Why winglets

[Frix]

I have an interview coming up in the near future and a friend of mine was asked the following question:

Why doesn't the 777 have winglets.


It was after he was asked what the winglets do, and what the purpose was.

His answer to the first question was: To safe fuel. Installed on modern aircraft. (and a few other things).Then the interviewer said: "Why not on a 777 then".

Any inputs would be greatly appreciated

 

[liv'n_on_credit]

I don't know if this is the true answer or not, but this is from
this web site.

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

 

[TonyC]

I have an interview coming up in the near future and a friend of mine was asked the following question:

Why doesn't the 777 have winglets.

Was he interviewing to become a pilot, or an aeronautical engineer?

There are advantages of winglets that deal with airflow that improve the efficiency of the wing, and consequently reduce fuel required.

There are disadvantages of winglets that involve structural considerations. As previously mentioned, flutter is a real problem, so materials must be chosen carefully and the wing TIP itself must be rather rigid. (In the MD-11, fuel management contributes to wingtip rigidity, and once fuel quantity in the outboard tanks falls below a certain threshold, the wing is speed limited because of the winglets.)

Short of an interview with the Boeing design team, I think it might be impossible to determine exactly why the decision was made to exclude them on this wing. I can't believe a pilot interview would even require you know why. I imagine my answer would involve an explanation of the advantages and disadvantages of winglets, and conclude with a suggestion that the Boeing designers obviously determined that the disadvantages in this case outweighed the advantages.

And then I'd go home and wonder if I even wanted the job...

 

[mar]

Cathay Pacific mission specialist

This is a standard question for Cathay Pacific.

I interviewed with them Feb 2003 and I wrote up a two part "gouge" synopsis. You'll find it if you do a search under Cathay Pacific Intervew Gouge.

The 777 doesn't have winglets *but* it does have a 'raked' wing tip with the same result. It effectively increases span.

Other concepts you'll need to be familiar with are Deep Stall, Mach Tuck, Critical Mach numbers (Mcrit), Dutch Roll and High Bypass Turbine Engines.

You should have memorized every airframe variant in their fleet and why they choose the engines they did....

...modular construction (easy to work on) and inventory standardization.

Cathay Pacific is very proud of the fact they fly one of the youngest fleets in the world. They have a superior safety record despite going head to head with hurricanes every year. Their customer service is unequaled and consistently #1 or #2 in the industry.

You need to convince them that even though you're applying for a freighter position (with a North American basing) you have always dreamed of living in Hong Kong and flying international long haul. In fact, by definition, every flight out of Hong Kong is international but CX has recently picked up some China flying.

Familiarize yourself with the Swire Corp and the history of CX. It's all on their website.

Good luck.

 

[TonyC]

Re: Cathay Pacific mission specialist

This is a standard question for Cathay Pacific.

I interviewed with them Feb 2003 ...

I've got a quick question for you. IFALPA lifted the recruitng ban for Cathay Pacific on 5 June 2003. (IFALPA Lifts Cathay Pacific Pilot Recruitment Ban) Why were you interviewing with them 4 months earlier?

PRESS STATEMENT
IFALPA Lifts Cathay Pacific Pilot Recruitment Ban

Decision made at the request of the HKAOA in order to demonstrate its desire to forge a new working relationship with management

London - 5 June 2003 - Today, the International Federation of Air Line Pilots’ Associations (IFALPA) continued its support for the Hong Kong Aircrew Officers Association (HKAOA) by announcing that it has agreed to lift the recruitment ban on Cathay Pacific Airways and its subsidiaries.

The lifting of the recruitment ban was implemented following the HKAOA’s request. The ban was lifted as part of its continuing support for the HKAOA, and the union’s effort to demonstrate a genuine desire to remove all obstacles and resume dialogue with Cathay Pacific’s management, and ultimately resolve the ongoing industrial dispute between the two parties.

IFALPA issued the ban in July 2001 in response to Cathay Pacific management’s decision to sack 51 pilots, now dubbed The 49ers, without just cause or due process.

“The HKAOA requested that the ban be lifted to demonstrate a good-faith effort to forge a new working relationship with management,” said John Findlay, General Secretary of the HKAOA. “Now Cathay Pacific has absolutely no obstacles to delay the final resolution of one of the longest industrial disputes in aviation history.”

IFALPA President, Captain Dennis Dolan, concurred, “After careful consideration of the HKAOA’s request, IFALPA has lifted the ban against Cathay Pacific. We believe that the HKAOA’s request to lift the ban underscores the Association’s commitment to a new and mutually beneficial relationship with management.”

Captain Dolan emphasized that IFALPA remains hopeful that talks between Cathay Pacific and the HKAOA will produce positive results. “IFALPA, along with our 95 Member Associations around the world, will continue to monitor the labour situation in Hong Kong and at Cathay as part of our continued support for the HKAOA and all pilots worldwide.”

In March this year, the United Nations’ International Labour Organisation published an interim report following a request from IFALPA. The report was highly critical of the role of both Cathay Pacific and the Hong Kong Government, pointing to eroding employee rights in relation to the sackings and ongoing intimidation of union members.

 

[mar]

Lifelong aspirations of being a scab

Ah Tony. Can't we just live and let live? I thought we already agreed on that much.

I don't feel that I owe you or anyone else an explanation for my application and subsequent interview. Even more so due to the fact I was rejected from the interview process and never accepted employment.

But what the hell, it's a beautiful Saturday morning and I still have some coffee in my cup.

My initial application was April 2000. That was *before* the recruitment ban.

The position I applied for was a Second Officer postion.

CX sacked Capts and FOs. Not one SO was sacked. But SOs and FOs already employed by CX accepted upgrades to replace those pilots put on the street.

My employment as an SO wouldn't have replaced any pilot fired from CX.

Not only that but even if you believe it would be morally wrong to accept employment under a recruitment ban there is no way you can tell me that the simple act of interviewing would've been detrimental to the condition of current CX pilots.

The so-called union even admitted as much. Interviewing was fine; accepting an offer of employment was taboo.

There was no decision to be made until employment was offered.

And all the scab rhetoric was totally out of line. As I'm sure you know, it's illegal to strike in Hong Kong. No strike means no scabs. If the CX pilots had mustered the resolve to actually walk a picket line, risking all of their careers, then I would've been forced to further comtemplate my actions.

The fact of the matter is CX has their problems in terms of the pilot/management relationship but it's still a pretty good job.

I would've been proud to work there. I have a few friends there and I knew exactly what I was doing every step of the way.

Thanks for asking--as if any of it matters any more.

 

[TonyC]

Re: Lifelong aspirations of being a scab

Ah Tony. Can't we just live and let live? I thought we already agreed on that much.

Did I hit a nerve? I guess I better be careful with my grammar, spelling and punctuation here.

I don't feel that I owe you or anyone else an explanation for my application and subsequent interview. Even more so due to the fact I was rejected from the interview process and never accepted employment.

But what the hell, it's a beautiful Saturday morning and I still have some coffee in my cup.

Nope, you don't owe us anything. I only asked because of the appearance. I imagine there were, or will be, many more people who will make the same observation that I made that won't bother to ask the question and allow you the opportunity to explain. They'll just assume the worst.

I hope it's De-caf.

My initial application was April 2000. That was *before* the recruitment ban.

That's ample explanation for me - - I wish you had stopped there.

The position I applied for was a Second Officer postion.

CX sacked Capts and FOs. Not one SO was sacked. But SOs and FOs already employed by CX accepted upgrades to replace those pilots put on the street.

My employment as an SO wouldn't have replaced any pilot fired from CX.

Your employment in any crewmember postion [sic] during the recruitment ban would have been considered a violation. That rationalization doesn't hold water.

Not only that but even if you believe it would be morally wrong to accept employment under a recruitment ban there is no way you can tell me that the simple act of interviewing would've been detrimental to the condition of current CX pilots.

I do believe it would have been morally wrong to accept employment, and I agree that simply interviewing did not violate the recruitment ban (I don't think - - I haven't actually read the text of the ban.)

The so-called union even admitted as much. Interviewing was fine; accepting an offer of employment was taboo.

There was no decision to be made until employment was offered.

I wish you hadn't called the HKAOA a "so-called" union. What's that supposed to mean? That smacks of disrespect, mar.

And all the scab rhetoric was totally out of line. As I'm sure you know, it's illegal to strike in Hong Kong. No strike means no scabs. If the CX pilots had mustered the resolve to actually walk a picket line, risking all of their careers, then I would've been forced to further comtemplate my actions.

The fact of the matter is CX has their problems in terms of the pilot/management relationship but it's still a pretty good job.

Did I mention scab? Did I imply you were a scab or a scab wannabe? NO, I did not. But honestly, the more you talk, the more you have me thinking that you might have violated the recruitment ban had you been given a job offer.

When one accepts employment to replace those that have been wrongfully terminated, and when one does that in spite of the Collective Bargaining Agent's instruction to NOT do so, one becomes a scab. A picket line is not required - - and seat position is irrelevant.

I would've been proud to work there. I have a few friends there and I knew exactly what I was doing every step of the way.

Thanks for asking--as if any of it matters any more.

If it didn't matter, I wouldn't bother to ask. I'm glad to hear you managed to stay clean in spite of yourself. I'd hate to have to renege on that congratulatory beverage I owe ya.

 

[mar]

Yeah, you hit a nerve.

Your employment in any crewmember postion [sic] during the recruitment ban would have been considered a violation. That rationalization doesn't hold water.

Tony, with me, what you see is what you get. I shoot real straight. Before I make a decision I consider every angle and then go for a second and third opinion just to be sure.

What I'm trying to say is, though I may not be perfect I'm rather analytical and yes I would've accepted employment at CX if it were offered at that time.

I had already made that decision before I went to the interview.

Now. Maybe you consider the quote above to be rationalization and you think I was disrespectful to call the HKAOA a so-called union. But what sort of union allows thier own members to upgrade to replace pilots that were fired? What sort of union punishes new hire pilots and rewards their own after management overtly and unabashedly singles out 50 pilots?

I closely followed events at CX between April 2000 and my interview. I feel the HKAOA had some valid concerns.

There was (and may still be) outright harassment by management. But I'll tell you what, when you accept employment in a "Special Administrative Region" you have to ask yourself, Why did western managers choose to do business here?

Could it be they found the regulatory environment to be in their favor?

And wouldn't you consider it just a little naive to accept employment at such a company and *still* expect all of the convenient recourses a worker in Britain, America, Australia and Canada enjoys?

And here lies the crux of the matter. When you look to the left of this post and read the short list of aircraft that got me to this point in my career a lot of people may sigh wistfully and think quaint thoughts of flying mail to eskimo villages.

They never consider the dirty work involved. They don't see the falsified logbooks. The falsified training. All of the pencil whipping. They don't consider what it's like to fly an airplane all day with one brake on narrow gravel strips with crosswinds and patchy ice. They don't know what it's like to navigate a single engine airplane in darkness at 500 agl for 130 miles the whole time not knowing what the visibility is, not that it matters because when you get over the waypoint you'll either see the runway lights or not. They don't know about the utter reject from normal society who is your boss and can't seem to get his mind out of the good-old-days when a pilot "just got the job done without complaining." They don't see the institutionalized dysfunction between the FAA and the local operators. They don't see the accident, incident and/or violation on my record. They don't know that in fact I consider myself living on borrowed time because to be perfectly honest I'm not sure how I survived this long. You may consider that melodramatic but here's a suggestion:

You keep that congratulatory beverage the next time I'm in ANC and let *me* buy the beer. I'll tell you even more stories about flying in the bush and why an SO job at CX would've been a dream come true.

I'm truly sorry CX didn't see SO material in me because I have nine years of proving that I can work a miserable job and get it done without complaining.

I would've been (and am) a fantastic employee.

And, just for the record, yeah, I knew what I was getting into when I moved to Alaska. Just like I would've known about Hong Kong.

My friends say, "Once an ex-pat, always an ex-pat."

I say, "Once a bush pilot, always a bush pilot."

Same difference. It's just a state of mind. And you're either good at it or not.

 

[banned username 2]

Can we PLEASE get back to the "Winglet" discussion, it was much more interesting... and if not Winglets, how about some BBQ...?

 

[Gillegan]

OK, back to winglets. Wing tip vortices are created from the high pressure air on the bottom of the wing (in the vicinity of the wing tip) flowing to the lower pressure area on the top of the wing with a resultant loss of lift and wing efficiency. If you look closely at a winglet, it is actually canted out somewhat and is at a slightly negative angle of attack in relation to the rest of the wing. The wingtip vortex acts on the back of the winglet and due to the geometry of the whole arrangement, actually creates some positive thrust on the winglet. When you add up all of the aerodynamic forces on the airplane, it shows up as a reduction in drag. As stated earlier, this is not without some cost, namely the increased weight of the structure. As all wings are not created equal, the benefits are outweighed by the costs for some aircraft.

Another way of reducing the loss of wing efficiency from wingtip vortices is to carefully tailor the lift profile of the wing to reduce the spanwise flow in the area of the wingtip. I assume that Boeing has done this with the B777. Hope this helps.

 

[justApilot]

Years ago Delta had a 727 with winglets. I think they flew that thing around for a year or so collecting data on the fuel burns. At the end of the year the winglets were removed. I guess the cost advantage in fuel burn was less than what it cost to install them.

I flew Westwinds with and without those things. It made no difference in the fuel burns, at least that was my experience. Those with the winglets were no fun to fly at 410...kinda did a dutch roll thing.

 

[TonyC]

Re: Yeah, you hit a nerve.

You keep that congratulatory beverage the next time I'm in ANC and let *me* buy the beer.

No, I won't renege on my offer just because I think you would have made a mistake. We can exchange thoughts on the matter and still be civil, right?

They also say "once a scab, always a scab." I'm glad you're not one.

 

[mar]

Back on topic? Sure why not?

Can we PLEASE get back to the "Winglet" discussion, it was much more interesting... and if not Winglets, how about some BBQ...?

See, here's the deal: I already answered the gentleman's question. The 777 has raked wingtips. That was an answer no one else had offered.

Somehow I feel like I should apologize for derailing a thread where I provided the correct answer and offered more than a little insight into the company in question.

Whatever. It has always amazed me when the moderators decide to begin moderating.

Tony. Ok man. It's a deal. But apparently the scab thing has gone unregistered.

 

[another747]

A slight correction, only the new series 777's have "raked" wingtips. The older 200's and 300's do not.

 

[banned username 2]

Re: Back on topic? Sure why not?

Whatever. It has always amazed me when the moderators decide to begin moderating.

OK, first you guys cry we don't do enough, then you cry we do too much... Which is it going to be???

I didn't post as a moderator, just as someone who thought this thread could go in a better, more constructive direction... If I really wanted to "moderate" I would have just deleted the unrelated posts... (which I didn't)

 

[GVFlyer]

Winglets

Winglets not only reduce wingtip vortices, but also increase the effective span of the wing by approximately 1/3 the height of the winglet. In the case of the GV and derivitives, they also provide a forward thrust vector. Gulfstreams may be MEL'd to fly without a winglet, but range must be reduced by 7%.

Besides that, they look cool and marketing loves them.

The winglets for the BBJ were developed by Joe Clark and Aviation Partners, the same group of former Boeing engineers that got their start doing aftermarket winglets for the G-II.

GV

 

[Hugh Jorgan]

Why not winglets?

 

[banned username 2]

Re: Winglets

Besides that, they look cool and marketing loves them.

The G-V's winglets are much nicer looking than the G-IV...

 

[av8orboy]

winglets

Folding tips???? Just a guess..

 

[crudeoilpilot]

Winglets have also been coined as Flight Engineer tombstones on the (re-engineered) wide-body aircraft. Personally speaking, I dont care for that one.