: 398 When the load factor is negative, all occupants feel that they are upside down. When the load factor is zero, or very small, all occupants feel weightless. For example, in a 2 g maneuver all occupants feel that their weight is twice normal. When the load factor is greater than +1 all occupants feel heavier than usual. When the load factor is +1, all occupants of the aircraft feel that their weight is normal. The maximum load factors, both positive and negative, applicable to an aircraft are usually specified in the aircraft flight manual. For example, the Sukhoi Su-26 family has load factor limits of −10 to +12. However, many aircraft types, in particular aerobatic airplanes, are designed so that they can tolerate load factors much higher than the minimum required. For acrobatic category airplanes, from −3.0 to +6.0.For utility category airplanes, from −1.76 to +4.4.For normal category and commuter category airplanes, from −1.52 to +3.8.For transport category airplanes, from −1 to +2.5 (or up to +3.8 depending on design takeoff weight).For example, the US Federal Aviation Regulations prescribe the following limits (for the most restrictive case): Design standards Įxcessive load factors must be avoided because of the possibility of exceeding the structural strength of the aircraft.Ĭivil aviation authorities specify the load factor limits within which different categories of aircraft are required to operate without damage. The lift in the load factor is also intended as having a sign, which is positive if the lift vector points in, or near the same direction as the aircraft's vertical axis, or negative if it points in, or near the opposite direction. In the definition of load factor, the lift is not simply that one generated by the aircraft's wing, instead it is the vector sum of the lift generated by the wing, the fuselage and the tailplane, : 395 or in other words it is the component perpendicular to the airflow of the sum of all aerodynamic forces acting on the aircraft. N = L W, Īnother way to achieve load factors significantly higher than +1 is to pull on the elevator control at the bottom of a dive, whereas strongly pushing the stick forward during straight and level flight is likely to produce negative load factors, by causing the lift to act in the opposite direction to normal, i.e. In aeronautics, the load factor is the ratio of the lift of an aircraft to its weight : § 5.22 and represents a global measure of the stress ('load') to which the structure of the aircraft is subjected: Ratio of the lift of an aircraft to its weight

Negative g force r