All about Winglets

Winglets are also available for Classics. The first winglet equipped 737-300 flew in Nov 2002 and gained its FAA supplemental type certificate (STC) on 30 May 2003. Winglet equipped Classics are known as Special Performance (SP). Winglets have the potential to give the following benefits: Improved climb gradient. This will enable a higher RTOW from climb limited airports (hot, high or noise abatement) or obstacle limited runways. Reduced climb thrust. A winglet equipped aircraft can typically take a 3% derate over the non-winglet equivalent aircraft. This can extend engine life and reduce maintenance costs. Environmentally friendly. The derate, if taken, will reduce the noise footprint by 6.5% and NOx emissions by 5%. This could give savings on airport noise quotas or fines. Reduced cruise thrust. Cruise fuel flow is reduced by up to 6% giving savings in fuel costs and increasing range. Improved cruise performance. Winglets can allow aircraft to reach higher levels sooner. 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.” Good looks. Winglets bring a modern look and feel to aircraft, and improve customers' perceptions of the airline. If winglets are so good, you may wonder why all 737s don’t have them. In fact 85% of all new 737s are now built with winglets, particularly the 800 and 900 series and of course all BBJs. It comes down to cost versus benefits. Winglets cost about $725,000USD and take about 1 week to install which costs an extra $25-80,000USD. Once fitted, they add 170-235kg (375-518lbs) to the weight of the aircraft, depending upon whether they were installed at production or a retrofit. The fuel cost of carrying this extra weight will take some flying time each sector to recover, although this is offset by the need to carry less fuel because of the increased range. In simple terms, if your average sector length is short (less than one hour) you wont get much the benefit from winglets - unless you need any of the other benefits such as reduced noise or you regularly operate from obstacle limited runways. There is a small difference in rotation rate for aircraft with winglets installed and, as a result, the crew needs to be cautious of pitch rate. There is approximately a ½ unit take-off trim change between non-winglet and winglet aircraft so the green band is slightly different for winglet aircraft. Finally, the dry “maximum demonstrated” crosswind limit is slightly reduced with winglets to 34kts. According to APB this is because “the FAA will only let us document the max winds experienced during flight test... so if we had been able to find more crosswind, then the 33kts might have been more. There appears to be no weather cocking effect due to winglets.”   Other winglet News Stories An excellent article by Boeing in Aero 17 is available at: http://www.boeing.com/commercial/aeromagazine/aero_17/winglet_story.html

Next-Generation 737 Production Winglets Description Winglets are wing tip extensions which provide several benefits to airplane operators. The winglet option increases the Next-Generation 737's lead as the newest and most technologically advanced airplane in its class. These new technology winglets are now available on 737-800s as well as on the Boeing Business Jet (737-700 and 737-800). There are two types of winglet available, Boeing's own built into the wing at the time of manufacture and the APB winglet as a retrofit.

Benefits Depending on the airplane, its cargo, the airline's routes and other factors, winglets have the potential to give: 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%. FUEL SAVINGS Winglets lower drag and improve aerodynamic efficiency, thus reducing fuel burn. Depending on the missions you fly, blended winglets can improve cruise fuel mileage up to 6 percent, especially important during a time of rising fuel prices. INCREASED PAYLOAD RANGE The addition of Aviation Partners Blended Winglets to the 737 Next Generation has demonstrated drag reduction in the 5 to 7% range that measurably increases range and fuel efficiency . In addition, the Blended Winglets allow the 737-NG to take off from higher, hotter airports with increased payload. Series Range (nm) Normal Range (nm) With Winglets -700 3250 3634 -800 2930 3060 -900 2670 2725 ENVIRONMENTALLY FRIENDLY With winglets, you can be a good neighbour in the community you serve. They enhance performance at noise-restricted airports and cut the affected area by 6.5 percent, saving you money on airport noise quotas or fines. By reducing fuel consumption, winglets help lower NOx emissions by 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." MODERN DRAMATIC APPEARANCE Blended Winglets bring a modern look and feel to aircraft, and improve customers' perceptions of the reliability and modernity of the Airline.

Dimensions Each winglet is 8 feet long and 4 feet in width at the base, narrowing to approximately two feet at the tip. Added wingspan Winglets add approximately 5 feet to the airplane's total wingspan - from 112 feet 7 inches to 117 feet 2 inches. (All Next-Generation 737 models have the same wingspan.) Weight Each winglet weighs about 132 pounds. Increased weight to the airplane for modifying wing and installing winglets is about 480 pounds. Airplane provisions Structural modifications to accommodate the winglet include strengthening the wing's centre section and other internal strengthening on the wing. These enhancements are done in the normal production process. Various systems changes have also been made to accommodate winglet installation. Offerability Production and retrofit winglets for the Next-Generation 737s are available through Boeing (production) and Aviation Partners Boeing (retrofit). Aviation Partners Boeing (APB) is a joint venture partnership between Boeing and Aviation Partners Inc. (API). Certification Retrofit FAA Supplemental Type Certificate (STC) was granted to APB on 3/23/2001. LBA (German regulatory agency) STC was granted to APB on 5/4/2001. JAA STC was granted May 2001. Boeing PLOD (program letter of definition) was granted 5/9/2001 by both the FAA and JAA for Boeing production. Availability 737-700, 737-800, 737-900, 737-BBJ - available now. Deliveries began May 2001. Initial customers included: South African Airways, Air Berlin, American Trans Air, Polynesian Airlines, and Hainan Airlines - both through direct purchase and leasing options via ILF, GATX, GE Capital Corp., and Flightlease. Operational Considerations There is a small difference in rotation rate for airplanes with winglets installed and, as a result, the crew needs to be cautious of pitch rate. There is also approximately a ½ unit take-off trim change between non-winglet and winglet aircraft so the green band is slightly different for winglet aircraft. 737-200 Mini-Winglets   This is a 737-200Adv, L/N 628, fitted with mini-winglets. This is part of the Quiet Wing Corp flap modification kit which gained its FAA certification in 2005. The package includes drooping the TE flaps by 4 degrees and the ailerons by 1 degree to increase to camber of the wing. Benefits include: Payload Increase of up to 5,000 lbs. Range Increase up to 3% Fuel Savings up to 3% Improved Takeoff/Landing Climb Gradients Reduced Takeoff/Landing Field Length Improved High Altitude Takeoff/Landing Capability Improved Hot Climate Performance Reduced Stall Speeds by 4-5kts Photo: Julian Whitelaw 737 MAX Advanced Technology (AT) Winglets Boeing has now developed, built and will be installing their own winglets for the 737 MAX family. The "Advanced Technology" winglet combines rake tip technology with a dual feather winglet concept into one advanced treatment for the wings of the 737 MAX.". The AT Winglets measure 8 feet from root to top of winglet and a total of 9 feet 7 inches from bottom of lower tip to top of higher tip. The top portion is 8 feet 3 inches and the bottom portion is 4 feet 5.8 inches. The ground clearance of the bottom tip is 10 feet 2 inches. Boeing claim they will give 1.5% fuel burn improvement over current technology winglets. They explain this as follows:"The AT winglet further redistributes the spanwise loading, increasing the effective span of the wing. The AT winglet balances the effective span increase uniquely between the upper and lower parts and therefore generates more lift and reduces drag. This makes the system more efficient without adding more weight." This graphic from Boeing shows from top to bottom, a non-winglet aircraft, a current blended winglet and an AT winglet. The AT winglet has a more even lift profile across its span.

News Stories

11 Aug 2012 - Boeing Designs Advanced Technology Winglet for 737 MAX Aviation Partners has started showing airlines a split-tip winglet with blended, "scimitar"-edged feathers as a retrofit option that the joint venture estimates can reduce fuel consumption by 2.5 to 3% on next-generation 737s. The move precedes a launch decision by the board of directors of the Aviation Partners Boeing (APB) joint venture, but that approval should come "shortly", says Joe Clark, founder of Aviation Partners, the Seattle-based firm that designed the standard blended winglet ordered on more than 4,600 737NGs. Aviation Partners unveiled the scimitar-edged winglet last October and launched flight tests on a 737 Boeing Business Jet in April, which confirmed the estimates of computational fluid dynamics models to within one-tenth of a percentage point, Clark says. "We are very pleased with what we've achieved," he adds. While APB prepares to offer a scimitar-edged split-tip winglet on the 737NG, Boeing is readying a straight-edged split-tip winglet on the 737 Max. Both companies claim to have arrived on the split-tip configuration for the 737 at nearly the same time by coincidence. Aviation Partners had no prior knowledge of Boeing's "dual-feather" split-tip winglet for the 737 Max, and has received no information on the design from its joint venture partner, Clark says. For its part, Boeing also was unaware of the Aviation Partners design when it began working on the Advanced Technology (AT) winglet around June 2011, says Robb Gregg, a chief aerodynamicist for the 737 Max. "As I was looking at the configuration, we needed to get more performance out of it and really the only place we hadn't spent a lot of time was looking at the [wing]-tip," Gregg says. Boeing completed trade studies between August and September last year, he says, then fabricated a set of optimal shapes for testing in a wind tunnel. Although the split-tip design appears to be a new innovation, it traces back to Robb's previous work as a chief aerodynamicist at McDonnell Douglas. The airframer that merged with Boeing in 1997 had pioneered the installation of winglets on airliners in the mid-1980s. The MD-11 entered service with an up/down winglet, with a shortened lower surface forward of the upper surface. The lower surface was shaped to improve stall characteristics at low-speed, Gregg says. McDonnell Douglas also proposed a split-tip winglet for the short-lived MD-12, a late-1980s concept for a four-engined double-decker. As the chief aerodynamicist of the MD-12 concept, Gregg says, he proposed the split-tip to optimize lift of a wingspan artificially constrained to a length of 64.9m (213ft) to fit into existing airport gates. Likewise, the 737 Max also demanded more performance than a blended winglet could produce. "Because we needed more performance to satisfy the customers we felt we needed to push the technology a bit further," Gregg says. A split-tip wingtip has never been tested in flight test, and Boeing currently has no plans to test the 737 Max AT Winglet on a surrogate platform. Boeing is confident that computational fluid dynamics models have predicted drag characteristics accurately, Gregg says. At the same time, Boeing is not convinced a split-tip winglet will produce performance improvements as a retrofit option on the 737NG, although it has not conducted an analysis yet. Holding Boeing back is the knowledge that the AT Winglet increases the aerodynamic loads on the outboard wing section. "The better the winglet the more load it's going to drive outboard. Otherwise it didn't do anything for you," Michael Teal, chief project engineer on the 737 Max, said in a July interview. "The question is how difficult it would be to retrofit," he added. "You're getting out there on the end of a wing; it's not that thick. It's not something that's easy to take apart and add gauge to." Despite being joint-venture partners, Boeing and Aviation Partners also have different views on the margin of benefit provided by a split-tip winglet. Boeing predicts the straight-edged split-tip on the 737 Max will contribute 1.5% to fuel burn reduction. Aviation Partners, on the other hand, is proposing a 2.5% to 3% benefit from installing the scimitar-edged winglet on the 737NG, which shares the same airfoil as the 737 Max. Even so, Aviation Partners is optimistic that scimitar-edged split wing-tips will be retrofitted on as much as 60% of the 737NG fleet, Clark says. 2 May 2012 - Boeing Designs Advanced Technology Winglet for 737 MAX RENTON, Wash., May 2, 2012 Boeing announced today a new winglet design concept for the 737 MAX. The new Advanced Technology winglet will provide MAX customers with up to an additional 1.5 percent fuel-burn improvement, depending on range, on top of the 10-12 percent improvement already offered on the new-engine variant. "The Advanced Technology winglet demonstrates Boeing's continued drive to improve fuel burn and the corresponding value to the customer. With this technology and others being built into the MAX, we will extend our leadership," said Jim Albaugh, president and CEO, Boeing Commercial Airplanes. "Incorporating this advanced technology into the 737 MAX design will give our customers even more advantage in today's volatile fuel price environment." Compared to today's wingtip technology, which provides up to a 4 percent fuel-burn advantage at long ranges, the Advanced Technology winglet provides a total fuel-burn improvement of up to 5.5 percent on the same long routes. "The concept is more efficient than any other wingtip device in the single-aisle market because the effective wing span increase is uniquely balanced between the upper and lower parts of the winglet," said Michael Teal, chief project engineer, 737 MAX. Boeing aerodynamicists used advanced computational fluid dynamics to combine rake tip technology with a dual feather winglet concept into one advanced treatment for the wings of the 737 MAX. The Advanced Technology winglet fits within today's airport gate constraints while providing more effective span thereby reducing drag. Ongoing 737 MAX testing in the wind tunnel validated the new concept on the airplane. The super-efficient design has been incorporated into the 737 MAX design and production system plans. "We have assessed the risk and understand how to leverage this new technology on the MAX within our current schedule," said Teal. "This puts us on track to deliver substantial additional fuel savings to our customers in 2017." Airlines operating the 737 MAX now will gain an 18 percent fuel-burn per-seat improvement over today's A320. Depending on the range of the mission, MAX operators will realize even more savings. "Adding the Advanced Technology winglet to the 737 MAX is consistent with our demonstrated performance on delivering increasing value to our customers, on time, throughout the life of the 737 program," said Beverly Wyse, vice president and general manger, 737 program. To date, the 737 MAX has more than 1,000 orders and commitments from 16 customers worldwide. 30 Apr 2007 - APB selects UK supplier as it launches 767-300ER programme with American order UK-based GKN Aerospace has been selected by Aviation Partners Boeing (APB) as a new supplier of the US company's blended winglets for the rapidly expanding Boeing 737 "Classic" and newly launched 767 retrofit programmes, while United Airlines is poised to start retrofitting its 757s. The aerostructures specialist joins APB winglet supplier Kawasaki Heavy Industries. Winglets for the 737 Next Generation. Despite the much-needed addition of GKN, APB says the 737 Classic retrofit line is sold out through 2009 at the rate of six shipsets a month. "We're still going to ramp up as fast as we can, but it will be the end of this year or early next before they can begin providing the first parts," says APB vice-president sales Patrick LaMoria.  26 Dec 2006 - Aviation Partners Boeing Launches 737-900 Blended Winglet Program With program launch of Aviation Partners Boeing 737-900 Blended Winglets, and first deliveries slated for December 2007, the world's airways will soon be making room for even more Blended Winglet Performance Enhanced airplanes. Launch customers Continental Airlines, KLM and Alaska Airlines plan to complete the retrofit of their 737- 900s by the end of the first quarter of 2008. "We've had a great deal of customer interest in 737-900 Blended Winglets and this important new program gives more of our operators commonality and the ability to fly with 100% Blended Winglet equipped 737NG fleets," says Aviation Partners Boeing CEO John Reimers. "This program is off to a very strong start and we anticipate that the remaining handful of operators of the 737-900 will be unable to ignore the tremendous value Blended Winglets add to the aircraft." Benefits of Aviation Partners Boeing's Visible Technology are nothing short of dramatic in fuel savings, improved performance and environmental advantages. Given average aircraft utilization rates, operators will save over 100,000 gallons (380,000 liters) of fuel per aircraft per year resulting in a payback on investment of less than 3 years. Noise footprint, on takeoff and landing, is reduced by an average of 6.5% while engine emissions of carbon dioxide and nitrous oxides are lowered on the order of 5.0%. "Blended Winglets will give KLM improved range and payload on many longer stage lengths in its European Network," says KLM's Vice President of Fleet Services Rene Kalmann. "Further this decision fits in KLM's Corporate Social Responsibility policy to invest in environmental protection that goes beyond regulatory compliance." For KLM Royal Dutch Airlines, Blended Winglet equipped 737-900s will continue to provide important fuel savings while adding to fleet commonality -- the airline will be installing 21 additional Blended Winglet Systems on the 737-800 beginning in March 2007. All 737-800s in KLM's fleet will be Winglet equipped by February 2008. "Continental remains steadfast in its efforts to improve aircraft performance and reduce fuel usage. Equipping our 737-900s with Blended Winglets moves us closer to that goal," says John Greenlee, Managing Director of Fleet Planning for Continental. "The fuel efficiency improvements offered by Blended Winglets coupled with our young fleet provide Continental with a natural hedge against volatile fuel prices." For Continental Airlines, Blended Winglet equipped 737-900s will complement the carrier's existing winglet equipped aircraft, which include 100% of its 737-700s, 737-800s and 757-200s. To date the airline has installed winglets on 182 aircraft and plans to add over 100 additional Systems in the next few years as it will soon begin retrofitting winglets onto its 737 Classic fleet while continuing to take new 737NG aircraft with winglets, including the new 737-900ER. "Our long-haul flying will benefit greatly from the fuel savings and payload advantages provided by blended winglets," said Scott Ridge, Alaska Airlines' managing director of technical operations and support. "We've seen the value of the winglets on our other next-generation 737s and look forward to achieving similar efficiencies with our -900s." Alaska's order for 9 shipsets of 737-900 Blended Winglets adds to their current order of: 19 737-700's and 37 737-800's of which 33 are already in service. By year-end 2006, over 1500 Blended Winglet Shipsets will be in service with over 100 airlines in more than 40 countries on 6 continents. Currently, 65% of in-service fleet of 737-700s, and 57% of in-service 737-800s, are Blended Winglet Equipped. By 2010, with over 4500 airliners upgraded, APB anticipates that Blended Winglet Technology will have saved commercial airlines over 2 billion gallons of fuel. 5 Apr 2005 - MAS to install winglets for Boeing The Boeing Co. signed a deal with Malaysia's national carrier yesterday to set up a regional winglet modification center outside the capital, Kuala Lumpur, a Boeing official said. Aviation Partners Boeing and Malaysia Airlines Engineering sealed the agreement yesterday in Kuala Lumpur, agreeing to operate the first center in Southeast Asia to install fuel-saving winglet technology on Boeing's 737s. The pact will enable the engineering firm to become a one-stop shop for airlines, said Craig McCallum, sales director of Aviation Partners Boeing. More than 100 aircraft are expected to go through the Malaysian center for conversion in the next three to four years, McCallum said. The facility will cater to the needs of airliners from countries such as Indonesia, India and Malaysia. Boeing will provide all manufacturing and engineering support, tools and training to the center. The announcement comes amid rumors that Malaysian Airlines is considering buying 737-800s. However, Boeing denied any link between the airline's purchase order and the facility deal. The Malaysia facility will be the fourth in the Asia-Pacific region, joining facilities in China, Hong Kong and New Zealand. "Growth in blended winglet sales has been nothing short of spectacular lately, and much of this growth has been in the Asia-Pacific region," Mike Marino, Aviation Partners Boeing CEO, said in a statement. Introduced in 1999, the winglet technology has become popular because of the significant fuel savings it provides for aircraft -- ranging from 100,000 to 250,000 gallons per year per aircraft. The winglet system is currently available for Boeing 737s, and efforts are under way to offer them on 757s, 767s and 777s in the future. 14 Jan 2005 - Hapag-Lloyd Original Launch Customer Comes Back for More APB Blended Winglets Hapag-Lloyd Flug, a member of the TUI Group and the launch customer for Boeing 737-800 Blended Winglets 4 years ago, has ordered 10 additional Blended Winglet Systems. The Boeing Company will install the Blended Winglets as Buyer Furnished Equipment (BFE) on new 737-800s to be delivered between January 2006 and May 2007. Hapag-Lloyd operates a 100% Blended Winglet Equipped fleet of 737-800s. After 4 years of enjoying dramatic fuel savings, along with measurable performance and environmental benefits made possible with Blended Winglet Technology, this leading charter operator is sold on the benefits of Aviation Partners Boeing Technology. "This important order is a real affirmation of the outstanding value of our product," says Aviation Partners Boeing CEO Mike Marino. "Hapag-Lloyd, our most experienced customer, has an intimate understanding of the compelling value of Blended Winglet Technology." Hapag-Lloyd enjoys a wide range of operational benefits with Aviation Partners Boeing's patented* Blended Winglet Technology. At current fuel prices the fuel savings alone translates into a Blended Winglet Payback of under 4 years. Additional important benefits include greater payload-range capability and environmental advantages in terms of reduced engine emissions and reduced noise on takeoff. Aviation Partners Boeing Vice President of Sales & Contracts Patrick LaMoria reports that Hapag-Lloyd needed no convincing to come in with its second Blended Winglet order. "Hapag-Lloyd's experience operating with Blended Winglet Technology has made including them with every new Boeing aircraft they operate a very simple decision." By mid-2005 over half of all Boeing 737-800 and 700 series aircraft will be equipped with Aviation Partners Boeing Blended Winglets.  7 Oct 2004 - Continental Airlines to Take Shipset #500 for NG Boeing 737-800 While delivery of shipset 500 is a milestone in the history of Aviation Partners Boeing, it's just a hint of things to come as the global airline industry transitions to patented* Blended Winglet Technology. Blended Winglet Equipped Boeing aircraft are now flying on every continent. Current orders and options stand at over 1200 shipsets with a potential universe of 10,500 Boeing aircraft in the retrofit market alone. "We're only in the early stages in terms of meeting the growing demand for Performance Enhancing Blended Winglet Technology. But, it's a significant beginning," says Aviation Partners Boeing CEO Mike Marino. "Blended Winglet Equipped commercial aircraft save fuel, operate with enhanced performance due to a higher lift wing, and are measurably more environmentally friendly. Today's 500 Blended Winglet Equipped 737 are saving over 50 million gallons of fuel each year. If all Boeing aircraft worldwide were retrofitted with Blended Winglet Systems worldwide fuel savings would be close to 1.8 billion gallons each year." Aviation Partners Inc. developed Blended Winglet Technology in the early 1990s. Sized for maximum performance, and with a wider sweep transition between wing and winglet, Blended Winglets are typically 80% more effective than today's conventional angular winglet systems. Typical operator benefits include fuel savings of up to 5%, depending upon flight profile, improved performance from high and hot airfields, faster time to climb, lowered engine emissions and a 6.5% reduction in takeoff noise footprint. "The future is as exciting for us as it is for our customers worldwide who look forward to improving the performance, fuel savings and overall return on investment of their aircraft," says Aviation Partners Boeing Chairman Joe Clark. "We believe that anytime you can improve the productivity and environmental benefits of an existing airplane, it's a wise investment." 10 Jul 2003 - Air Plus Comet Becomes World's First Operator of Boeing 737-300 with Winglets Air Plus Comet yesterday became the world's first operator of a Boeing 737-300 with advanced-technology blended winglets and the latest carrier in Spain operating Boeing airplanes. The winglets, which curve out and up from the plane's wing tips, improve an airplane's performance and allow it to fly more than 185km farther than a 737-300 without winglets. Winglets also offer excellent environmental benefits, including reduced fuel use, takeoff and landing noise, and in-flight engine emissions. "As the first worldwide customer for the new 737-300 blended winglet, we will be the first to experience the fuel savings and environmental benefits they bring," said Alejandro Avila, Air Plus Comet technical director. The 737-300, leased from Aircraft Leasing Management, was delivered today. Headquartered in Madrid, Air Plus Comet provides long-distance charter flights between Spain and European locations and the Americas. It began operations in 1997. Aviation Partners Boeing, a joint venture of Boeing and Aviation Partners, Inc., developed the winglets. The winglets can be installed on 737-300, -400, -700 and -800 models. More than 28 carriers fly nearly 300 winglet-equipped 737s.

18 Feb 2003 - 737-300 Winglet Certification Delay The STC for a retrofited winglet on the 737-300 has been delayed due to problems discovered during the low speed handling phase of flight testing in Arizona. The winglets were producing handling deficiencies near V2 at high gross weights caused by flow separation around the transition to the winglet. Possible solutions include aerodynamic to the wingtips and outboard vortex generators.

5 Dec 2002 - Blended winglet Boeing 737 makes European inroads Sobelair, a Belgian charter operation, is leasing its first Boeing 737-800 with blended winglets. The winglet gives the Wichita-made 737 reducing wing drag, and making the wing more aerodynamically efficient, officials say. "Sobelair flies particularly long routes to destinations in Africa, the Mediterranean and the Middle East," says Aviation Partners Boeing sales director Patrick LaMoria, who is handling the lease. By the end of 2002, close to 200 Boeing Next-Generation 737s will be equipped with APB's patented Blended Winglet Technology. Following introduction of Blended Winglet Systems for Classic Series 737s, mid-2003, APB will certify Blended Winglet Systems for the 747-400.

Oct 2002 - Boeing 737-300 Blended Winglets Delivered Kawasaki delivered its first Blended Winglets. to Aviation Partners Boeing (APB) in October. Kawasaki is designing, developing and manufacturing the patented innovative winglets for the Boeing 737-300/400/500 models under an official agreement inked with APB in October last year (see Feb. 2002 Business Activities). Blended winglets, which are made of a high-tech composite material specially developed for aircraft, are attached to the tips of the wings to enhance performance by extending flight ranges, reducing noise and making other improvements. Winglets are already a standard feature on the Boeing Business Jet. The Boeing 737-700/800 models and Gulfstream's GII Business Jets have also been equipped with them. It is anticipated that they will also be fitted to a wider range of Boeing's existing aircraft, including the 747, 757 and 767 fleets. There are currently 1,000 Boeing 737-300 jetliners in operation around the globe. The winglets will be available as an option for those Boeing aircraft being retrofitted. Kawasaki used its proprietary KMS- 6115 composite material to create the latest winglets. KMS-6115 is made from high-performance carbon fibers and toughened epoxy resin, with much greater tensile and compressive strength than conventional composite materials. This is the first time KMS-6115 will be used in a Boeing aircraft.

26 Feb 2002 - Partnership with Boeing 'starting to take off' Seattle PI -- If you choose to sleep with an elephant, just be careful it doesn't roll over during the night. The advice, and warning, came from a well regarded aerospace executive of a small company who years ago lay down with an industry giant for a promising joint venture. It proved a painful experience. The executive mentioned the elephant adage recently when talking about Joe Clark, founder of Aviation Partners, a small Seattle company that developed revolutionary blended winglets that attach to the end of an airplane wing to improve performance. Clark has been sleeping with an elephant since the 1999 Paris Air Show. It was there that Clark and The Boeing Co., the biggest aerospace company and commercial airplane maker on the planet, announced the formation of Aviation Partners Boeing, a joint venture to put Clark's blended winglets on 737 jetliners. While acknowledging there have been "growing pains," "cultural clashes" and "learning experiences," Clark also said the partnership with Boeing is "really starting to take off." A growing number of next generation 737 operators around the world have opted for the blended winglets, which can boost fuel efficiency by as much as 4 percent. And they have helped Boeing win orders over Airbus. One of Boeing's most important order victories last year was the decision by Qantas, Australia's flagship carrier, to buy 15 737-800s and take options for at least 40 more. People close to the deal said the blended winglets offered on the Boeing plane gave it a small but important performance edge over the Airbus A320 on new long-haul domestic routes planned by Qantas. The blended winglets are offered as a retrofit for the 737-700 and the bigger 737-800. They are offered by Boeing as a factory-installed option only on the 737-800. So far, more than 80 next generation 737s have been equipped with blended winglets, along with about 60 Boeing Business Jets, a modified version of the 737 commercial jetliner. The winglets are standard equipment on all Boeing Business Jets. Clark expects that another 180 next generation 737s will be equipped with the blended winglets this year. Of those, about 50 will probably be factory-installed in Renton, he said. About a dozen airlines are either flying winglet-equipped 737s or have them on order. "We are talking actively with another dozen airlines," Clark said during a recent interview at his Aviation Partners office near the King County Airport terminal at Boeing Field. "We will be announcing more orders soon." Clark is even talking with the military and defense contractors. He met recently met with officials at Northrop Grumman about putting blended winglets on the Global Hawk unmanned aerial vehicle that has been used in Afghanistan. The winglets would add about two hours of flight time for the Global Hawk, Clark said. "Every plane should be designed with winglets," Clark said. Winglets were common on business and commercial jets before Aviation Partners arrived on the scene. But those traditional winglets, found on all Airbus models and the Boeing 747-400, rise at a sharp angle from the wing. Blended winglets gently curve up, as if they are part of the wing. Winglets were first developed by NASA in the 1960s to help reduce drag. Increasing the wing span can produce the same results. But wings of jetliners can't get any longer and still fit at airport gates. What's more, increasing wing span means structural changes that add weight. So far, the only U.S. carrier with 737s equipped with blended winglets is American Trans Air. But Clark recently presented his friend John Kelly, chairman of Alaska Airlines, with a small model of a 737-700 with blended winglets. The two men have known each other since the days when Clark teamed with Milt Kuolt in 1981 to form Horizon Air, a regional carrier later sold to Alaska. The model Clark gave to Kelly was painted in the livery of Alaska Airlines, with the Eskimo logo on the winglets. "A picture is worth a thousand words," Clark said, explaining why he was giving the model to Kelly. Continental is another 737-700 operator being wooed. The 737 is the world's most frequently flown jetliner. More than 4,000 have been built. Later this year, the blended winglets are to be certified by the Federal Aviation Administration for the older "classic" 737s, starting with the 737-300. Certification will follow for the 737-400 and 737-500. His company's business plan includes blended winglets for the 757, 767 and 747, Clark said, as well as for the MD-80 series. "The retrofit market is huge," Clark said. "Our schedule is to certify the classic 737s this year, the 747 next year, the 767 after that and then the 757." The winglets designed for the next generation 737 are about 8 feet high. Bernie Gratzer, former chief aerodynamicist at Boeing who was part of Clark's team at Aviation Partners that developed the blended winglets, said the 747 flight tests showed the winglets reduced drag by about 6.3 percent. That can mean substantial fuel savings for an airline. Clark has been approached by operators of older 747s, asking about retrofitting their planes with the blended winglets. "We think we can save them about a million gallons of fuel a year per plane," he said. But Boeing is not sold on blended winglets, at least for its bigger jets. Boeing engineers developed a raked tip, which does not bend upward like a winglet, for the 767-400 and will use those raked tips for the longer-range 777-300 now in development. And Boeing is considering raked tips, not blended winglets, for future longer-range versions of its 747-400. "Why put raked tips on a 747? That's a good question," said Gratzer, who retired from Boeing in 1986 and later was a professor at the University of Washington's aeronautics and astronautical department. "We don't really understand why they (Boeing) would do that," he added. But it was not so long ago that many engineers at Boeing scoffed at the notion that winglets would do anything other than give the 737 a more sexy appearance. After all, wasn't that why all those rich guys who could afford private jets wanted ones with winglets? At the Paris Air Show in 1997, Boeing's Borge Boeskov approached Clark about blended winglets on the planned Boeing Business Jet, a next generation 737-700 with the strengthened wing of the 737-800. Clark's subsequent business proposal for Boeskov said the Boeing Business Jet would get from 4 to 5 percent better performance with blended winglets. "The corporate guys like the looks of these things because they differentiate the product, but frankly my engineers have told me they don't work," Borge told Clark. So Clark told Boeskov his small company would foot the bill to design winglets for the Boeing Business Jet if Boeskov would test fly them on the plane. Unable to get Boeing engineers to go along, Boeskov turned to the German carrier Hapag-Lloyd, a longtime Boeing 737 customer. Hapag-Lloyd supplied one of its new 737s, and the results were better than Clark had predicted -- a nearly 7 percent reduction in drag. Hapag-Lloyd is now one of those customers operating 737s with blended winglets. Clark, who is not at all shy about expressing his opinions, is careful in talking about the challenges he has faced working with the world's largest aerospace company on an idea that Boeing's best and brightest once rejected. "They are a big bureaucracy and we sometimes want to get things done quickly," Clark said of the joint venture with Boeing. He credited Alan Mulally, Boeing's commercial boss, with helping change attitudes within the company. "Since Alan has gotten behind this, it has changed overnight," Clark said. "We talked about five months ago and he said he would really get behind the winglets program. "Since then, sales have really taken off. Our relationship with everyone at Boeing has gotten much better." Then he added, "Of course, we still have our differences." So far, though, the elephant has not rolled over.

8 February 2002 - Kawasaki of Japan will build 737 winglets Friday, February 8, 2002 SEATTLE POST-INTELLIGENCER STAFF AND NEWS SERVICES TOKYO -- Kawasaki Heavy Industries Ltd., Japan's second-biggest aerospace company, said it will develop wingtips for Boeing Co. 737s, adding to an existing cooperation with the company. Kawasaki Heavy will make blended winglets, which increase fuel efficiency and range, the companies said. The companies didn't provide financial details. Owners of 737s, of which more than 1,900 are in service around the world, will be able to fit the wingtips onto their planes, the release said.

SEATTLE, Sept. 11, 2001 - The first Boeing 737-700 arrived in Kenya Monday, making Kenya Airways the first airline anywhere in the world to operate a 737-700 with blended winglets. Kenya Airways is expected to put the airplane into service later this month. The airplane will be leased through GE Capital Aviation Services. "Our goal is to become the premier airline of choice in Africa and provide more frequency for passengers," said Isaac Omolo Okero, chairman for Kenya Airways. "The 737's economics and low maintenance cost will help us continue to provide the best service to destinations throughout Africa." The retrofitted blended winglets on the 737-700 curve out and up from the wingtip, reducing aerodynamic drag and boosting performance. Some of the potential improvements include better fuel burn, increased range, improved takeoff performance and obstacle clearance. Working with Aviation Partners Inc., Boeing developed the blended winglet technology for the 737 airplane. "The addition of the winglets on the 737-700 will provide Kenya Airways with a superior product," said Kevin Bartelson, chief operating officer for Aviation Partners Boeing. "The new 737-700 with winglets will add value to operators and provide a technologically advanced product with a reputation for superior reliability." The family of 737s consisting of the 737-600, -700, -800 and -900 is the newest design and the most technologically advanced in the single-aisle market. "Kenya Airways' selection of the 737 airplane will help reduce its fleet costs, which directly affects the airline's bottom line," said Doug Groseclose, senior vice president of International Sales, Boeing Commercial Airplanes. "With the new 737s, Kenya Airways can continue to offer its customers a quality product and on-time in-service performance." The airplanes are designed to fly higher, faster, farther, quieter and with greater fuel efficiency than previous 737 models -- and the competition. Kenya Airways, one of the fastest growing and most profitable airlines in Africa, will use the new 737 to fly to key destinations in Africa and other domestic routes on the continent. There are more than 130 Boeing 737s operating in Africa and more than 4,000 737s in service today.

Boeing 737 Advanced-Technology Winglets Make World Debut   SEATTLE, May 21, 2001 -- Boeing Next-Generation 737-800 advanced-technology winglets made their world debut in revenue service last week with German carrier Hapag-Lloyd Flug. Hanover-based Hapag-Lloyd became the first airline in the world to fly 737-800s equipped with the cost-effective, environmentally friendly wingtip extensions on commercial routes. The carrier uses 737-800s with winglets on routes from Germany to Mediterranean destinations. The new winglets on the Boeing 737-800 curve out and up from the wingtip, reducing aerodynamic drag and boosting performance. They add about 5 feet (1.5 meters) to the airplane's total wingspan and allow the airplane to fly up to 130 nautical miles (240 kilometers) further. "The winglets on our 737-800s will cut the airplane's already low fuel consumption, emissions and takeoff noise and make them even more eco-friendly," said Wolfgang Kurth, Hapag-Lloyd managing director. "Less fuel means more range and gives us the opportunity to open new markets" The fuel consumption of the 737-800s without winglets in Hapag-Lloyd's fleet already is as low as 2.1 liters per 100 seat kilometers. "We expect the winglets to decrease fuel burn even further - by up to 5 percent in cruise - and reduce the noise affected area by 6.5 percent," Kurth said. Winglets also have the potential to increase the optimum cruise altitude of the airplane, reduce engine maintenance costs, improve takeoff performance, and increase the weight the airplane can carry by .55 of a ton to 3.3 tons (.5 of a ton to 3 metric tons). "Next-Generation 737 winglets have proven their value in service on privately owned Boeing Business Jets, and now Hapag-Lloyd will see firsthand the unmatched benefits winglets can bring to commercial operators," said Toby Bright, Boeing Commercial Airplanes senior vice president for Europe and Russia. "Hapag-Lloyd, which was the first airline to order the new-technology 737-800s back in 1994, will once again make history as a company that quickly recognizes the importance of technological improvements in aviation." Hapag-Lloyd has started to retrofit its fleet of 27 Boeing 737-800s with winglets. Winglets initially were developed for use on the Boeing Business Jet, an adapted Next-Generation 737-700 with 737-800 wings, by Aviation Partners, Inc. (API). During the design process, Boeing and API formed a joint venture that further developed the design. The joint venture is called Aviation Partners Boeing (APB). Building a quieter, more fuel-efficient airplane was a top priority for Boeing engineers who initially designed the 737-800 and other members of the Next-Generation 737 family. The model's new CFM56-7 engines produced by CFMI, a joint venture of General Electric Co. of the United States and Snecma of France, meet community noise restrictions well below current Stage 3 limits and below expected Stage 4 limits. Emissions also are reduced beyond required standards.

Winglets boost to Boeing 737--800 performance SEATTLE, Feb. 18, 2000 - The Boeing Company announced today that it is offering Next-Generation 737-800 customers a new, advanced-technology winglet as a standard option. The winglet will allow a new airplane that already flies farther, higher and more economically than competing products to extend its range, carry more payload, save on fuel and benefit the environment. The first Boeing 737-800 with winglets is expected to be delivered in the spring of 2001. All subsequent 737-800s will be equipped with structurally enhanced wings that will make it easier for owners of standard 737-800s to retrofit those jetliners with winglets. "The key to product leadership is to create a superior product, then continually improve it in ways that add value to customers," said John Hayhurst, vice president and general manager, 737 programs. "With this new winglet, the Next-Generation 737 will remain the most advanced airplane family in its class for the 21st century, just as it was for the 20th." A Next-Generation 737-800 equipped with the new winglet will be able to fly farther, burn 3 percent to 5 percent less fuel, or carry up to 6,000 pounds more payload. Other benefits include a reduction in noise near airports, lower engine-maintenance costs, and improved takeoff performance at high-altitude airports and in hot climate conditions. The winglets weigh about 120 pounds each. They are made of high-tech carbon graphite, an advanced aluminum alloy and titanium. The winglet is eight feet long and tapers from its four-foot wide base to a width of two feet at the tip. Unlike traditional winglets typically fitted at abrupt angles to the wing, this new advanced "blended" design gently curves out and up from the wing tip, reducing aerodynamic drag and boosting performance. The 737-800 winglet was developed initially for the Boeing Business Jet (BBJ), which also features the state-of-the-art 737-800 wing. This winglet will be available initially as an option on the 162-passenger 737-800. Formal availability of the winglet will follow quickly on other models that feature the 737-800 wing, including the 737-700C and the 737-900. The applicability of the winglet to Next-Generation 737-600 and 737-700 models is being assessed. The blended-winglet technology was developed by Aviation Partners Inc. of Seattle. In 1999, during the design of the BBJ winglet, Aviation Partners and The Boeing Company formed Aviation Partners Boeing (APB), a joint venture that completed and owns the design. APB is developing the capability to make the winglet available as a retrofit for airplanes already in service.

SEATTLE, Oct. 23, 2000 - German carrier Hapag-Lloyd Flug became the first airline to fly the Boeing 737-800 with blended winglets. The test flight took place Sept. 26 2000 in Seattle.

First BBJ flight with winglets Feb 22, 1999

Boeing Business Jets Announces Winglets Test SEATTLE, June 4, 1998 — Boeing Business Jets announced today that it has been testing the use of winglets on a Boeing 737-800 for possible application on the new Boeing Business Jet (BBJ). The winglets are being tested as a possible range-performance enhancement for the BBJ. Designed and manufactured by Seattle-based Aviation Partners Inc., the two 8-foot high, blended and vertically mounted winglets are attached to the end of each wing of the airplane. "The Boeing Business Jet's 6,200 nautical-mile range already ranks it with the leading business airplanes in its class," said Borge Boeskov, president of Boeing Business Jets. "We want to test the application of winglets as a way of making a world-class product even better. We are testing to determine whether winglets will provide a range-performance enhancement by reducing drag." The BBJ is a derivative of the Next-Generation 737-700, combining the -700 fuselage with the strengthened wings and landing gear of the larger and heavier 737-800. This combination gives the BBJ a range of 7,140 statute miles (6,200 nautical miles, 11,480 kilometers). "As a special-use airplane for executive teams and private owners, the BBJ will fly much longer routes - up to 14 hours nonstop - than commercially operated Boeing 737s," Boeskov said. "These are the routes where winglets would have the best opportunity for performance improvements." In addition to performance, winglets will give the Boeing Business Jet a look that will set it apart from other business and commercial jets of its size. "We want the BBJ to stand out, and we want it to look distinctive among all other business jets," Boeskov said. Boeskov said the first phase of flight-testing will be completed this week. Whether winglets will be used on the BBJ will be determined following evaluation of testing data. Major assembly of the first BBJ fuselage was recently completed in Wichita, Kan., while work on the first wings and other components is progressing in the Puget Sound area. The airplane's first flight is scheduled for August. Boeing Business Jets is a joint venture between The Boeing Company and General Electric Co.