Fact-checked by Grok 2 weeks ago

Wing tip

A wing tip is the outermost edge of an aircraft's wing, located farthest from the fuselage and marking the end of the wing's span. This region plays a critical role in aerodynamics, as it is where wingtip vortices form due to the pressure difference between the upper and lower surfaces of the wing, leading to induced drag that reduces fuel efficiency and lift effectiveness.^[1]^[2]^[3] Wingtip vortices are counter-rotating spirals of air that trail from each wing tip, strongest during takeoff and landing when the aircraft is heavy, clean (no flaps or slats deployed), and slow. These vortices create downwash that tilts the effective airflow over the wing, increasing drag and posing a wake turbulence hazard to trailing aircraft. To mitigate these effects and improve performance, engineers have designed various wingtip devices, such as winglets, which are upward- or downward-curving extensions that weaken vortex strength by redirecting airflow, effectively increasing the wing's aspect ratio and thereby reducing induced drag.^[4]^[2]^[5] The concept of wingtip modifications dates back to 1897, when British engineer Frederick W. Lanchester patented end plates to counteract tip vortices, predating powered flight by the Wright brothers. Modern winglets emerged from NASA research in the 1970s, with early applications on business jets like the Gates Learjet in 1977, leading to widespread adoption on commercial aircraft such as the Boeing 747-400 and Airbus A320 families, resulting in fuel savings of up to 5-6% on long flights. Other devices include spiroids, split scimitars, and raked wingtips, each tailored to specific aircraft designs to balance drag reduction, structural weight, and manufacturing costs.^[6]^[7]^[6]

Overview

Definition and Anatomy

The wing tip, also known as the wingtip, is the outermost end of a fixed-wing aircraft wing, positioned farthest from the fuselage and marking the lateral extremity of the wing span.^[8] This region serves as the terminal boundary where the wing's aerodynamic surface concludes, influencing the overall structural integrity and load paths from root to tip.^[1] Anatomically, the wing tip typically comprises a wingtip rib, which forms the outermost structural frame maintaining the airfoil shape; a skin covering that provides the external aerodynamic surface; and potential attached structures such as fairings for smoothing airflow transitions.^[9] The rib connects to the main wing spars, which run spanwise and carry primary bending and shear loads, while the skin is fastened to underlying stringers and ribs to resist buckling and transmit forces.^[10] In relation to the broader wing structure, the wing tip integrates with the main spar system and often adjoins the aileron at the trailing edge, facilitating load distribution that decreases from the wing root toward the tip, thereby minimizing torsional stresses.^[9] This connection ensures continuity in the torsion-box design, where the tip contributes to overall wing stiffness without bearing the maximum root loads.^[10] Wing tip shapes vary to optimize structural and basic aerodynamic performance, including squared-off designs with a flat termination, rounded contours for smooth edges, and upturned or canted configurations that angle upward from the wing plane.^[11] Materials have evolved from traditional aluminum alloys, valued for their strength-to-weight ratio in spars and ribs, to modern composites like carbon fiber-reinforced polymers for the skin, offering reduced weight and corrosion resistance in contemporary designs.^[12] These variations in shape and material selection directly impact the tip's role in load distribution, with composites enabling lighter structures that enhance fuel efficiency.^[12]

Primary Functions

The wing tip plays a crucial role in roll control by integrating with ailerons, which are typically located on the outboard trailing edges near the tips of each wing. These control surfaces deflect in opposite directions—one upward to decrease lift on that wing and the other downward to increase lift—creating a rolling moment about the aircraft's longitudinal axis for banking during turns. This differential lift generation at the wing tips enhances the effectiveness of roll maneuvers, allowing precise control of the aircraft's attitude in flight.^[13] Structurally, the wing tip serves as a counterbalance to mitigate wing flexing and torsion, particularly in high-speed or gusty conditions where aeroelastic phenomena like flutter could compromise integrity. Concentrated masses at the wing tips, such as ballast or equipment, shift the center of gravity outward, increasing the natural frequency of wing oscillations and damping torsional modes to prevent destructive vibrations. This mass balancing is essential for maintaining structural limits under dynamic loads, as demonstrated in analyses of straight-winged aircraft where tip masses improved oscillatory stability margins.^[14]^[15] Wing tips also provide key mounting points for ancillary equipment, including navigation lights and anti-collision strobes, which are required for visibility and regulatory compliance. The left wing tip typically mounts a red position light, the right a green one, and both may incorporate white strobes to alert other aircraft, ensuring safe operations in low-visibility environments without significantly altering the wing's aerodynamic profile.

Aerodynamics

Wingtip Vortices

Wingtip vortices are rotating helical airflows that trail from the tips of an aircraft's wings during lift generation. They form as high-pressure air from beneath the wing spills over the tips into the low-pressure region above, creating spiraling motion that combines with the free-stream airflow to produce counter-rotating vortices.^[16]^[4] This spanwise flow is strongest at the wingtips, where pressure equalization occurs most intensely, resulting in cylindrical vortex cores that descend and eventually dissipate due to atmospheric viscosity.^[17] The primary aerodynamic effects of wingtip vortices include the generation of induced drag, downwash, and wake turbulence, all of which reduce aircraft efficiency. Downwash from the vortices deflects airflow downward behind the wing, decreasing the effective angle of attack and tilting the total aerodynamic force vector rearward to produce a drag component.^[17]^[4] Vortex strength, which governs the intensity of these effects, is directly proportional to the lift generated (influenced by aircraft weight) and inversely proportional to wing span, with heavier, slower aircraft producing the most persistent vortices.^[18] Wake turbulence arises as these vortices create hazardous rolling moments for trailing aircraft, particularly during takeoff and landing when vortices are strongest.^[19] Visualization and measurement of wingtip vortices typically involve smoke trails introduced into wind tunnels or flight test environments to reveal the helical paths and core structures.^[20] In wind tunnel studies, smoke injected near the model highlights vortex formation and evolution, allowing researchers to observe flow separation and rotation at speeds up to approximately 300 mph.^[20] Early aviation experiments similarly used smoke or tufts to document these phenomena, confirming their presence as trailing spirals from wingtips.^[16] Safety implications of wingtip vortices center on wake turbulence hazards, which can induce sudden rolls or loss of control in following aircraft, especially at low altitudes.^[18] To mitigate risks, the Federal Aviation Administration (FAA) and International Civil Aviation Organization (ICAO) establish minimum separation standards based on aircraft weight categories—such as 4 to 8 nautical miles or 2 to 4 minutes between departures—ensuring safer spacing during critical flight phases.^[19]^[21]

Drag Reduction Principles

The induced drag experienced by a finite wing arises primarily from the generation of wingtip vortices, which create a downwash that reduces the effective angle of attack across the span. This drag component can be quantified using the formula D_i = \frac{L^2}{\pi b^2 q e} where L represents the total lift, b the wingspan, q the dynamic pressure, and e the Oswald efficiency factor, a dimensionless parameter typically ranging from 0.7 to 1.0 that accounts for deviations from ideal elliptical lift distribution due to factors such as wing planform and tip geometry.^[22] Wing tip configurations directly influence e by altering vortex strength and spanwise flow, with optimized tips increasing e toward unity to minimize induced drag for a given lift.^[23]^[24] Span efficiency, closely tied to the Oswald factor, improves with designs that promote a more uniform downwash and reduce tip losses, often achieved through higher aspect ratios defined as AR = b^2 / S where S is the wing area. Increasing AR lowers induced drag proportionally to $1 / AR, as it spreads lift over a longer span and weakens tip vortices, though practical structural limits—such as increased bending moments and weight—constrain maximum values to around 10–15 for transport aircraft.^[22]^[23] Wing tip designs also play a critical role in managing the boundary layer to prevent tip stall, where spanwise outflow from high-pressure regions beneath the wing to low-pressure regions above accelerates flow separation at the tips. By incorporating features like sweep or fences, tip geometries can redirect this spanwise flow, energizing the boundary layer and delaying separation to higher angles of attack, thereby maintaining lift while reducing drag penalties from early stall.^[25] This approach modifies the spanwise lift distribution to suppress tip loading, ensuring progressive stall initiation at the root rather than the tip for better control characteristics.^[26] Computational fluid dynamics (CFD) models have become essential for simulating complex tip flows, enabling precise prediction of drag reduction without extensive physical testing. NASA studies utilizing panel methods and Reynolds-averaged Navier-Stokes solvers on configurations like the Common Research Model demonstrate that optimized tip shapes can reduce induced drag by 1–5% through refined wake modeling, capturing nonlinear effects such as vortex roll-up and boundary layer interactions.^[23]

Wingtip Devices

Winglets

Winglets are vertical or near-vertical extensions attached to the tips of an aircraft's wings, designed to mitigate induced drag by diffusing wingtip vortices.^[27] The concept was invented in 1974 by NASA engineer Richard T. Whitcomb during the 1973-74 oil crisis, drawing inspiration from observations of how soaring birds curl their primary wingtip feathers upward to reduce drag and enhance efficiency.^[28] Whitcomb's design aimed to redirect high-energy airflow outward and upward, weakening the rotational flow of wingtip vortices that forms due to pressure differences across the wing.^[29] The first flight test of winglets occurred on August 24, 1977, aboard a NASA-modified Gates Learjet Model 28, marking the debut of this technology on a civil aircraft and confirming its aerodynamic viability through wind-tunnel and in-flight validations. Common winglet designs include cantilevered types, which feature a sharp, upturned extension resembling a small vertical fin; blended winglets, which incorporate a smooth, curved transition from the wing to the tip device for reduced interference drag; and spiroid winglets, which form a continuous looped structure to further dissipate vortex energy without a distinct leading edge.^[30] These variations allow adaptation to different aircraft sizes and missions while maintaining the core principle of vortex control.^[30] In performance terms, winglets typically yield 3-5% improvements in fuel efficiency for commercial jets by lowering induced drag, enabling longer ranges or payload increases without additional power. This drag reduction also translates to lower emissions, with representative examples including the Boeing 747-400, which introduced winglets in 1989 and achieved notable fuel savings on long-haul routes. Similarly, the Airbus A320neo's sharklets, certified in 2012, provide up to 4% reductions in fuel burn and CO2 emissions, enhancing environmental performance for narrow-body operations.^[32]

Alternative Designs

Alternative designs to traditional winglets encompass a variety of wingtip modifications aimed at enhancing aircraft performance through drag mitigation, range extension, or improved handling characteristics. These include tip tanks, Hoerner-style tips, drooped or raked tips, and wingtip fences, each tailored to specific operational needs without relying on upturned extensions.^[33] Tip tanks are external fuel pods mounted at the wingtips, primarily used to extend aircraft range by increasing fuel capacity. On the Lockheed L-1049 Super Constellation, introduced in the late 1940s, optional 600-gallon tip tanks increased total fuel capacity by approximately 18% to 7,750 US gallons for the L-1049G model, enabling transoceanic flights for civilian and military variants like the L-1049G.^[34]^[35]^[36] While these tanks add significant weight—approximately 7,200 pounds (3,600 pounds per tank) when full with aviation fuel at 6 lb/gal—they also contribute to lateral balance by distributing mass outward along the wing, countering any forward center-of-gravity shifts from payload.^[37] This design was particularly valuable in the post-World War II era for long-haul propeller aircraft, though it increased structural loads and maintenance complexity.^[38] Hoerner-style tips feature rounded, low-drag fairings with a thin leading edge, sharp trailing edge, straight upper surface, and convex lower contour, developed to minimize turbulence and interference drag at the wingtip. Named after aerodynamicist Sighard F. Hoerner, these fairings smooth airflow and reduce vortex-induced losses, with studies indicating modest drag reductions and improvements in cruise performance for light aircraft.^[23]^[39] The Grumman American AA-1 Yankee, a light two-seat trainer from the 1970s, incorporated Hoerner-style tips as standard, which helped lower interference drag by streamlining the junction between wing and tip, improving overall efficiency for short-field operations without altering wing span.^[33] Drooped or raked wingtips involve downward curvature or increased sweep at the tip to optimize low-speed aerodynamics and lift distribution. Raked wingtips, in particular, sweep the trailing edge rearward more sharply than the main wing, enhancing lift near the tip while maintaining overall span limits for airport compatibility. The Boeing 787 Dreamliner, entering service in 2011, employs raked wingtips that improve low-speed handling during takeoff and landing by boosting tip lift and reducing stall tendencies, without the added structural weight of span extensions.^[40] This configuration achieves up to 5.5% drag reduction in cruise, surpassing conventional winglets, and supports the aircraft's composite wing flexibility for better gust response.^[41] Wingtip fences consist of short vertical plates extending upward and downward from the wingtip, serving as barriers to control spanwise flow and weaken wingtip vortices. Introduced on Airbus narrow-body jets in the 1990s and scaled up for larger aircraft, these fences deconcentrate vortex cores and shift vorticity aft, mitigating induced drag with minimal added weight or complexity. The Airbus A380, certified in 2007, utilizes dual-sided wingtip fences that provide cost-effective vortex management, avoiding the structural penalties of larger devices while enabling the high-aspect-ratio wing to operate efficiently on runways with tight gate constraints.^[42] This approach yields about 1-2% fuel savings on long-haul flights, prioritizing simplicity in the superjumbo's design.^[43] Split scimitar winglets feature an upper forward extension combined with a lower rearward one, enhancing vortex diffusion. Retrofitted on Boeing 737-800 and -900 models since 2014, they provide fuel savings of 1.5-2.2% compared to blended winglets.^[44]

Folding Wingtips

Mechanisms and Engineering

Folding wingtip mechanisms utilize hinge systems to balance structural loads and aerodynamic efficiency during both folded and extended configurations.^[45] These hinges are actuated by rotary actuators, hydraulic rams, or electromechanical drives, depending on the aircraft design. For example, the Boeing 777X employs an electromechanical actuation system supplied by Liebherr Aerospace, incorporating motors and a rotating actuator to pivot the wingtips reliably on the ground.^[46]^[47] The wingtips fold upward at approximately 90 degrees to minimize ground span while preserving flight aerodynamics. In the Boeing 777X, each wingtip folds upward by 3.5 meters, reducing the overall wingspan from 71.8 meters to 64.8 meters, with the complete cycle taking 20 seconds.^[48] This mechanism was demonstrated in static tests at Boeing's Everett Factory in October 2016, confirming the targeted folding time and operational reliability.^[49] To ensure structural integrity, folding wingtips incorporate reinforcements such as additional spars and robust locking systems capable of withstanding limit loads up to 2.5g during maneuvers.^[50] The Boeing 777X features electrical locks that automatically engage upon extension, securing the wingtips for flight and preventing inadvertent folding, with the hinge structure designed to limit motion through positive stops.^[47]^[51] When extended, folding wingtips incur minimal aerodynamic performance loss compared to fixed designs, as the system maintains the benefits of increased span for lift and drag reduction. Seals at the hinge joint prevent airflow gaps, ensuring a smooth surface and avoiding interference drag.^[52] For the Boeing 777X, this is anticipated to result in substantial in-flight efficiency gains, equivalent to those of non-folding high-aspect-ratio wings, without compromising extended configuration performance.^[48] As of November 2025, the 777X remains in certification testing, with entry into service expected in 2027.^[53]

Operational Applications

Folding wingtips play a critical role in carrier-based aircraft operations, enabling compact storage on aircraft carrier decks and elevators to maximize the number of aircraft that can be accommodated. The McDonnell Douglas F/A-18 Hornet, introduced in the early 1980s, exemplifies this application with its outer wing sections folding upward at 90 degrees for stowage, reducing the effective wingspan from 40.4 feet to approximately 27 feet when folded.^[54]^[55] This design facilitates efficient use of limited space on naval vessels and in onboard hangars, supporting rapid deployment and maintenance cycles during missions.^[54] In commercial aviation, folding wingtips address airport infrastructure constraints, allowing wide-body aircraft to access standard gates without requiring costly expansions. The Boeing 777X is designed with folding wingtips that reduce its wingspan from 71.8 meters (ICAO Code F) to 64.8 meters (Code E) when folded, ensuring compatibility with existing taxiways and gates designed for predecessors like the 777-300ER.^[56] The U.S. Federal Aviation Administration established certification standards for these wingtips in 2018, mandating secure locking mechanisms and ground crew procedures to maintain safety during ground operations.^[57] This feature supports global route flexibility for airlines, avoiding the need for specialized facilities at many international airports.^[58] Beyond flight operations, folding wingtips enhance maintenance and ground transport efficiency by minimizing the space required in hangars and during overland shipment. For instance, in carrier-based fighters like the F/A-18 Hornet, the folded configuration allows more aircraft to fit within base hangars, streamlining inspections and repairs in constrained environments.^[54] In tactical airlift scenarios, similar designs reduce logistical footprints for storage and relocation, as seen in military applications where wingspan limitations affect forward basing.^[59] The implementation of folding wingtips introduces a modest weight penalty due to hinges, actuators, and reinforced structures, but this is offset by substantial operational savings in fuel efficiency from extended spans during flight and reduced infrastructure costs.^[59] For the Boeing 777X, the design enables a 10-12% improvement in aerodynamic efficiency over prior models, translating to lower per-seat operating costs despite the added complexity.^[58] These benefits underscore the trade-offs in modern aircraft design, prioritizing versatility in diverse operational theaters.

Historical Development

Early Innovations

Preceding powered flight, British engineer Frederick W. Lanchester patented end plates in 1897 to counteract tip vortices.^[6] The pioneering Wright Flyer of 1903 marked the initial application of wing tip designs in powered flight, featuring simple wing tips integrated with a wing-warping control system instead of ailerons. This mechanism allowed the pilot to twist the outer portions of the wings in opposite directions using cables connected to a cradle operated by the pilot's hips, enabling roll control and basic lateral stability during the aircraft's historic first flights at Kitty Hawk, North Carolina. The design prioritized fundamental aerodynamic control over drag optimization, reflecting the era's focus on achieving sustained powered flight.^[60]^[61] During World War I, biplane fighters like the Sopwith Camel, introduced in 1917, adopted rounded wing tips for structural simplicity in their wire-braced wooden frameworks, which facilitated rapid production and ease of maintenance under wartime conditions. These tips contributed to enhanced longitudinal stability by increasing effective wing area near the tips, but they also exacerbated induced drag through less efficient spanwise lift distribution, making the aircraft notoriously difficult to handle at low speeds due to high stall tendencies and torque effects from the rotary engine. The Camel's design exemplified the trade-offs in early military aviation, where robustness often outweighed aerodynamic refinement.^[62]^[63] The transition to monoplanes in the 1930s brought tapered wing tips into prominence for improved efficiency, as seen in the Douglas DC-3 airliner of 1935, which featured a taper ratio of approximately 0.5 that distributed lift more elliptically along the span compared to rectangular predecessors. This configuration reduced induced drag by approximately 5-10% relative to untapered designs, enhancing cruise performance and range for commercial operations while maintaining structural integrity with an all-metal semi-monocoque construction. The DC-3's wing tips thus represented a key step toward optimizing aerodynamic efficiency for passenger transport, influencing subsequent civil aviation standards.^[64]^[65]^[66] Post-World War II jet aircraft introduced adjustable wing tips to address stability challenges at varying speeds, exemplified by the North American XB-70 Valkyrie bomber prototype in the 1960s, which incorporated folding wing tips that could droop up to 65 degrees. These tips enhanced directional stability and reduced drag by capturing wingtip vortices during supersonic cruise at Mach 3, while also improving low-speed handling by increasing effective span and roll authority without compromising the fixed delta wing's high-speed sweep. The XB-70's innovations in variable tip geometry laid groundwork for adaptive designs in high-performance military aircraft.^[67]

Modern Advancements

In the late 2000s and 2010s, advancements in composite materials revolutionized wingtip design, enabling lighter and more efficient structures. The Boeing 787 Dreamliner, introduced in 2009, exemplifies this shift with its raked wingtips constructed primarily from carbon-fiber-reinforced polymers (CFRP), which provide superior strength-to-weight ratios compared to traditional aluminum alloys. The use of composites in the 787's structure, including raked wingtips, contributes to an overall aircraft weight reduction of approximately 20% relative to similar aluminum designs, enhancing fuel efficiency and range without compromising structural integrity.^[68] Evolutionary wingtip devices, such as blended winglets and sharklets, further improved aerodynamic performance in the 2010s. Aviation Partners developed the split scimitar winglet, a refined design featuring upper and lower extensions that minimize induced drag more effectively than earlier models; this technology was certified for retrofit on the Boeing 737 in 2014 and integrated into variants like the 737 MAX by 2017. These winglets achieve fuel savings of 5-6% over non-winglet configurations by optimizing vortex flow and reducing interference drag, as demonstrated in flight tests and operational data from airlines.^[30] Active control systems emerged in NASA-led research during the 2010s, introducing morphing wingtips equipped with actuators to dynamically adjust geometry during flight. These systems, often using piezoelectric or shape-memory alloys, adapt the wingtip's dihedral or camber to flight conditions, such as takeoff, cruise, or landing, thereby reducing drag by up to 10% through real-time optimization of wingtip vortices. Prototypes tested in wind tunnels and flight simulations confirmed their potential for seamless integration into commercial aircraft, addressing limitations of fixed designs.^[69] With growing emphasis on sustainability in the 2020s, wingtip technologies have been tailored for electric vertical takeoff and landing (eVTOL) vehicles, integrating with distributed electric propulsion systems. Joby Aviation's eVTOL designs, such as the S4 model under development since the mid-2010s, optimize short-span wingtips to balance hover efficiency and forward-flight aerodynamics, minimizing induced drag in compact configurations suited for urban air mobility. This approach leverages electric motors' high power density to enable variable tip geometries that enhance overall energy efficiency, supporting zero-emission operations.^[70]

Specialized Uses

Military Implementations

In military aviation, wing tip adaptations prioritize combat durability, weapon integration, and multi-role versatility for tactical aircraft, enabling enhanced maneuverability and mission flexibility in high-threat environments. Wing tip hardpoints serve as critical mounts for weaponry, particularly tip rails designed to carry air-to-air missiles for rapid deployment in dogfights. The F-16 Fighting Falcon, which entered operational service in the late 1970s, features dedicated wingtip rails that accommodate AIM-9 Sidewinder infrared-guided missiles, providing two such stations for short-range engagements while minimizing drag in clean configurations.^[71] These rails enhance the aircraft's lethality without compromising its agile flight envelope, a design choice that has been standard across F-16 variants for over four decades. Aerial refueling probes are occasionally positioned at wing tips in certain designs to preserve aerodynamic balance and stability during in-flight refueling, reducing lateral oscillations in turbulent conditions. For vertical takeoff and landing (VTOL) applications, wing tip jets integrate propulsion systems directly at the tips to generate lift, often using dedicated engines for hover and transition phases. The experimental EWR VJ 101 from the 1960s utilized four Rolls-Royce RB.145 turbojets in tilting nacelles at the wing tips, supplemented by two fuselage lift engines, to achieve vertical lift and supersonic forward flight, validating tiltjet concepts for potential NATO fighter roles before the program concluded in 1968.^[72] Stealth enhancements incorporate radar-absorbent materials to scatter and absorb radar waves, contributing to the overall reduction in radar cross-section (RCS) for survivability against air defenses. The F-35 Lightning II, achieving initial operational capability in 2015 for the F-35B variant, applies specialized low-observable coatings as part of a comprehensive stealth architecture, enabling the aircraft to evade detection at extended ranges in contested airspace.^[73]

Civilian and Experimental Features

In civilian aviation, wingtips have been adapted for amphibious operations through retractable floats mounted at the tips, enabling seamless transitions between water and land landings. The Consolidated PBY-5A Catalina, introduced in the late 1930s, exemplifies this design, where electrically operated floats fold upward during flight to form the outer wingtips, providing stability on water while maintaining a 104-foot span for efficient cruising.^[74]^[75] This configuration supported diverse roles in search-and-rescue and patrol missions, with the floats ensuring the wingtips remained clear of water during takeoff and landing.^[76] Aerobatic aircraft often incorporate smoke systems to generate visible trails, enhancing spectator visibility and providing pilots with aerodynamic references during airshows. Systems like those on the Extra 300 series, developed in the 1980s, utilize oil injection into the exhaust to release smoke, creating precise vapor trails that highlight maneuvers such as rolls and loops.^[77]^[78]^[79] These setups produce dense, controllable smoke for visual effects without significantly impacting performance.^[79] In gliding, wingtip extensions known as tip sails or winglets extend the effective aerodynamic span, reducing induced drag and improving glide ratios. The Schempp-Hirth Discus, introduced in the 1980s, features optional winglets that increase the effective span by approximately 10%, allowing for better low-speed efficiency and extended flight durations in thermals. This design, with swept-back leading edges on the extensions, enhances overall lift-to-drag ratios, making it a staple in competitive soaring.^[80] Experimental aircraft push wingtip innovations further, integrating lightweight structures with solar panels and sensors for sustained high-altitude missions. The NASA Helios Prototype, flown in 2001, employed an ultra-lightweight flying wing with solar cells covering the entire upper surface, including the tips, to power electric motors for flights exceeding 96,000 feet.^[81] The flexible, carbon-composite tips contributed to the 247-foot span's minimal weight—under 2,000 pounds empty—enabling prolonged endurance testing for atmospheric research.^[82]

References

[1]
Wing Geometry | Glenn Research Center - NASA
Jul 7, 2025 · The ends of the wing are called the wing tips, and the distance from one wing tip to the other is called the span. The shape of the wing, when ...
[2]
Winglets | Glenn Research Center - NASA
Jul 7, 2025 · Winglets are bent-up wing tips that reduce tip vortex strength, making flow more two-dimensional, and can reduce fuel use.Factors of Aerodynamic Drag · Winglets · Effects of Induced Drag · Drag Coefficient
[3]
Vortex Drag - for How Things Fly
Vortex drag is caused by wing tip vortices, which are spirals of air that steal energy, reducing lift and increasing drag.Missing: definition | Show results with:definition
[4]
[PDF] Chapter 5: Aerodynamics of Flight - Federal Aviation Administration
Wingtip vortices are greatest when the generating aircraft is. “heavy, clean, and slow.” This condition is most commonly encountered during approaches or ...
[5]
Aerodynamics of Finite Wings – Introduction to Aerospace Flight ...
The wingtip vortices trail behind the wing, producing a downwash that reduces lift and increases drag. The inherent three-dimensionality of the flow at the wing ...
[6]
Winglets Save Billions of Dollars in Fuel Costs | NASA Spinoff
In 1897, British engineer Frederick W. Lanchester conceptualized wing end-plates to reduce the impact of wingtip vortices, but modern commercial technology for ...
[7]
[PDF] Numerical Analysis and Optimization of Wing-tip Designs
Since there are so many geometric variables that define a wingtip design, it is important to first define the control variables before conducting a parametric ...
[8]
Parts of a Wing - Pilot Institute
Jan 10, 2022 · This section is called the wingtip. The wingtips are the furthest most point of the wing from the aircraft's body. Span. The wingspan of an ...
[9]
4.4.2: Structural elements and functions of the wing
Jun 25, 2024 · A wing consists of two essential parts. The internal wing structure, consisting of spars, ribs, and stringers, and the external wing, which is the skin.
[10]
Introduction to Wing Structural Design - AeroToolbox
The spar caps are responsible for transferring the bending moment generated by the wing into the surrounding structure. When the wing is subjected to a positive ...<|control11|><|separator|>
[11]
6 Common Types of Airplane Wingtips | Blog- Monroe Aerospace
### Summary of Basic Wingtip Shapes
[12]
The Materials Used in the Design of Aircraft Wings - AZoM
Jun 9, 2015 · Steel and aluminium alloys can be used in the manufacture of ribs, whilst composite materials can be used in the design of the wing skin and ...
[13]
[PDF] Chapter 6: Flight Controls - Federal Aviation Administration
The ailerons are attached to the outboard trailing edge of each wing and move in the opposite direction from each other. Ailerons are connected by cables, ...
[14]
Effects of Large Wing-Tip Masses on Oscillatory Stability of Wing ...
An examination of oscillatory stability for a straight-winged airplane with large concentrated wing-tip masses was made using wing-bending and ...
[15]
[PDF] 9/28/04 Initiated By: ACE-100 AC No:23.629-1B Change
Oct 28, 2004 · Prevention of wing flutter is attempted through careful attention to three parameters; wing torsional flexibility, aileron balance, and aileron ...
[16]
None
Summary of each segment:
[17]
Wing Vortices - Centennial of Flight
Creation of vortices. Wing-tip vortices are formed when high-pressure air spills up over the wing tips into the low-pressure space above the wing. Vortices in ...<|separator|>
[18]
Downwash Effects on Lift | Glenn Research Center - NASA
Jul 15, 2024 · Downwash, caused by wing tip vortices, decreases the effective angle of attack, reducing the lift coefficient of the entire wing.Air Pressure · Lift Coefficient · Aspect RatioMissing: wake | Show results with:wake
[19]
Wake Turbulence - Federal Aviation Administration
There are several types of winglets, but their primary function is to increase fuel efficiency by improving the lift-to-drag ratio.
[20]
Aircraft Wake Turbulence - Federal Aviation Administration
Aug 13, 2024 · ATC mitigates wake vortex encounter risk through minimum separation standards between leader aircraft and follower aircraft, as well as ...
[21]
Smoke and Tuft Flow Visualization
Smoke is used to visualize the flow that is away from the surface of the model. Smoke can be used to detect vortices and regions of separated flow.Missing: trails | Show results with:trails
[22]
[PDF] Aviation System Block Upgrades - ICAO
Mar 28, 2013 · how wake separations are applied. 1.2. Baseline. 1.2.1. Wake turbulence separation standards and procedures and associated procedures were.
[23]
Induced Drag Coefficient | Glenn Research Center - NASA
Jul 27, 2023 · The induced drag coefficient Cdi is equal to the square of the lift coefficient Cl divided by the quantity: pi(3.14159) times the aspect ratio AR times an ...
[24]
[PDF] /\352 L Nonlinear Aerodynamics and the Design of Wing Tips
Tests at NASA Langley (Ref. 10) have indicated the potential for reduced drag with highly tapered and swept wing tip planfarms. However, the results remain ...
[25]
Oswald Efficiency Factor - an overview | ScienceDirect Topics
The Oswald efficiency factor is introduced into the induced drag term to align predictions using the drag equation with experimental data, accounting for the ...
[26]
[PDF] Aerodynamic Design of the Hybrid Wing Body Propulsion- Airframe ...
The former is a feature in wing design which deliberately modifies the spanwise lift distribution to reduce the induced drag and to prevent the tip stall from ...
[27]
https://ntrs.nasa.gov/api/citations/19760019075/downloads/19760019075.pdf
[28]
[PDF] Computational Fluid Dynamics Analysis of the Stall Characteristics ...
Stall characteristics of a wing designed based on Prandtl's minimum induced drag solution using the bending moment as the design constraint is presented.
[29]
[PDF] nasa tn d-8260 a design approach and selected wind-tunnel results ...
Secondly, the airfoil should be shaped so that the onset of significant boundary-layer separation on the winglet surface is delayed to the conditions for which.Missing: prevent | Show results with:prevent
[30]
Dr. Richard T. Whitcomb | National Air and Space Museum
In 1952 Whitcomb solved the problem with a design to reduce drag and increase speed without the addition of power. His idea was labeled the 'area rule'. His ...
[31]
This Month in NASA History: Winglets Helped Save an Industry
Jul 22, 2014 · In the 1960s, he created the supercritical airfoil: a unique blunt-edged wing design that delayed drag and increased fuel efficiency. Whitcomb's ...
[32]
Winglet Types | Blended and Split Scimitar - Aviation Partners
The Blended Winglet has a large radius and is designed with a smooth chord variation in the transition area where the wing joins the winglet.
[33]
Airbus's Sharklets Gain EASA Approval | Aviation International News
Dec 3, 2012 · Airbus now expects its Sharklets to produce a fuel savings of roughly 4 percent—better than originally anticipated. “The annual greenhouse gas ...
[34]
Wingtips - an overview | ScienceDirect Topics
The report concluded, “the effect of rake on the lift and drag are so small that considerations of strength and aileron efficiency should govern the wing tip ...
[35]
Lockheed 1049G Super Constellation | The Museum of Flight
For long range operations, the Super G could be fitted with extra wingtip tanks, increasing the fuel capacity by two-thirds more than the original Connie ...
[36]
L1049 Super Constellation - Connie Survivors
Later developments included twin 600-gallon wing tip tanks on civilian L1049G/H's and military early warning radar Super Constellations resulting in an extended ...
[37]
[PDF] notice - NASA Technical Reports Server (NTRS)
Design fuel load contained in wing, tip tanks (if any), and fuselage tanks (if any). V.l.3.6 Minimum Fuel for Weight and Balance* Condition. 1. Piston engine ...
[38]
THE LAV TIP TANK - The Lockheed File - Adastron
LAV's first L-1049G entered service in 1956 so it is possible that it was fitted with surplus tip tanks from TWA's stock. This might explain how the tip tank ...
[39]
[PDF] THEORETICAL ASPECTS AND PRACTICAL US AGE OF ...
The Hoerner wing tip has a thin, round leading edge, a sharp trailing edge, a straight top, and a convex bottom, designed to reduce turbulence and improve ...Missing: Grumman | Show results with:Grumman
[40]
Why Doesn't The Boeing 787 Have Winglets? - Simple Flying
Research by Boeing and NASA found that this design offers greater drag reduction (5.5%) than traditional winglets (3.5-4.5%).
[41]
What you should know about…winglets and wingtips
Jun 27, 2019 · Winglets are upward-pointing wing tips inspired by birds, reducing fuel burn and drag. Wingtips have various shapes, and raked wingtips improve ...<|control11|><|separator|>
[42]
Why Did Airbus Build The A380 Without Winglets? - Simple Flying
Jul 28, 2025 · The A380's large, high-aspect-ratio wings are already designed to reduce drag, allowing the wingtip fences to provide a reduced drag reduction ...
[43]
Wingtip Box & Fence - RUAG
RUAG Aerostructures has been producing the complete wing tip fence & box for the Airbus A380 since 2009.
[44]
[PDF] The effect of folding wingtips on the worst-case gust loads of a ...
Folding wingtips increase aspect ratio, potentially improving performance and gust load alleviation. This study examines the effects of hinge position, ...<|control11|><|separator|>
[45]
Boeing 777X - Commercial aircraft - Liebherr
Folding wing tip actuation · High-lift actuators · Power drive unit and hydraulic motor for leading edge actuation system ...
[46]
How the 777X's folding wing tips work - The Air Current
Oct 5, 2018 · At the tip of the 777X's carbon fiber wings, a hydraulic actuator rotates the tips to their inflight position. ... UTC Aerospace Systems – soon to ...Missing: hinge rotary rams
[47]
[PDF] 777X Rev E - Boeing
The 777-9 Non-Normal Folding Wing Tip operational. Plan outlines a generic airport operations plan for 777-9 for ground maneuvering in the event of a non-normal ...
[48]
Watch: Boeing 777X Folding Wingtip | Aviation Week Network
Share. Guy Norris October 31, 2016. Aviation Week editors recently saw a demonstration of the folding wingtip at Boeing's plant in Everett, Washington.
[49]
[PDF] Numerical Analysis of a Morphing Fairing for Folding Wingtip Joints
Dec 24, 2024 · designed to keep the wingtips straight during cruise showed a 4.2% reduction in wing root bending moment during a 2.5 g manoeuvre load case [103] ...
[50]
[PDF] Engineering Brief 94B, Accommodating the Boeing B-777 Folding ...
This folding wingtip design allows for use of existing airfield infrastructure designed for Airplane Design Group. (ADG) V without special airport operating ...
[51]
Initial exploration of a compliance-based morphing fairing concept ...
This paper introduces a novel design for a compliant fairing to eliminate the gaps present on hinged aerodynamic surfaces such as hinged wingtips.
[52]
Boeing (McDonnell Douglas) F/A-18 Hornet - Military Factory
As with all Navy aircraft, the design featured folding wing sections for improved carrier hangar storage. Fly-By-Wire (FBW) controlling was standard and ...
[53]
NASA Uses Shape Memory Alloys to Fold F-18 Aircraft Wing
The first test condition is from zero to 90 degrees. So from horizontal to vertical. Similar to the way an F18 aircraft folds wing. In this case the highest ...
[54]
[PDF] 777X Airport Compatibility Brochure | Boeing
Since the larger wingspan places the 777X into ICAO Aerodrome Reference Code F, all. 777X models include folding wing tips, allowing the 777X to operate in ...
[55]
Special Conditions: The Boeing Company Model 777-8 and 777-9 ...
May 18, 2018 · Boeing will add folding wingtips to their Model 777-8 and 777-9 airplane wings to maintain Code E gate compatibility when folded during ...
[56]
Why Did Boeing Build The 777X With Folding Wings? - Simple Flying
Jul 30, 2025 · Folding wingtips introduce more moving parts into the aircraft, meaning there are more parts to maintain and break down. Another issue is that ...
[57]
[PDF] Mass Estimation of Folding Wings - HAW Hamburg
May 22, 2024 · Practical Implications – Approximating wing mass increase due to a fold can be estimated easily. The equations can be used in a spreadsheet for ...
[58]
Wing Warping Interactive | Glenn Research Center - NASA
Jun 14, 2023 · Wing warping is twisting wing tips relative to the rest of the wing, achieved by moving the rear portion of the wing via cables and a pedal.Missing: design rounded
[59]
1903 Wright Flyer | National Air and Space Museum
### Summary of Wing Design, Shape of Tips, and Control System
[60]
The Evolution of World War I Aircraft | National Air and Space Museum
Explore some of the most pivotal aircraft from World War I and the technologies that supported them in the air.
[61]
Sopwith F.1 Camel - aircraft investigation info
calculated wing chord (rounded tips): 1.42 [m]. wing aspect ratio : 6.82 ... weight wing/square meter : 3.42 [kg]. weight 4 interplane struts & cabane ...
[62]
[PDF] CASE F_ L COPY - NASA Technical Reports Server (NTRS)
and a winglet with taper ratio of 0.5 and an area reduction of 25 percent. ... Douglas. DC-10, use a different design philosophy. Such aircraft have wings ...
[63]
[PDF] 6. Subsonic Aerodynamics of Airfoils and Wings - Virginia Tech
Mar 9, 2006 · For a straight untwisted, unswept wing, the minimum induced drag corresponds to a taper ratio of about 0.4. However, a tapered wing is more ...
[64]
[PDF] Perspectives on Highly Adaptive or Morphing Aircraft
3. The XB-70's wing tips drooped, providing many benefits. At supersonic conditions the drooped tips improved directional stability and drag through capturing ...
[65]
787 Dreamliner By Design
### Summary of Composite Materials in Boeing 787 Wings and Wingtips
[66]
[PDF] NASA Innovation Fund 2010 Project Elastically Shaped Future Air ...
Oct 8, 2010 · The advantage of wing shaping for drag reduction has been demonstrated by analysis in this study. Wing shaping is a revolutionary ...Missing: wingtip | Show results with:wingtip
[67]
[PDF] Conceptual Design of the Joby S2 Electric VTOL PAV
Jun 16, 2014 · The resulting aircraft design demon- strates the potential of these new electric propulsion technologies to enable viable and attractive new ...
[68]
F-16 Fighting Falcon
### Summary of F-16 Wingtip Hardpoints for AIM-9 Sidewinder Missiles
[69]
F/A-18E/F Super Hornet | NAVAIR
### Summary of Aerial Refueling Probe Location on F/A-18E Super Hornet
[70]
German Jet VTOL: VJ 101C, Do 31, & VAK 191B - AirVectors
Feb 1, 2024 · It seemed conventional enough with its high-mounted swept wing, an RB.230 turbofan with 107 kN (10,900 kgp / 24,000 lbf) thrust under each wing, ...
[71]
Made to Evade: The F-35's Unrivaled Stealth
Feb 12, 2024 · Radar absorbent coating: The gray “paint” on the F-35 reduces and absorbs radar signals. Embedded sensors, weapons, and fuel: Internal sensors ...
[72]
PBY-5A Catalina - Naval History and Heritage Command
One of the most recognized aircraft in the world, the Consolidated PBY Catalina ... floats that folded upward to become wingtips in flight. The overall effect ...
[73]
Consolidated PBY–5a Catalina: Stand up and salute - AOPA
Aug 5, 2014 · When retracted, the electrically operated floats form the wing tips, and their struts blend into the undersides of the wings. A Land-Sea switch ...
[74]
PBY History - The Catalina Preservation Society
Floats to keep the wingtips out of the water on takeoff and landing were retractable, swinging out and upward to morph into the wingtips when the craft was ...
[75]
https://www.aopa.org/news-and-media/all-news/2014/august/pilot/f_pby
[76]
Wingtip vortices made visible with ribbons of white smoke
Apr 26, 2018 · Wingtip vortices are made visible by a smoke system that creates twisting smoke trails, which are circular patterns of rotating air left behind ...Missing: Extra | Show results with:Extra
[77]
Sanders Smoke Technologies, Inc.
Founded by Frank and Ruth Sanders, Sanders Smoke Technologies has been building and selling self-contained smoke generators since 1973.
[78]
Discus-2c - SCHEMPP-HIRTH Flugzeugbau GmbH
Easy to use and numerous possible uses make the Discus-2c the glider of ... Wing span, 15 m, 49.21 ft. Wing area, 10.16 m², 109.36 ft². Aspect ratio, 22.2 ...Missing: sails effective
[79]
[PDF] Helios Prototype - NASA Facts
The two primary goals of the Helios Prototype development are to demonstrate sustained flight at an altitude near 100,000 feet and flying non-stop for at least.
[80]
[PDF] Technical Findings, Lessons Learned, and Recommendations ...
Although the Helios Prototype aircraft was conceived as a very simple aircraft design for high-altitude solar flight, the structural flexibility and the large ...<|control11|><|separator|>