cowl Flaps and Winglets

[atotti2000]

wat do they do?

[Craig.]

winglets are used to stop the flow of air running off the tips of the wings which creates more drag and effectivly makes the wings less efficient. or at least i believe thats correct.

[Nexus]

Cowl flaps, are doors that regulates the cooling of the engine (not used on modern jets)
When more cooling air is needed you'll open the cowl flaps  :)

Winglets are - like Craig said - drag reducing, thus also fuel saving.
But the winglets also increase the overall spread of the trailing egde vortices, creating more lift at the wingtips.

Quoted from Boeing Aero Magazine

"* Creates more efficient flight characteristics in cruise and during take off and landing
* Approx 4% increase in range (130nm for the 737-800)but you must be at LRC or OPT altitude"

LRC stands for Long Range Cruise and is available in the FMC's CRZ page.

As you can see, winglets are no use for short flights.

[atotti2000]

Thanks guys. i knew they were there, just didnt know what to do with them

thankyou:D

[Ivan]

Cowl flaps have another funcrtion, depending on the contrruction...

Keeping the snow out of the engine cowling (Li-2, Il-12/14)

[Skligmund]

Winglets are actually efficient enough that they work as well as extending the wings the same lenght as the winglet itself. Really neat trick.

[beaky]

Yeah, I've heard of this: Vertical wing surfaces do in fact provide some lift. Which will of course create drag, so... ouch.
 Flying airplanes is definitely more fun than designing them...  ;D