254:
167:, because of the relation between load factor and apparent acceleration of gravity felt on board the aircraft. A load factor of one, or 1 g, represents conditions in straight and level flight, where the lift is equal to the weight. Load factors greater or less than one (or even negative) are the result of maneuvers or wind gusts.
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When the load factor is +1, all occupants of the aircraft feel that their weight is normal. When the load factor is greater than +1 all occupants feel heavier than usual. For example, in a 2 g maneuver all occupants feel that their weight is twice normal. When the load factor is zero, or very
276:
During straight and level flight, the load factor is +1 if the aircraft is flown "the right way up", whereas it becomes −1 if the aircraft is flown "upside-down" (inverted). In both cases the lift vector is the same (as seen by an observer on the ground), but in the latter the vertical axis of the
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acceleration of gravity (i.e. relative to their frame of reference) equal to load factor times the acceleration of gravity. For example, an observer on board an aircraft performing a turn with a load factor of 2 (i.e. a 2 g turn) will see objects falling to the floor at twice the normal
354:
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. downwards.
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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.
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can be designed for much greater load factors, both positive and negative, than conventional aircraft, allowing these vehicles to be used in maneuvers that would be incapacitating for a human pilot.
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the load factor is +2. Again, if the same turn is performed with the aircraft inverted, the load factor becomes −2. In general, in a balanced turn in which the angle of bank is
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to increase by a factor equal to the square root of the load factor. For example, if the load factor is 2, the stall speed will increase by a ratio of
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The load factor, and in particular its sign, depends not only on the forces acting on the aircraft, but also on the orientation of its vertical axis.
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specify the load factor limits within which different categories of aircraft are required to operate without damage. For example, the US
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371:, or in other words it is the component perpendicular to the airflow of the sum of all aerodynamic forces acting on the aircraft.
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Since the load factor is the ratio of two forces, it is dimensionless. However, its units are traditionally referred to as
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Excessive load factors must be avoided because of the possibility of exceeding the structural strength of the aircraft.
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airplanes, are designed so that they can tolerate load factors much higher than the minimum required. For example, the
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small, all occupants feel weightless. When the load factor is negative, all occupants feel that they are upside down.
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is used, it is formally correct to express it using numbers only, as in "a maximum load factor of 4". If the term
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Humans have limited ability to withstand a load factor significantly greater than 1, both positive and negative.
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The maximum load factors, both positive and negative, applicable to an aircraft are usually specified in the
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In turning flight the load factor is normally greater than +1. For example, in a turn with a 60°
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612:"Part 23. Airworthiness Standards: Normal, Utility, Acrobatic, and Commuter Category Airplanes"
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In the definition of load factor, the lift is not simply that one generated by the aircraft's
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Another way to achieve load factors significantly higher than +1 is to pull on the
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units refers to the fact that an observer on board an aircraft will experience an
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airplanes, from −1 to +2.5 (or up to +3.8 depending on design takeoff weight)
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For normal category and commuter category airplanes, from −1.52 to +3.8
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aircraft points downwards, making the lift vector's sign negative.
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656:"Part 29. Airworthiness Standards: Transport Category Rotorcraft"
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Loss of consciousness due to excessive G (also known as blackout)
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585:"Part 25. Airworthiness Standards: Transport Category Airplanes"
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prescribe the following limits (for the most restrictive case):
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634:"Part 27. Airworthiness Standards: Normal Category Rotorcraft"
50:("load") to which the structure of the aircraft is subjected:
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units does not mean that it is dimensionally the same as the
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The fact that the load factor is commonly expressed in
563:"Groundschool - Theory of Flight. Manoeuvring forces"
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For acrobatic category airplanes, from −3.0 to +6.0
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407:For utility category airplanes, from −1.76 to +4.4
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214:is used instead, as in "pulling a 3 g turn".
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265:, during a coordinated turn. Pink force is the
187:. The load factor is strictly non-dimensional.
716:Aerodynamics, Aeronautics and Flight Mechanics
23:Ratio of the lift of an aircraft to its weight
425:family has load factor limits of −10 to +12.
417:However, many aircraft types, in particular
340:{\displaystyle n={\frac {1}{\cos \theta }}.}
217:A load factor greater than 1 will cause the
482:Incapacitation due to excessive negative G
474:Incapacitation due to excessive positive G
711:. A National Flightshop Reprint. Florida.
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678:"Su-26, 29, 31 – Historical background"
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46:and represents a global measure of the
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535:. Pitman Publishing Limited. London
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744:Load Test of Boeing 777 Wing (1995)
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718:. John Wiley & Sons. New York
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249:Positive and negative load factors
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82:{\displaystyle n={\frac {L}{W}},}
680:. Sukhoi Company. Archived from
413:For helicopters, from −1 to +3.5
709:Aerodynamics for Naval Aviators
436:Human perception of load factor
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202:In general, whenever the term
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714:McCormick, Barnes W. (1979).
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257:Variation of the load factor
391:Federal Aviation Regulations
7:
551:McCormick, p. 464–468.
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238:{\displaystyle {\sqrt {2}}}
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387:Civil aviation authorities
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199:acceleration of gravity.
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446:Unmanned aerial vehicles
16:Not to be confused with
181:acceleration of gravity
430:aircraft flight manual
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183:, also indicated with
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765:Aircraft aerodynamics
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18:Passenger load factor
359:Load factor and lift
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261:with the bank angle
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26:In aeronautics, the
707:Hurt, H.H. (1960).
684:on 10 February 2012
115:is the load factor,
746:, boeingimages.com
740:, aerospaceweb.org
738:Bank Angle and G's
399:transport category
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292:is related to the
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171:Load factor and g
152:{\displaystyle W}
130:{\displaystyle L}
108:{\displaystyle n}
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533:Aerodynamics
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529:L. J. Clancy
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760:Aeronautics
219:stall speed
208:load factor
204:load factor
190:The use of
137:is the lift
28:load factor
754:Categories
701:References
419:aerobatic
369:tailplane
329:θ
326:
269:on board.
688:25 March
662:29 March
640:29 March
618:29 March
591:29 March
569:25 March
565:. RA-Aus
531:(1975).
452:See also
352:elevator
196:apparent
40:aircraft
471:Greyout
458:g-force
42:to its
34:of the
30:is the
722:
539:
479:Redout
294:cosine
92:where
48:stress
44:weight
38:of an
658:. FAA
636:. FAA
614:. FAA
587:. FAA
493:Notes
463:G-LOC
32:ratio
720:ISBN
690:2010
664:2010
642:2010
620:2010
593:2010
571:2010
537:ISBN
397:For
365:wing
300:as
36:lift
323:cos
296:of
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601:^
513:^
501:^
432:.
726:.
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666:.
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622:.
595:.
573:.
335:.
319:1
314:=
311:n
298:θ
290:n
286:θ
263:θ
259:n
231:2
212:g
192:g
185:g
177:g
165:g
147:W
125:L
103:n
77:,
72:W
69:L
64:=
61:n
20:.
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