The Boeing 777 is a popular twin-engine wide-body long-haul aircraft. Since its launch on United Airlines in June 1995, Boeing has delivered more than 1,600 copies in all its variants. It is also developing a next generation ‘triple-seven’ series, known as the 777X. However, in contrast to several other Boeing projects, the 777 family aircraft do not feature winglets. But why is this the case?
What purpose are winglets for?
In a cost-driven industry, such as commercial aviation, winglets are a useful tool for saving money for airlines. These vertical extensions of an aircraft’s wingtips reduce the amount of aerodynamic drag caused by the aircraft while cutting through the air. This drag is usually associated with the vortexes that the wingtips of an aircraft create during flight.
Winglets help to reduce the size of these vortexes and, subsequently, the amount of drag. This has a useful drag effect as it improves fuel efficiency and, consequently, range. In addition, consuming less fuel also saves money for airlines. This feature has several different designs, including inclined, combined winglets, sharklet and split scimitar.
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Why doesn’t the 777 have winglets?
One reason the 777 does not have such wing tip extensions is the operational limits that this would impose on the aircraft. The aircraft’s 777-200LR and -300ER variants have a wingspan of 64.8 meters. This only falls below the upper limit for the ICAO aerodrome E code.
The upper limit for this category is 65 meters, and adding winglets would exceed that. This would result in the aircraft being classified under aerodrome code F. This categorization is the same as that of larger aircraft, such as the Airbus A380 and Boeing 747, and would limit its versatility. Manufacturers also need to consider the additional weight that winglets give an aircraft.
In addition, later designs, such as the 777F shown below, feature slanted wing tips. This change in profile at the end of the wings offers efficiency benefits similar to winglets. As such, this left little need for Boeing to also extend the wingtips of the type upward. Similar tilted wing tip designs can also be found on their 747-8, 777X and 787 ‘Dreamliner’ aircraft.
Wing technology in the next 777X
Looking ahead, the next Boeing 777X series will feature a variety of technological improvements over its predecessors. One of these futuristic aspects will be to fold the tips of the wings. Boeing is expected to be the first manufacturer to deploy this technology on a commercial aircraft. However, interestingly, its European competitor Airbus also patented a similar system in 2014.
The Boeing 777X folding wingtips will offer additional versatility to its operators. This is because, normally, its 71-meter wingspan would be so large that it would fall under the aforementioned ICAO aerodrome F code. However, by folding the wingtips inward on the ground, this is reduced to 64.8 m.
Much like the previous 777 variants of the 777, this means that the 777X is narrow enough to be classified under the aerodrome code E. As such, operators will be able to fly the 777X to a wider range of airports than if it did not have this. resource . In addition, as it shares the same category as the older 777s, this will allow for greater flexibility in terms of switching variants.
What do you think of the Boeing 777 family as a whole? Have you ever flown in one or perhaps multiple triple-seven variants? Let us know your thoughts and experiences in the comments!