EHHO From Bulgaria, joined Dec 2005, 815 posts, RR: 8 Reply 2, posted (6 years 11 months 2 weeks 15 hours ago) and read 6747 times:
Because there's a profitability curve for installing winglets. Mind you, these are pretty heavy, tall things. They adjust the aerodynamic profile of the plane slightly, thereby increasing efficiency of fuel-burn. This efficiency occurs only at flights above a certain break-even distance. Given the purposes for airlines like AA and CO to retrofit their 737NGs with winglets, I'd say this breakeven point is somewhere around 1200-1500nm.
737-600 are Boeing's unfortuante attempt at creating an RJ with 737 commonality, never mind that the 737 platform is unfit to compete with modern day RJs (the 737-100 was of course nothing other than an RJ, but that was in the 60s). Given that RJs don't usually fly distances of 1200-1500nm, it is not profiatble to install 737NG-custom winglets on them. They will cost more than they'll save on fuel burn.
"Get your facts first. Then you may distort them as much as you please" -- Mark Twain
Dutchjet From Netherlands, joined Oct 2000, 7864 posts, RR: 58 Reply 3, posted (6 years 11 months 2 weeks 15 hours ago) and read 6747 times:
Quoting NewSky (Reply 1): Not sure if the -900 did. Only the new -900ER. Maybe you can get them with winglets but the airlines that ordered them chose not to.
Of course, winglets are available for the 73G and 738......but I am not sure if a winglet has been certified for the 736 or 739 (non ER version), likely due to the fact that the 736 and 739 have been produced in smaller numbers. While the winglets do make an aircraft more effecient, the cost of developing the winglet and getting the modification certified is also quite expensive, and its possible that the costs dont make sense on the variants will small production runs.
LN-KGL From Norway, joined Sep 1999, 803 posts, RR: 4 Reply 4, posted (6 years 11 months 2 weeks 14 hours ago) and read 6729 times:
I think it's more a stability problem. Without winglets the wingspan is already longer the total length of the 736 - hence a very unstable aircraft. With the winglets added it would be even more unstable longitudinal.
TinPusher007 From United States of America, joined Feb 2005, 963 posts, RR: 2 Reply 6, posted (6 years 11 months 2 weeks 10 hours ago) and read 6525 times:
One of the main, often-stated problems with the 736 in particular is that it is too heavy as a 100 seater. And, as has been stated, the winglets are heavy and would further add weight to an airplane that many operators consider to be overweight as is. Furthermore, I don't believe the mission profile for the 736 is such that the aerodynamic benefits would justify the costs and added weight of the winglets.
"Flying isn't inherently dangerous...but very unforgiving of carelessness, incapacity or neglect."
LN-MOW From United States of America, joined Jan 2000, 1897 posts, RR: 15 Reply 8, posted (6 years 11 months 2 weeks 10 hours ago) and read 6505 times:
Westjet is getting winglets for their 736's. I beleive they start with certification in the fall. As it takes around three months to get them certified, they don't want to pull an aircraft from traffic during the busy summer period.