Wing loading

The wing loading of a wing results from the mass of a missile divided by the wing area : ${\displaystyle B}$ ${\displaystyle m}$ ${\displaystyle A}$

${\displaystyle B={\frac {m}{A}}}$.

If the wing is not a rectangle , it must be considered as an integral over the span : ${\displaystyle b}$

${\displaystyle B={\frac {m}{\int \limits _{-{\frac {b}{2}}}^{+{\frac {b}{2}}}l(y)\,dy}}}$

or with right / left symmetrical wings

${\displaystyle B={\frac {m}{2\,\int \limits _{0}^{+{\frac {b}{2}}}l(y)\,dy}}}$.

The wing loading of the wing and the lift coefficient determine the (minimum) airspeed v _S or v _S0 . That is to say, an aircraft with a high wing loading needs a high speed, one with a lower wing loading needs a lower speed. Therefore, a reduction in wing loading corresponds to an optimization for slow flight and vice versa. Hydrofoils with a high wing loading usually have an arrangement of lift aids to simplify take-off and landing. For example, with Fowler flaps (in addition to the increased setting angle ) the wing area can be enlarged and the wing loading reduced.

In gliders , the wing loading can be varied in flight via the mass of the aircraft. For this purpose, ballast in the form of water is filled into special tanks that are built into the wing before take-off . This has the advantage that in weather conditions with strong thermals the speed polar enables faster gliding flights with less self-sinking due to the higher wing loading . As soon as the thermal subsides, water can be drained off, which enables an easier ascent, due to the then reduced sinking, in weak thermal.

The wing loading in some versions is also designed to be variable in flight over the wing surface. This concerns v. a. Aircraft equipped with swivel wings .

Aircraft categories

• Model airplanes and ultra-light gliding devices have a wing loading of around 2 to 10 kg / m².
• Paragliders around 3 to 4 kg / m².
• Parachutes around 4.5 to 10 kg / m² (high-performance parachutes up to 15 kg / m²).
• Delta glider around 7 to 8 kg / m².
• Gliders around 30 to 60 kg / m².
• Small aircraft (motorized) around 80 to 110 kg / m².
• Propeller-driven passenger aircraft around 100 to 200 kg / m².
• Fighter jets around 300 to 500 kg / m².
• Jet-propelled passenger aircraft 300 to 800 kg / m².
• Airbus A400M with a maximum take-off weight of 637 kg / m².
• MD-11 F with a maximum take-off weight of 844 kg / m².