Stagger (aviation)
Encyclopedia
In aviation
stagger refers to the horizontal
positioning of a biplane
, triplane
, or multiplane's wing
s in relation to one another.
An aircraft is said to have positive stagger, or simply stagger, when the upper wing is positioned forward of the lower (bottom) wing, such as the de Havilland Tiger Moth
or Stearman. Conversely, an aeroplane is said to have negative stagger in unusual cases where the upper wing is positioned behind the lower wing, as in the Sopwith Dolphin or Beech Model 17 Staggerwing. An aircraft with the wings positioned directly above each other is said to have unstaggered wings, as in the Sopwith Cuckoo
or Vickers Vildebeest
.
Positive stagger is by far the most common, as this positioning of the upper wing(s) allows better visibility for the crew as well as increased aircraft longitudinal stability
, aerodynamic efficiency and maximum lift.
Aviation
Aviation is the design, development, production, operation, and use of aircraft, especially heavier-than-air aircraft. Aviation is derived from avis, the Latin word for bird.-History:...
stagger refers to the horizontal
Horizontal plane
In geometry, physics, astronomy, geography, and related sciences, a plane is said to be horizontal at a given point if it is perpendicular to the gradient of the gravity field at that point— in other words, if apparent gravity makes a plumb bob hang perpendicular to the plane at that point.In...
positioning of a biplane
Biplane
A biplane is a fixed-wing aircraft with two superimposed main wings. The Wright brothers' Wright Flyer used a biplane design, as did most aircraft in the early years of aviation. While a biplane wing structure has a structural advantage, it produces more drag than a similar monoplane wing...
, triplane
Triplane
A triplane is a fixed-wing aircraft equipped with three vertically-stacked wing planes. Tailplanes and canard foreplanes are not normally included in this count, although they may occasionally be.-Design principles:...
, or multiplane's wing
Wing
A wing is an appendage with a surface that produces lift for flight or propulsion through the atmosphere, or through another gaseous or liquid fluid...
s in relation to one another.
An aircraft is said to have positive stagger, or simply stagger, when the upper wing is positioned forward of the lower (bottom) wing, such as the de Havilland Tiger Moth
De Havilland Tiger Moth
The de Havilland DH 82 Tiger Moth is a 1930s biplane designed by Geoffrey de Havilland and was operated by the Royal Air Force and others as a primary trainer. The Tiger Moth remained in service with the RAF until replaced by the de Havilland Chipmunk in 1952, when many of the surplus aircraft...
or Stearman. Conversely, an aeroplane is said to have negative stagger in unusual cases where the upper wing is positioned behind the lower wing, as in the Sopwith Dolphin or Beech Model 17 Staggerwing. An aircraft with the wings positioned directly above each other is said to have unstaggered wings, as in the Sopwith Cuckoo
Sopwith Cuckoo
-See also:-References:*Davis, Mick. Sopwith Aircraft. Ramsbury, Marlborough, Wiltshire: Crowood Press, 1999. ISBN 1-86126-217-5.*Layman, R.D. Naval Aviation In The First World War: Its Impact And Influence. London: Caxton, 2002. ISBN 1-84067-314-1....
or Vickers Vildebeest
Vickers Vildebeest
The Vickers Vildebeest and the similar Vickers Vincent were two very large two- to three-seat single-engined British biplanes designed and built by Vickers and used as a light bomber, torpedo bomber and in the army cooperation roles...
.
Measurement
The value sometimes expressed as a distance, s say, but it may also be written as a fraction or percentage of the 'gap' (distance g between wings), ie s/g. It may also be presented as an angle equal to tan−1(s/g). The Gloster TSR.38 had a stagger of 0.91 m and a gap of 2.0 m, so the stagger might be written as 0.91 m, 0.455, 45.5% or 24.5°. s is the distance from the leading edge of the upper wing along its chord to the point of intersection of the chord with a line drawn perpendicularly to the chord of the upper wing at the leading edge of the lower wing, all lines being drawn in a plane parallel to the plane of symmetry.Effects
As a general rule, there is a tendency for the upper wing to contribute a greater proportion of the total lift than the lower with positive stagger, and less with negative stagger. Increase in positive stagger also tends to move the centre of lift forward on the upper wing and backward on the lower wing. When unstaggered, the centres of lift for upper and lower wings are almost coincidental.Positive stagger is by far the most common, as this positioning of the upper wing(s) allows better visibility for the crew as well as increased aircraft longitudinal stability
Flight dynamics
Flight dynamics is the science of air vehicle orientation and control in three dimensions. The three critical flight dynamics parameters are the angles of rotation in three dimensions about the vehicle's center of mass, known as pitch, roll and yaw .Aerospace engineers develop control systems for...
, aerodynamic efficiency and maximum lift.