration of the wing, and the winglets wouldn't do too much to alleviate it. I am by no means an expert, but that is what I heard.
Nbgskygod From United States of America, joined May 2004, 726 posts, RR: 1
Reply 5, posted (9 years 2 weeks 6 days 1 hour ago) and read 2310 times:
The wake turbulence separation is based on aircraft weight rather than wing design. Since the 757 is close to the heavy weight category they gave it a separate category. So the application of winglets would have no affect on the wake turbulence separation, even if it did change the characteristics of the vortex off the wing.
"I use multi-billion dollar military satellite systems to find tupperware in the woods."
N1120A From United States of America, joined Dec 2003, 26196 posts, RR: 76
Reply 8, posted (9 years 2 weeks 5 days 20 hours ago) and read 2067 times:
Quoting Nbgskygod (Reply 5): The wake turbulence separation is based on aircraft weight rather than wing design. Since the 757 is close to the heavy weight category they gave it a separate category. So the application of winglets would have no affect on the wake turbulence separation, even if it did change the characteristics of the vortex off the wing.
The reason of the Wake/Weight corrolation is because of the larger wingspan and width of the cabin, and what that does to wind displacement. The DC-10's configuration actually gives it a much stronger wake than the 747, even though it is much lighter. Most DC-8s are heavier than the 752, but they don't have wake cautions because of their configuration. The 752's design created a very strong wake (stronger than its sister 767) and required a warning from ATC.
Winglets will not change this
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Uswyjer From , joined Dec 1969, posts, RR:
Reply 9, posted (9 years 2 weeks 5 days 19 hours ago) and read 2048 times:
that's my pic above! Sorry about the quality we were taking off and i just shot where it was parked and hoped my digital would focus on the right spot... and by some miracle it did. It landed as we were waiting in line with an America West CRJ900 and a bunch of overflow fighters from Monthan, it looked really sleek with the high winglets.