Hey blog, first off I would like to appologize for the delay in posting a blog. Now to the meat of the blog. So two weekends ago I flew to Cincinati with my girlfriend and on the flight up had a question pop into my head. I was flying on one of the smaller regional jets an Embraer 170 and I was next to the wing. What I noticeced on this plane and I have noticed on other smaller planes before it the 90 degree turn of the wing right at the end.
My question for all of you is why do we find this turn up in the wings? Is its just to look cool or does it actually serve a purpose?
I know that wing tips do serve a purpose and improve efficiency of fixed wing aircraft. They direct the airflow over the wingtip in such a way that reduces drag over the wing. My question is how exactly does it reduce drag?
ReplyDeleteThe turn up in the wing is to reduce the amount of drag produced by the wingtip vorticies. This allows a greater increase in lift and allow for less fuel burn in flight. In some cases it allows up to 10% less fuel being burned, allowing some flights to be made possible with the extra range (therefore making more money).
ReplyDeleteMy question to you is what the major factor in determining if you put a winglet, wingtip fence, or "blended winglet" like you see on the 777?
-Jason
The tip of the wing being shaped like that is ment to reduce drag and increase lift. I also found something online that says they decrease wake-turbency for aircrafts flying behind them. I dont know how they would do this though?
ReplyDelete-Eric Siegfried
Ahh, the beautiful and useful winglet- one of my favorite mysteries on an airplane! I’ll do my best to answer your question Von Hayes! Anyway, winglets, as I said, are incredibly useful. Their purpose, as others have correctly answered, is to ultimately decrease drag and increase profits! However, to understand what they do, I need to explain how “lift” and “drag” are created. As an airplane is flying through the air, the air flow that “strikes” the leading edge of the wing is called the “relative wind.” The relative wind it then “split” so that some goes over the top and some goes under the wing. When this happens, we learned from Bernoulli’s Principle that if a liquid (in our case air) is accelerated, the static pressure DECREASES. If you look at the side profile of a wing, you’ll notice that the top surface is slightly curved or humped and the bottom of the wing is essentially flat. When the relative wind strikes the leading edge, the portion that goes over the top has to “travel” a further distance than the air that travels under the wing, lowering the pressure on the top. We know that pressures want to move from high to low, so with the difference in pressures the airplane lifts off the ground! Now, surprisingly, air doesn’t move directly from the leading edge to the trailing edge- it actually moves OUTWARD while travelling across the wing (i.e. away from the fuselage toward the wing tip). This is where winglets come into play… as the air is moving outward along the wing, when it reaches the wingtip on an airplane WITHOUT winglets, the high pressure air underneath the wing wraps UP and AROUND the wingtip, “mixing” with the low pressure air coming off of the top of the wing, creating a vortex! What a winglet essentially does it creates a longer surface (the length from the bottom of the winglet to the top) that the high pressure air has to travel. At the same time, the lower pressure air on top of the wing moves “up” and along the inside of the winglet. With the combined smaller surface area and the longer distance the air has to move before it is “mixed,” it greatly reduces the strength of the vortex that is generated from the production of lift. (Was that long enough, or what?!)
ReplyDeleteAnd, I do think they look cool too =)
ReplyDeleteof course it serves a purpose on the aircraft, and most likely it helps aircraft be more stable in turns. Im just not sure how its actually working>?
ReplyDeletePETER LITVINKO