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Logic In Not Ordering Winglets On Brand New Planes  
User currently offlineAviationAddict From United States of America, joined Feb 2006, 630 posts, RR: 0
Posted (7 years 8 months 1 week 10 hours ago) and read 3111 times:
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What are some of the reasons why airlines would order brand new airlines sans winglets with all the range and efficiency benefits the winglets have proven to offer? As an example, I've noticed that the new 73GERs for ANA are not equipped with the winglets; why? Is it generally a cost issue?

8 replies: All unread, jump to last
 
User currently offlineCurmudgeon From Australia, joined Oct 2006, 695 posts, RR: 22
Reply 1, posted (7 years 8 months 1 week 10 hours ago) and read 3097 times:

It is mostly a cost trade-off, but its not the only reason. Winglets are only beneficial over longer distances (say two to three hour flights). They add some weight, and it takes a lot of miles at the very slightly improved drag profile to pay for them. ANA would not have a route network long enough to warrant the winglets. While I don't know this for a fact, I expect that a used aircraft buyer could have them retrofitted if needed.

Cur...



Jets are for kids
User currently offlineIkramerica From United States of America, joined May 2005, 21582 posts, RR: 59
Reply 2, posted (7 years 8 months 1 week 10 hours ago) and read 3072 times:

There might also be a benefit to ordering the plane, then the winglets and installing them yourself. I've read that it can be cheaper depending on your contract. IIRC, CO installs winglets themselves even on brand new 737NG aircraft. Maybe a CO mechanic can confirm or refute that.

Quoting Curmudgeon (Reply 1):
It is mostly a cost trade-off, but its not the only reason. Winglets are only beneficial over longer distances (say two to three hour flights).

That is not true. It's a myth perpetuated on a.net. Fuel burn really comes into play on longer flights, but that's not the only factor.

There are very real benefits on any flight, including approach speed, climb performance, field length, etc.

BUT, if you don't NEED those benefits (a 73G out of NRT or KIX doesn't need any help), then that's part of the decision.



Of all the things to worry about... the Wookie has no pants.
User currently offlineERAUgrad02 From United States of America, joined Nov 2005, 1227 posts, RR: 0
Reply 3, posted (7 years 8 months 1 week 9 hours ago) and read 3006 times:

Um it di get winglets. why get an -ER if you are flying the distance to warrant it? Winglets are standard. the 1st flight was without but were added later.


Desmond MacRae in ILM
User currently offlineCurmudgeon From Australia, joined Oct 2006, 695 posts, RR: 22
Reply 4, posted (7 years 8 months 1 week 9 hours ago) and read 2978 times:

Quoting Ikramerica (Reply 2):
That is not true. It's a myth perpetuated on a.net. Fuel burn really comes into play on longer flights, but that's not the only factor.

Gee, I don't know about that. I was told that by the local Boeing rep long before I ever heard of A.Net.

I'd like to see a comparison of field length limits and approach speeds between the two variants before I comment further.

At my airline, the performance engineers maintain that the winglets cost 1% more for the first two hours, then start paying back the fuel so that they save over a three hour flight. How sophisticated an algorithm they employ for this calculation wasn't revealed.

My airline's management went on record stating that over our route network the winglets were a wash, economy wise. The deciding factor (as explained by the CEO, live) was that they looked way cool, and customer surveys showed that the travelling public perceived winglet equipped planes as "new" and "modern", whereas the non-winglet versions didn't return any positive response from those surveyed. Also, our competitor had them, which makes those thorny decisions easy to justify in retrospect.



Jets are for kids
User currently offline2H4 From United States of America, joined Oct 2004, 8956 posts, RR: 60
Reply 5, posted (7 years 8 months 1 week 9 hours ago) and read 2953 times:
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Quoting Curmudgeon (Reply 4):
I'd like to see a comparison of field length limits and approach speeds between the two variants before I comment further.

Here's some very basic info from Aviation Partners Boeing:


IMPROVED TAKEOFF PERFORMANCE
By allowing a steeper climb, winglets pay off in better takeoff performance, especially from obstacle-limited, high, hot, weight-limited, and/or noise-restricted airports. Performance Improved climb gradients increase 737-800 allowable takeoff weight (TOW).Some examples include: Chicago-Midway: ~1,600 lb additional TOW Lanzarote (Canary Islands): ~3,500 lb additional TOW Albuquerque, Denver, and Salt Lake City: ~4,400 lb additional TOW


REDUCED ENGINE MAINTENANCE COSTS
Better climb performance also allows lower thrust settings, thus extending engine life and reducing maintenance costs. Lower Required Thrust Levels Extend On-Wing Life Takeoff - Winglets allow up to 3% incremental derate. Cruise - Cruise thrust levels are reduced by up to 4%.


IMPROVED OPERATIONAL FLEXIBILITY
By increasing Payload Range and Overall Performance, Blended Winglets add flexibility to fleet operations and route selection. Air Berlin notes, "Previously, we'd step-climb from 35,000 to 41,000 feet. With Blended Winglets, we can now climb direct to 41,000 feet where traffic congestion is much less and we can take advantage of direct routings and shortcuts which we could not otherwise consider."


2H4





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User currently offlineIkramerica From United States of America, joined May 2005, 21582 posts, RR: 59
Reply 6, posted (7 years 8 months 1 week 9 hours ago) and read 2889 times:

Quoting 2H4 (Reply 5):
2H4

Exactly. The information is not exactly hard to find.

The a.net myth I am referring to is not that efficiency doesn't improve on long trips or that on very short trips it can be slightly hurt (fuel burn only).

The MYTH is that it's the only reason to install them!

They can increase payload, require lower thrust for takeoff, allow for steeper climb angle which means less restrictions out of a place like BUR, and other short runway airports, high airports or airports with obstacles. They can also increase range, decrease approach speed, etc.. There is a tradeoff in that you can't have ALL of the benefits on the same trip, of course. But it adds flexibility to the aircraft.

If fuel burn were the only value, and it only really made a difference on long flights, and otherwise it was just dead weight, WN would not have moved to a whole fleet winglet approach, since the vast majority of their routes are too short to "benefit" or a wash, yet WN is supposed to be one of the most well run airlines in the world.

So, logic alone would indicate there is more to a winglet on a 737NG than economy on a long flight, if WN is sold on them.

Quoting Curmudgeon (Reply 4):
I was told that by the local Boeing rep long before I ever heard of A.Net.

Then either he was not informed, or you misunderstood what he was saying. He was likely saying that the FUEL BURN benefit only really goes positive on longer flights. This does not mean he said "there's no value on shorter legs."

But you made that claim...

Quoting Curmudgeon (Reply 1):
Winglets are only beneficial over longer distances (say two to three hour flights).

And THAT is the a.net myth.

Have a nice day.



Of all the things to worry about... the Wookie has no pants.
User currently offlineCurmudgeon From Australia, joined Oct 2006, 695 posts, RR: 22
Reply 7, posted (7 years 8 months 1 week 9 hours ago) and read 2884 times:

Quoting 2H4 (Reply 5):
Here's some very basic info from Aviation Partners Boeing:


IMPROVED TAKEOFF PERFORMANCE
By allowing a steeper climb, winglets pay off in better takeoff performance, especially from obstacle-limited, high, hot, weight-limited, and/or noise-restricted airports. Performance Improved climb gradients increase 737-800 allowable takeoff weight (TOW).Some examples include: Chicago-Midway: ~1,600 lb additional TOW Lanzarote (Canary Islands): ~3,500 lb additional TOW Albuquerque, Denver, and Salt Lake City: ~4,400 lb additional TOW

The airport would have to be remarkably marginal for winglets to make a difference like that, and the sector length would have to be long enough so that max landing weight wasn't the limiting factor. I'd like to see the raw data to compare...sounds to me like they were using some pretty high temperatures. Still, impressive numbers which are a whole order of magnitude larger than I'd have thought. Good thing the 737's not a triplane: it would have to be tethered to the ground.

Quoting 2H4 (Reply 5):
REDUCED ENGINE MAINTENANCE COSTS
Better climb performance also allows lower thrust settings, thus extending engine life and reducing maintenance costs. Lower Required Thrust Levels Extend On-Wing Life Takeoff - Winglets allow up to 3% incremental derate. Cruise - Cruise thrust levels are reduced by up to 4%.

This is the same claim restated . Any time something gives you better field performance you can trade it off for lower T/O thrust, or a bit of both. The cruise savings of "up to" 4% would be best case max range savings.

Quoting 2H4 (Reply 5):
IMPROVED OPERATIONAL FLEXIBILITY
By increasing Payload Range and Overall Performance, Blended Winglets add flexibility to fleet operations and route selection. Air Berlin notes, "Previously, we'd step-climb from 35,000 to 41,000 feet. With Blended Winglets, we can now climb direct to 41,000 feet where traffic congestion is much less and we can take advantage of direct routings and shortcuts which we could not otherwise consider."

Winglets or not, any time you can climb directly to FL410 you are pretty light. It takes about 28 minutes real world time to climb directly to FL410, and another 24 minutes to descend. In Air Berlin's case, I'd guess that getting above the crowd in European airspace would have a big advantage, but again this argument assumes a longish sector length. The 73H is not the nicest thing to fly at high (or any) levels...I can't say what the 738 would be like.



Jets are for kids
User currently offline2H4 From United States of America, joined Oct 2004, 8956 posts, RR: 60
Reply 8, posted (7 years 8 months 1 week 9 hours ago) and read 2861 times:
AIRLINERS.NET CREW
DATABASE EDITOR



In allowing for reduced takeoff thrust settings, I believe winglets would also provide a lower noise signature.

Quoting Curmudgeon (Reply 7):
Good thing the 737's not a triplane: it would have to be tethered to the ground.

 rotfl 


2H4





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