Who's Online

We have 1709 guests online

Live Traffic Feed

Life in the Skies

'A Local Bestseller!'

What Tony says
(See here)
and Book Launch video here
 
What others say

Les Posen
(See
here)

Yvonne Lee
(See
here)

Louisa Lim & Allan Koay
(See
here)

Aireen Omar, Asran & Bo Lingam
(See
here)

Get an autographed copy here

AMAZON.COM  -  To Order, please Click here 

(eBook) Kindle edition - please Click here

Latest Comment

What happens when a
The answer is found here in Tom, Dick or Harry htt

Malaysia Airlines -
I am interested in the 777 Super Ranger Flight of

How to unfreeze an A
Hello guys Thank you for this interesting topic.

Can an aircraft take
In pactical terms, a commercial airplane never tak

What are the eyesigh
Dear Capt Lim, I am hoping to join a flying schoo

How to unfreeze an A
Hi, following on from the clear discription above;

Should I get a Degre
hi capt lim..i am wilson from sarawak..i am 17 yea

How much does a Boei
Hello Captains and Co-pilots I am currently 14 yea

Why do I experience
I am 25 yr old male, have flown my entire life no

The MH 370 and MH 17
Hello i am wondering do you know or recomand some

Paperback Version

 For Local Availability - Check Here
 
Home > Flying on the Boeing 777 > Why are there no winglets on the Boeing 777?
Why are there no winglets on the Boeing 777?
Flying - Flying on the Boeing 777
Tuesday, 11 December 2007 20:37

Hello Capt Lim,

Why doesn't the Boeing 777 have winglets?

Razaq

Hi Razaq,

This topic is also covered in my previous FAQ and here are some more information extracted from an article by George Larson in the Air & Space Magazine.

Basically, winglets reduce wingtip vortices, the swirling airflows formed by the difference between the pressure on the upper surface of an airplane's wing and that on the lower surface. High pressure on the lower surface creates a natural airflow that makes its way to the wingtip and curls upward around it. When flow around the wingtips streams out behind the airplane, a vortex is formed. These twisters represent an energy loss and are strong enough to flip airplanes that fly into them.

Winglets produce a good performance boost for jets by reducing drag, and that reduction could translate into slightly higher cruising speed. The Boeing 747-400s have winglets. The Boeing Business Jet, a derivative of the Boeing 737, has a set of the firm's eight-foot winglets as well.

After the energy crisis in 1976, Richard Whitcomb, a NASA aerodynamicist, in a research, compared a wing with a winglet and the same wing with a simple extension to increase its span. As a basis for comparing both devices, the extension and the winglet were sized so that both put an equal structural load on the wing. Whitcomb showed that winglets reduced drag by about 20 percent.

A wing with high aspect ratio will provide longer range at a given cruise speed than a short, stubby wing because the longer wing is less affected by the energy lost to the wingtip vortex. But long wings are prone to flex and have to be strengthened, which adds weight. Winglets provide the effect of increased aspect ratio without extending the wingspan.

If winglets are so great, why don't all airplanes have them? In the case of the Boeing 777, an airplane with exceptionally long range, the wings grew so long that folding wingtips were offered to get into tight airport gates. Dave Akiyama, manager of aerodynamics engineering in Boeing product development, points out that designing winglets can be tricky because they have a tendency to flutter. And so the computer came up with a Boeing 777 wing design that did away the winglets and fly just as efficiently.

Trackback(0)

TrackBack URI for this entry

Comments (4)

Subscribe to this comment's feed
Mr
Hi Capt Lim.
What is the difference between the Boeing 777 and the Airbus A330?
I really want to get a career in commercial piloting but what aircraft in your opinion is better?
Thanks
Jordan.
Jordan , 06 Feb, 2009
Boeing 777 vs Airbus A330

Please read this posting here (http://www.askcaptainlim.com/i...&Itemid=39)
Captain Lim , 06 Feb, 2009
Good Answer but....
Hey Capt. Lim. I love your answer as posted above, but I noticed that you copyed that answer from a website. And you also forgot to quote where you found the answer....
Harry , 16 Jan, 2010
Why no winglets on the Boeing 777...
Hi Harry,

Yes, the answer was extracted from an article by George Larson in the Air & Space Magazine. This has been duly attributed to him in the answer above.

Captain Lim , 17 Jan, 2010

Write comment

smaller | bigger

busy
 

Paperback Version

 For Local Availability - Check Here

Recommended By..


LIFE IN THE SKIES

'A Local Bestseller!'

Recommended by

Patrick Smith
Boston USA
(See
here)

Capt Meryl Getline
ex-United Airlines USA
(See
here)

Capt Doug Morris
Canadian Airlines
(See
here)

Capt  Robert J Boser
ex-United Airlines USA
(See
here)

Get an autographed copy here

AMAZON.COM  -  To Order, please Click here 

(eBook) Kindle edition - please Click here

View Book Launch video here

Follow me

@CaptKHLim

Like What You Read?


If you like what you read, more stories are found in my book LIFE IN THE SKIES (Preview here) and you can purchase a copy here. To check for any latest updates or postings, you can follow my Twitter at @CaptKHLim or Facebook here

MH 370 Interviews

Click here to View

10 Most Popular Posts


30 Previous Posts


Disclaimer | Privacy
2004 - 2011 © AskCaptainLim.com | Site Concept by eQuilec.com