Summary Winglets help to reduce drag and increase efficiency and are a common sight on most modern jetliners.
Boeing 737 models have gone through 4 types of winglets: Mini, Blended, Split Scimitar, and Advanced Technology for the MAX.
Advancements in winglet design for the 737 MAX reduce fuel burn by 2% using Natural Laminar Flow Technology.
The Boeing 737 is one of the most successful commercial aircraft in aviation history. The type first took to the skies in April 1967, just two years after the program was launched. The aircraft has significantly evolved since then, going through multiple modifications and updates to make it more efficient, ultimately contributing to its success story.
The Boeing 737 has four distinct generations – the Original, Classic, Next Generation (NG), and MAX. Winglets were one of the most distinct features to start appearing on the 737 at the turn of the century. The devices have contributed to increasing the efficiency of the aircraft and are now present on the majority of 737s flying today. Let us explore how the 737’s winglets have evolved over the years.
Benefits of winglets on commercial aircraft
Almost all modern commercial jetliners have winglets. These are aerodynamic devices placed on the tips of aircraft wings to improve aircraft performance by reducing drag. Winglets help reduce the formation of the powerful vortices that curl out behind the wingtip as the aircraft cuts through the air.
Wingtip vortices are formed when the low-pressure air flowing over the wing and the high-pressure air under the wing meet at the tip. They increase drag, which slows down the aircraft. This needs to be countered with increasing thrust, which results in more fuel burn.
While winglets have been around for longer, Boeing first flew them on the 737-800 in June 1998 as a testbed for use on the BBJ. According to the Boeing 737 technical site, four different types of winglets are available for the 737, which we will explore in detail below.
Mini-Winglets : B737-200
: B737-200 Blended Winglets : B737 Classics and NGs
: B737 Classics and NGs Split Scimitar : B737NG
: B737NG Advanced Technology: B737 MAX
Related The History And Differences Between Airbus And Boeing Winglets Winglets are a common feature found on many modern commercial aircraft types.
The 737-200 mini-winglets
The Boeing 737-100 made its maiden flight on April 9, 1967. Lufthansa was the launch customer of the type and eventually the largest operator. With a need for a slightly higher passenger load, Boeing responded with the 737-200, which could carry up to 15 more passengers.
The 737-200 was succeeded by the -300, which was part of the Classic generation. Other models include the 737-400 and -500. Early Boeing 737s did not have distinct winglets. However, the 737-200Adv, shown above, was one of the classics fitted with mini-winglets. This was part of the Quiet Wing Corp flap modification kit, certified by the Federal Aviation Administration in 2005.
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737 Next-Generation blended winglets
Boeing initially started investigating blended winglets in the mid-1980s, and they were further developed in the early 1990s by Aviation Partners, a Seattle-based private corporation leading in Blended Winglet technology. These winglets are curved gently outwards at the end of the wings and blend seamlessly into the wings themselves.
Photo: Lukas Wunderlich | Shutterstock
They were first installed on Gulfstream II aircraft, and the resulting range and fuel efficiency improvements sparked some interest at Boeing. In 1999, Aviation Partners Boeing (APB) was formed, a joint venture between Aviation Partners and the American planemaker, to develop blended winglets for its aircraft.
The manufacturer adopted the technology as standard equipment for the BBJ in 2000, with APB certifying the winglets for the 737-700 and 737-800 in 2001. Over time, the company certified blended winglets for retrofit installation on other 737 models, including the following:
737-300: May 2003
May 2003 737-500: May 2007
May 2007 737-900: October 2007
Blended winglets were installed in production on Next-Generation 737-700s, -800s, and -900ER models. They are now the most common type of winglets that can be found on modern commercial aircraft. They can also be found on Boeing 757s and 767s.
737 NG Split Scimitar Winglets
Split Scimitar Winglets, an enhancement to Boeing’s standard Blended Winglets, were introduced in early 2014 and are available as a retrofit to existing winglet aircraft. They feature two distinct parts, with the lower part angled downwards to reduce drag further.
Photo: MC MEDIASTUDIO | Shutterstock
In July 2013, the first 737 to feature the Split Scimitar Winglet made its maiden test flight at Paine Field. It was a 737-800 that belonged to United Airlines. In 2014, it became the first carrier to deploy an aircraft retrofitted with Split Scimitar Winglets into revenue service. United Airlines Vice President of Fleet Ron Baur said at the time,
“We are always looking for opportunities to reduce fuel expenses by improving the efficiency of our fleet. The Next-Generation 737 Split Scimitar Winglet will provide a natural hedge against rising fuel prices while simultaneously reducing carbon emissions.”
Many airlines, including Ryanair, have retrofitted their aircraft with this technology. According to Aviation Partners, the combined aerodynamic elements of the retrofit, including the ventral strakes, scimitar tips, and trailing edge wedges, provide a drag reduction and corresponding range increase of at least 2% for longer-range flights. Split Scimitar Winglets have become standard on all new Boeing Business Jets and are in service on over 700 B737NGs.
737 MAX Advanced Technology Winglets
Boeing’s latest generation 737 is the MAX, which comes in four variants – the MAX 7, 8, 9, and 10. While also known for some of its unfortunate issues and incidents over the last few years, the aircraft is one of the most-used modern narrowbodies in the world and remains an efficient and reliable type.
Photo: Skycolors | Shutterstock
It features the Advanced Technology (AT) Winglet, a combination of rake tip technology and a dual feather winglet concept, which forms one advanced treatment for the MAX’s wings. It uses what Boeing calls “Natural laminar Flow Technology.” The planemaker also dubs the AT winglet “the most efficient ever designed for a production plane.” They are said to reduce fuel burn by approximately 2%.
The AT winglets look similar to the Split Scimitar Winglets on the 737NG model. The winglets on the MAX measure about 8 ft (2.4 m) from the root to the top and 9 ft 7 in (2.9 m) in from the lowest to the highest tip. The top part measures 8 ft 3 in (2.5 m), while the bottom measures 4 ft 5 in (1.35 m).
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