CX flyboy From Hong Kong, joined Dec 1999, 6341 posts, RR: 56 Reply 1, posted (12 years 2 months 3 weeks 14 hours ago) and read 722 times:
The winglets only save fuel on longer haul flights. On short haul flights they only really add to the weight of the aircraft and do not provide a significant fuel (money) saving, so they had them removed.
A40-TY From United Arab Emirates, joined Apr 2000, 143 posts, RR: 0 Reply 3, posted (12 years 2 months 2 weeks 4 days 13 hours ago) and read 658 times:
The 747-400D model does not require winglets as these features are fitted (to standard 747-400's) to save fuel and improve performance.
The 747 Domestic's are used on the busy Tokyo-Osaka routes in Japan, amongst other busy internal services. The range therefore of the 'Domestic' aircraft is only about 4000km, there is therefore no need to have extensive fuel and performance related features, as opposed to the normal 747-400.
However, the 747-400D has been built in such a way as that in future, these aircraft can be modified to serve longer haul routes, which would mean installing the winglet features and increasing fuel capacity, as well as extensive cabin refurbishment.
With so many short haul cycles on the airframe, the aircraft would be able to operate on long haul services for a considerable amount of time for their remaining economic lives.