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Wing loading

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The Monarch Butterfly has a very low 0.168 kg/m2 wing loading
The McDonnell Douglas MD-11 has a high 837 kg/m2 maximum wing loading

In aerodynamics, wing loading is the total mass of an aircraft or flying animal divided by the area of its wing.[1][a] The stalling speed, takeoff speed and landing speed of an aircraft are partly determined by its wing loading.[2]

The faster an aircraft flies, the more its lift is changed by a change in angle of attack so a smaller wing is less adversely affected by vertical gusts. Consequently, faster aircraft generally have higher wing loadings than slower aircraft in order to avoid excessive response to vertical gusts.[3]

A higher wing loading also decreases maneuverability. The same constraints apply to winged biological organisms.

Range of wing loadings[edit]

Wing loading examples[4]
Aircraft Type Introduction MTOW Wing area kg/m2 lb/sqft
Monarch Butterfly Animal Cenozoic 0.168 0.034
birds[b] Animal Cretaceous 1–20 0.20–4.10[5]
bird flight upper critical limit Animal 25 5.1[6]
Ozone Buzz Z3 MS Paraglider 2010 75–95 kg (165–209 lb) 25.8 m2 (278 sq ft) 2.9–3.7 0.59–0.76[7]
Wills Wing Sport 2 155 Hang glider 2004 94.8–139.8 kg (209–308 lb) 14.4 m2 (155 sq ft) 6.6–9.7 1.4–2.0[8]
Gin Fluid 11 Speed flyer 2010 140 kg 11 m2 (120 sq ft) 12.7 2.6
upper limit Microlift glider 2008 220 kg (490 lb) max. 12.2 m2 (131 sq ft) min.[c] 18 3.7[9]
CAA (UK) regulations microlight wing loading limit 2008 [d] 450 kg (990 lb) max. [e] 18 m2 (190 sq ft) min.[f] 25 5.1[10]
Schleicher ASW 22 Glider 1981 850 kg (1,870 lb) 16.7 m2 (180 sq ft) 50.9 10.4
Piper Warrior General aviation 1960 1,055 kg (2,326 lb) 15.14 m2 (163.0 sq ft) 69.7 14.3
Beechcraft Baron General aviation twin-engine 1960 2,313 kg (5,099 lb) 18.5 m2 (199 sq ft) 125 26
Supermarine Spitfire Fighter (WWII) 1938 3,039 kg (6,700 lb) 22.48 m2 (242.0 sq ft) 135 28
Beechcraft Airliner Airliner (commuter) 1968 4,727 kg (10,421 lb) 25.99 m2 (279.8 sq ft) 182 37
Learjet 31 Business jet 1990 7,031 kg (15,501 lb) 24.57 m2 (264.5 sq ft) 286 59
Mikoyan MiG-23 Fighter (variable-geometry) 1970 17,800 kg (39,200 lb) 34.16–37.35 m2 (367.7–402.0 sq ft) 477–521 98–107
Lockheed F-104 Starfighter Fighter (multi-role) 1958 13,166 kg (29,026 lb) 18.22 m2 (196.1 sq ft) 722.6 148.0
General Dynamics F-16 Fighter (multi-role) 1978 19,200 kg (42,300 lb) 27.87 m2 (300.0 sq ft) 688.9 141.1
McDonnell Douglas F-15 Eagle Fighter (air superiority) 1976 30,845 kg (68,002 lb) 56.5 m2 (608 sq ft) 546 112
Mikoyan-Gurevich MiG-25 Fighter (Interceptor) 1970 36,720 kg (80,950 lb) 61.4 m2 (661 sq ft) 598 122
Lockheed SR-71 Blackbird Strategic Reconnaissance Aircraft 1966 68,946 kg (152,000 lb) 170 m2 (1,800 sq ft) 406 83
Fokker F27 Airliner (turboprop) 1958 19,773 kg (43,592 lb) 70 m2 (750 sq ft) 282 58
Fokker F28 Fellowship Airliner (regional jet) 1969 33,000 kg (73,000 lb) 78.97 m2 (850.0 sq ft) 418 86
Boeing 737-400 Airliner (Narrow-body) 1984 62,820 kg (138,490 lb) 91.04 m2 (979.9 sq ft) 690 140
Boeing 737-900ER Airliner (Narrow-body) 2007 85,139 kg (187,699 lb) 124.6 m2 (1,341 sq ft) 683 140
Airbus A321XLR Airliner (Narrow-body) 2024 (est) 101,015 kg (222,700 lb) 122.4 m2 (1,318 sq ft) 825 169
Boeing 767-300ER[11] Airliner (Wide-body) 1982 181,437 kg (400,000 lb) 283.3 m2 (3,049 sq ft) 640 130
Concorde Airliner (supersonic) 1976 187,000 kg (412,000 lb) 358.2 m2 (3,856 sq ft) 522 107
Rockwell B-1B Lancer Bomber (variable-geometry) 1983 148,000 kg (326,000 lb) 181.2 m2 (1,950 sq ft) 818 168
McDonnell Douglas MD-11[11] Airliner (wide-body) 1990 283,720 kg (625,500 lb) 338.9 m2 (3,648 sq ft) 837 171
Boeing 777-300ER Airliner (wide-body) 2004 351,533 kg (774,998 lb) 436.8 m2 (4,702 sq ft) 805 165
Airbus A340-500/600[11] Airliner (wide-body) 2002 365,000 kg (805,000 lb) 437.3 m2 (4,707 sq ft) 835 171
Boeing 747-400[11] Airliner (wide-body) 1988 396,830 kg (874,860 lb) 525 m2 (5,650 sq ft) 756 155
Airbus A380 Airliner (wide-body) 2007 575,000 kg (1,268,000 lb) 845 m2 (9,100 sq ft) 680 140

Effect on performance[edit]

Wing loading is a useful measure of the stalling speed of an aircraft. Wings generate lift owing to the motion of air around the wing. Larger wings move more air, so an aircraft with a large wing area relative to its mass (i.e., low wing loading) will have a lower stalling speed. Therefore, an aircraft with lower wing loading will be able to take off and land at a lower speed (or be able to take off with a greater load). It will also be able to turn at a greater rate.

Effect on takeoff and landing speeds[edit]

The lift force L on a wing of area A, traveling at true airspeed v is given by


where ρ is the density of air and CL is the lift coefficient. The lift coefficient is a dimensionless number which depends on the wing cross-sectional profile and the angle of attack.[12] At steady flight, neither climbing nor diving, the lift force and the weight are equal. With L/A = Mg/A =WSg, where M is the aircraft mass, WS = M/A the wing loading (in mass/area units, i.e. lb/ft2 or kg/m2, not force/area) and g the acceleration due to gravity, that equation gives the speed v through[13]


As a consequence, aircraft with the same CL at takeoff under the same atmospheric conditions will have takeoff speeds proportional to . So if an aircraft's wing area is increased by 10% and nothing else is changed, the takeoff speed will fall by about 5%. Likewise, if an aircraft designed to take off at 150 mph grows in weight during development by 40%, its takeoff speed increases to = 177 mph.

Some flyers rely on their muscle power to gain speed for takeoff over land or water. Ground nesting and water birds have to be able to run or paddle at their takeoff speed before they can take off. The same is true for a hang glider pilot, though they may get assistance from a downhill run. For all these, a low WS is critical, whereas passerines and cliff dwelling birds can get airborne with higher wing loadings.

Effect on turning performance[edit]

To turn, an aircraft must roll in the direction of the turn, increasing the aircraft's bank angle. Turning flight lowers the wing's lift component against gravity and hence causes a descent. To compensate, the lift force must be increased by increasing the angle of attack by use of up elevator deflection which increases drag. Turning can be described as 'climbing around a circle' (wing lift is diverted to turning the aircraft) so the increase in wing angle of attack creates even more drag. The tighter the turn radius attempted, the more drag induced; this requires that power (thrust) be added to overcome the drag. The maximum rate of turn possible for a given aircraft design is limited by its wing size and available engine power: the maximum turn the aircraft can achieve and hold is its sustained turn performance. As the bank angle increases so does the g-force applied to the aircraft, this having the effect of increasing the wing loading and also the stalling speed. This effect is also experienced during level pitching maneuvers.[14]

Load factor varying with altitude at 50 or 100 lb/sq ft

As stalling is due to wing loading and maximum lift coefficient at a given altitude and speed, this limits the turning radius due to maximum load factor. At Mach 0.85 and 0.7 lift coefficient, a wing loading of 50 lb/sq ft (240 kg/m2) can reach a structural limit of 7.33 g up to 15,000 feet (4,600 m) and then decreases to 2.3 g at 40,000 feet (12,000 m). With a wing loading of 100 lb/sq ft (490 kg/m2) the load factor is twice smaller and barely reaches 1g at 40,000 feet.[15]

Aircraft with low wing loadings tend to have superior sustained turn performance because they can generate more lift for a given quantity of engine thrust. The immediate bank angle an aircraft can achieve before drag seriously bleeds off airspeed is known as its instantaneous turn performance. An aircraft with a small, highly loaded wing may have superior instantaneous turn performance, but poor sustained turn performance: it reacts quickly to control input, but its ability to sustain a tight turn is limited. A classic example is the F-104 Starfighter, which has a very small wing and high 723 kg/m2 (148 lb/sq ft) wing loading.

At the opposite end of the spectrum was the large Convair B-36: its large wings resulted in a low 269 kg/m2 (55 lb/sq ft) wing loading that could make it sustain tighter turns at high altitude than contemporary jet fighters, while the slightly later Hawker Hunter had a similar wing loading of 344 kg/m2 (70 lb/sq ft). The Boeing 367-80 airliner prototype could be rolled at low altitudes with a wing loading of 387 kg/m2 (79 lb/sq ft) at maximum weight.

Like any body in circular motion, an aircraft that is fast and strong enough to maintain level flight at speed v in a circle of radius R accelerates towards the center at . That acceleration is caused by the inward horizontal component of the lift, , where is the banking angle. Then from Newton's second law,

Solving for R gives

The lower the wing loading, the tighter the turn.

Gliders designed to exploit thermals need a small turning circle in order to stay within the rising air column, and the same is true for soaring birds. Other birds, for example those that catch insects on the wing also need high maneuverability. All need low wing loadings.

Effect on stability[edit]

Wing loading also affects gust response, the degree to which the aircraft is affected by turbulence and variations in air density. A small wing has less area on which a gust can act, both of which serve to smooth the ride. For high-speed, low-level flight (such as a fast low-level bombing run in an attack aircraft), a small, thin, highly loaded wing is preferable: aircraft with a low wing loading are often subject to a rough, punishing ride in this flight regime. The F-15E Strike Eagle has a wing loading of 650 kilograms per square metre (130 lb/sq ft) (excluding fuselage contributions to the effective area), whereas most delta wing aircraft (such as the Dassault Mirage III, for which WS = 387 kg/m2) tend to have large wings and low wing loadings.[citation needed]

Quantitatively, if a gust produces an upward pressure of G (in N/m2, say) on an aircraft of mass M, the upward acceleration a will, by Newton's second law be given by


decreasing with wing loading.

Effect of development[edit]

A further complication with wing loading is that it is difficult to substantially alter the wing area of an existing aircraft design (although modest improvements are possible). As aircraft are developed they are prone to "weight growth"—the addition of equipment and features that substantially increase the operating mass of the aircraft. An aircraft whose wing loading is moderate in its original design may end up with very high wing loading as new equipment is added. Although engines can be replaced or upgraded for additional thrust, the effects on turning and takeoff performance resulting from higher wing loading are not so easily reconciled.

Water ballast use in gliders[edit]

Modern gliders often use water ballast carried in the wings to increase wing loading when soaring conditions are strong. By increasing the wing loading the average speed achieved across country can be increased to take advantage of strong thermals. With a higher wing loading, a given lift-to-drag ratio is achieved at a higher airspeed than with a lower wing loading, and this allows a faster average speed across country. The ballast can be ejected overboard when conditions weaken or prior to landing.

Design considerations[edit]

Fuselage lift[edit]

The F-15E Strike Eagle has a large relatively lightly loaded wing

A blended wing-fuselage design such as that found on the General Dynamics F-16 Fighting Falcon or Mikoyan MiG-29 Fulcrum helps to reduce wing loading; in such a design the fuselage generates aerodynamic lift, thus improving wing loading while maintaining high performance.

Variable-sweep wing[edit]

Aircraft like the Grumman F-14 Tomcat and the Panavia Tornado employ variable-sweep wings. As their wing area varies in flight so does the wing loading (although this is not the only benefit). When the wing is in the forward position takeoff and landing performance is greatly improved.[16]


Like all aircraft flaps, Fowler flaps increase the camber and hence the maximum value of lift coefficient (CLmax) lowering the landing speed. They also increase wing area, decreasing the wing loading, which further lowers the landing speed.[17]

High lift devices such as certain flaps allow the option of smaller wings to be used in a design in order to achieve similar landing speeds compared to an alternate design using a larger wing without a high lift device. Such options allow for higher wing loading in a design. This may result in beneficial features, such as higher cruise speeds or a reduction in bumpiness at high speed low altitude flight (the latter feature is very important for close air support aircraft roles). For instance, Lockheed's Starfighter uses internal Blown flaps to achieve a high wing loading design (723 kg/m²) which allows it a much smoother low altitude flight at full throttle speeds compared to low wing loading delta designs such as the Mirage 2000 or Mirage III (387 kg/m²). The F-16 which has a relatively high wing loading of 689 kg/m² uses leading-edge extensions to increase wing lift at high angles of attack.

See also[edit]



  1. ^ "Wing Loading Definition". Merriam Webster.
  2. ^ a b "Chapter 11: Aircraft Performance". Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C ed.). Federal Aviation Administration. 17 July 2023. pp. 8–9.
  3. ^ Wragg, David W. (1973). A Dictionary of Aviation (first ed.). Osprey. p. 281. ISBN 9780850451634.
  4. ^ Hendrik Tennekes (2009). The simple science of Flight: From Insects to Jumbo Jets. MIT Press. ISBN 978-0-262-51313-5., "Figure 2: The great flight diagram".
  5. ^ Thomas Alerstam, Mikael Rosén, Johan Bäckman, Per G. P Ericson, Olof Hellgren (17 July 2007). "Flight Speeds among Bird Species: Allometric and Phylogenetic Effects". PLOS Biology. 5 (8): e197. doi:10.1371/journal.pbio.0050197. PMC 1914071. PMID 17645390.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  6. ^ Meunier, K. Korrelation und Umkonstruktionen in den Größenbeziehungen zwischen Vogelflügel und Vogelkörper-Biologia Generalis 1951: pp. 403-443. [Article in German]
  7. ^ Gérard Florit (23 January 2016). "Ozone Buzz Z3". P@r@2000.
  8. ^ "Sport 2 / 2C". Wills Wing.
  9. ^ "Sporting Code Section 3: Gliding". Fédération Aéronautique Internationale. 12 October 2016.
  10. ^ "Microlights". UK Civil Aviation Authority. or a stalling speed at the maximum weight authorised not exceeding 35 knots calibrated speed
  11. ^ a b c d Lloyd R. Jenkinson; Paul Simpkin; Darren Rhodes (30 July 1999). "Aircraft Data File". Civil Jet Aircraft Design. Elsevier Limited.
  12. ^ Anderson, 1999 p. 58
  13. ^ Anderson, 1999 pp. 201–3
  14. ^ Spick, 1986. p. 24.
  15. ^ Laurence K. Loftin Jr. (1985). "Chapter 11 - Aircraft Maneuverability". Quest for Performance - The Evolution of Modern Aircraft. NASA Scientific and Technical Information Branch.
  16. ^ Spick, 1986. pp. 84–87.
  17. ^ Anderson 1999, pp. 30–1



  1. ^ For aircraft, this includes area of ailerons.[2]
  2. ^ 138 species from 10 g to 10 kg, from small passerines to swans and cranes
  3. ^ at max weight
  4. ^ legislation enacted
  5. ^ for a two seat landplane
  6. ^ at max weight

External links[edit]