Flying wires
Encyclopedia
The flying wires of an aircraft work in conjunction with other wing
components such as spars
and interplane strut
s to transmit flight loads. Most commonly used on biplane
aircraft they are also used on monoplane
s and triplane
s.
loads whereas the landing wires support the weight of the mainplanes on the ground and as the name suggests, the inertial forces
that are often encountered on landing. Both are sets of diagonal wires within each of the bays defined by the interplane struts. Lift forces distort each bay upwards on its outer edge so the diagonal that runs outwards from bottom to top planes increases in length; thus the flying wires that resist this distortion run along this diagonal and the landing wires along the other.
Flying wires also serve to maintain dihedral and angle of incidence
by lengthening or shortening individual wires using turnbuckle
s or threaded end fittings. The initial setting or in-service adjustment of these angles, usually with the help of a clinometer
and plumb-bob
, is known as 'rigging'. The wires may be lengths of simple stranded cable, aerofoil
sectioned steel or piano wire
. Thinner wires found between the interplane struts are known as incidence wires.
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...
components such as spars
Spar (aviation)
In a fixed-wing aircraft, the spar is often the main structural member of the wing, running spanwise at right angles to the fuselage. The spar carries flight loads and the weight of the wings whilst on the ground...
and interplane strut
Interplane strut
An interplane strut is an aircraft airframe component designed to transmit lift and landing loads between wing panels on biplanes and other aircraft with multi-wing designs. They also maintain the correct angle of incidence for the connected wing panels and are often braced with wires...
s to transmit flight loads. Most commonly used on 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...
aircraft they are also used on monoplane
Monoplane
A monoplane is a fixed-wing aircraft with one main set of wing surfaces, in contrast to a biplane or triplane. Since the late 1930s it has been the most common form for a fixed wing aircraft.-Types of monoplane:...
s and 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:...
s.
Purpose
Strictly the flying wires (or lift wires) are those that carry liftingLift (force)
A fluid flowing past the surface of a body exerts a surface force on it. Lift is the component of this force that is perpendicular to the oncoming flow direction. It contrasts with the drag force, which is the component of the surface force parallel to the flow direction...
loads whereas the landing wires support the weight of the mainplanes on the ground and as the name suggests, the inertial forces
Inertia
Inertia is the resistance of any physical object to a change in its state of motion or rest, or the tendency of an object to resist any change in its motion. It is proportional to an object's mass. The principle of inertia is one of the fundamental principles of classical physics which are used to...
that are often encountered on landing. Both are sets of diagonal wires within each of the bays defined by the interplane struts. Lift forces distort each bay upwards on its outer edge so the diagonal that runs outwards from bottom to top planes increases in length; thus the flying wires that resist this distortion run along this diagonal and the landing wires along the other.
Flying wires also serve to maintain dihedral and angle of incidence
Angle of incidence
Angle of incidence is a measure of deviation of something from "straight on", for example:* in the approach of a ray to a surface, or* the angle at which the wing or horizontal tail of an airplane is installed on the fuselage, measured relative to the axis of the fuselage.-Optics:In geometric...
by lengthening or shortening individual wires using turnbuckle
Turnbuckle
A turnbuckle, stretching screw or bottlescrew is a device for adjusting the tension or length of ropes, cables, tie rods, and other tensioning systems. It normally consists of two threaded eyelets, one screwed into each end of a small metal frame, one with a left-hand thread and the other with a...
s or threaded end fittings. The initial setting or in-service adjustment of these angles, usually with the help of a clinometer
Inclinometer
An inclinometer or clinometer is an instrument for measuring angles of slope , elevation or depression of an object with respect to gravity...
and plumb-bob
Plumb-bob
A plumb-bob or a plummet is a weight, usually with a pointed tip on the bottom, that is suspended from a string and used as a vertical reference line, or plumb-line....
, is known as 'rigging'. The wires may be lengths of simple stranded cable, aerofoil
Airfoil
An airfoil or aerofoil is the shape of a wing or blade or sail as seen in cross-section....
sectioned steel or piano wire
Piano wire
Piano wire, or "music wire", is a specialized type of wire made for use in piano strings, as well as many other purposes. It is made from tempered high-carbon steel, also known as spring steel.-Manufacture and use:...
. Thinner wires found between the interplane struts are known as incidence wires.