Cánh nhỏ đầu cánh (Winglet)

Là Gì a Winglet?

A winglet is an upturned or specially shaped extension fitted at the tip of an aircraft's wing. Winglets are aerodynamic devices designed to reduce the induced drag created by wingtip vortices — the spiraling columns of air that spill from the high-pressure underside of a wing to the low-pressure upper surface at the tip. By redirecting and diffusing these vortices, winglets allow aircraft to fly more efficiently without increasing the physical wingspan.

Chức Năng và Mục Đích

Induced drag accounts for a significant portion of total drag during cruise — typically 30–40% on commercial jets. At any given lift level, induced drag decreases as wingspan increases. Winglets effectively increase the aerodynamic span without proportionally increasing the structural span, avoiding gate compatibility problems at airports designed for standard wingspan envelopes.

The fuel savings from winglets are tangible: Boeing estimates that blended winglets on the 737 Classic and Next Generation reduce fuel burn by 3–5% per flight. On a high-utilization aircraft flying 3,000 hours per year, that translates to hundreds of thousands of dollars in annual fuel savings per aircraft.

Các Loại và Biến Thể

• Blended winglet: A smoothly curved transition from wing to winglet, minimizing interference drag at the junction. Standard on Boeing 737NG.
• Sharklet (split-tip): Airbus's term for the large, gently curved winglets on the A320neo family, offering up to 4% fuel savings versus the ceo variant with no winglets.
• Raked wingtip: Used on the Boeing 787 and 777X — not a traditional vertical winglet, but a swept-back tip extension that achieves similar drag reduction through span increase.
• Split Scimitar winglet: Adds a lower strake below the existing blended winglet (retrofittable to 737NG), providing an additional 1.5–2% fuel benefit.
• Aviation Partners Boeing (APB) winglet: Retrofittable blended winglets offered for older 737 Classics and 757s by Aviation Partners.

Ví Dụ Tiêu Biểu

The Airbus A350 XWB employs large curved winglets as an integral part of its composite wing design, contributing to its class-leading fuel efficiency. The Boeing 737 MAX features distinctive "Advanced Technology" winglets — a dual-tip design with both an upturned and a small downturned element — optimized for the aircraft's new LEAP-1B engines. The Embraer E2 family integrates winglets designed alongside a new high-aspect-ratio wing, yielding up to 25% better fuel burn than its predecessor.

Các Thành Phần Liên Quan

Winglets work in concert with flaps to manage the wing's aerodynamic behavior across the flight envelope. While flaps increase lift at low speeds, winglets primarily benefit cruise efficiency by reducing drag. Together, optimizing both components is fundamental to modern fuel efficiency improvements in commercial aviation.