We all know that winglets, or those little “fins” you see at the wingtips of an aircraft, serve a purpose, and that is to improve efficiency and save fuel. You now see these commonly among new-generation passenger aircraft such as the Airbus A350, A320, newer generation Boeing 737 variants, and even the Boeing 747-400. However, if you notice the newer Boeing planes such as the 777 and even the 747-8I and the 787, they have no winglets. Well, actually, they do have wingtip devices that improve efficiency but they come in a different form.
This once made me wonder why Boeing ditched those winglets in exchange for raked wingtips while Airbus still uses winglets on its newest plane, the A350.
This design choice, made by Boeing, is rooted in a thorough cost-benefit analysis and a deep understanding of aerodynamics. The decision to forego winglets on the 777 is based on a balance between fuel efficiency, operational practicality, and aerodynamic optimization.
The Role of Winglets and Raked Wingtips
Winglets, commonly seen on aircraft like the Airbus A320 and Boeing 737, are designed to reduce drag and improve fuel efficiency. However, they come with their own set of challenges, including added weight, potential for flutter, and the complexity of retrofitting them onto existing aircraft designs. In contrast, the Boeing 777 employs raked wingtips, an alternative aerodynamic feature that effectively reduces drag without the drawbacks associated with conventional winglets.
Raked wingtips, as seen on the 777-300ER, -200LR, and -200F models, extend the wingspan and enhance aerodynamic efficiency. These wingtips are designed to reduce takeoff field length, improve climb performance, and decrease fuel burn, much like conventional winglets. However, they do so without significantly increasing the aircraft’s wingspan, allowing the 777 to maintain compatibility with airport gates and infrastructure.
The Tradeoffs and Design Choices
Boeing’s decision to choose raked wingtips over conventional winglets for the 777 was influenced by various factors. The design of the 777, with its notably long wings, posed a challenge in terms of fitting into typical airport gates. Boeing initially considered folding wingtips to address this issue, though this feature was not immediately popular.
In designing the 777, Boeing explored all options, including the use of winglets. However, the aerodynamics engineering team, led by Dave Akiyama, understood the complexities and risks associated with winglets, such as the issue of flutter. They concluded that span extensions, like raked wingtips, were the simplest and least risky approach to achieve the desired aerodynamic benefits.
Furthermore, Boeing has pursued various methods to enhance the 777’s fuel efficiency beyond just wingtip modifications. The Performance Improvement Package (PIP) for the 777 is a prime example, improving fuel burn by 1% through a combination of different strategies. This approach highlights Boeing’s commitment to optimizing aircraft performance through diverse design and technological innovations.
This explains why the Boeing 777 has no conventional winglets, but instead uses raked wingtips. It is a result of careful aerodynamic consideration, operational practicality, and the goal of achieving optimal fuel efficiency. The decision to use raked wingtips on the 777 is based on aircraft design, balancing aerodynamic efficiency with practical operational considerations.
First love never dies. I fell in love with airplanes and aviation when I was a kid. My dream was to become a pilot, but destiny led me to another path: to be an aviation digital media content creator and a small business owner. My passion for aviation inspires me to bring you quality content through my website and social accounts. Aviation is indeed in my blood and blog!
Windtips are a trend, just that. You can give millons of arguments to adopt them and I could give you the same to avoid them. The most efficient are the self adapting ones…..million years of evolution could prove that