Prebennorholm From Denmark, joined Mar 2000, 6389 posts, RR: 54
Reply 3, posted (14 years 1 month 1 week 6 days 15 hours ago) and read 1137 times:
Aeh, winglets... The wing generates lift by accellerating air masses downwards. Outside the wing tip the air is of course not accelerated downwards. Therefore the air is put into a rotating "vortex" at the wing tip.
The winglet is not just a plate. It's has a carefully designed profile and its angle to the flight direction is carefully calculated too.
By taking energy from the vortex the winglet works much the same way as a sail on a sailboat. It Takes energy from the vortex and converts it into a little assistance to the engines pulling the aircraft forward.
Since the winglet takes energy from the vortex, it also reduces the vortex energy. And since vortex energy is all "lost lift", then the winglet also makes the wing generate a little more lift.
Exactly the same could have been achieved by a slightly increased wing span. But the further out the lift is generated, the stronger the wing must be. A stronger wing means either a heavier or a thicker wing, and both have negative influence on the aircraft performance.
It's all compromises. But when well designed winglets can save a few percent fuel.
Always keep your number of landings equal to your number of take-offs, Preben Norholm
Crjmech From United States of America, joined Jun 2000, 260 posts, RR: 1
Reply 6, posted (14 years 1 month 1 week 6 days 8 hours ago) and read 1085 times:
Besides providing aerodynamic benefits and acting as mechanic retainers, winglets are great for slowing down positional-awarness challenged bagsmashers and fuelers as they speed by in their vehicles. Think of them as kind of a "shear section" that protects the main structure of the wing from damage. This mostly holds true for CRJ's, but I imagine they could protect a Boeing or Airbus from the occasional run-in with a jetway. But seriously, I found out from the folks at Bombardier that the winglets on the new 700 series RJ have no aerodynamic benefits. Due to the fact the Challenger and CRJ have winglets, they added them on to the 700 for tradition's sake.
Thou shalt mind thine altitude,lest the ground reach up and smite thee.
Jet-Tech From , joined Dec 1969, posts, RR:
Reply 7, posted (14 years 1 month 1 day 14 hours ago) and read 1060 times:
Winglets reduce tip vortices, which reduce drag and thus fuel consumption. A lot of engineering goes into winglet design, they are not there just to look good. With the advances in computers, engineers can now use CFD programs in conjunction with CAD/CAM to design these highly complex curved airfoils. The benefits of retrofiting winglets on a "classic" are thus, including, in some cases, better MGTOW, climb, and cruise perf.
Amazin' what that funny looking winglet can do !