Twin tail

A twin tail is a specific type of vertical stabilizer arrangement found on the empennage of some aircraft. Two vertical stabilizers—often smaller on their own than a single conventional tail would be—are mounted at the outside of the aircraft's horizontal stabilizer. This arrangement is also known as an H-tail, as it resembles a capital "H" when viewed from rear.

A special case of twin tail is twin boom tail or double tail where the aft airframe consists of two separate fuselages, "tail booms", which each have a rudder but are usually connected by a single horizontal stabilizer. Examples of this construction are the twin-engined Lockheed P-38 Lightning; Northrop P-61 Black Widow; Focke-Wulf Fw 189; the single jet-engined de Havilland Vampire; cargo-carrying Fairchild C-119 Flying Boxcar and the little known Transavia PL-12 Airtruk.

Design

Separating the control surfaces allows for additional rudder area or vertical surface without requiring a massive single tail. On multi-engine propeller designs twin fin and rudders operating in the propeller slipstream give greater rudder authority and improved control at low airspeeds, and when taxiing. A twin tail can also simplify hangar requirements, give dorsal gunners enhanced firing area, and in some cases reduce the aircraft's weight. It also affords a degree of redundancy—if one tail is damaged, the other may remain functional.

Twin

Twins are two offspring produced by the same pregnancy. Twins can either be monozygotic ("identical"), meaning that they can develop from just one zygote that will then split and form two embryos, or dizygotic ("fraternal"), meaning that they can develop from two different eggs; each are fertilized by separate sperm cells.

In contrast, a fetus which develops alone in the womb is called a singleton, and the general term for one offspring of a multiple birth is multiple.

Statistics

The twin birth rate in the United States rose 76% from 1980 through 2009, from 18.9 to 33.3 per 1,000 births. The Yoruba have the highest rate of twinning in the world, at 45–50 twin sets (or 90–100 twins) per 1,000 live births, possibly because of high consumption of a specific type of yam containing a natural phytoestrogen which may stimulate the ovaries to release an egg from each side.

In Central Africa there are 18–30 twin sets (or 36–60 twins) per 1,000 live births. In Latin America, South Asia, and Southeast Asia, the lowest rates are found; only 6 to 9 twin sets per 1,000 live births. North America and Europe have intermediate rates of 9 to 16 twin sets per 1,000 live births.

Twin (production team)

Twin (sometimes written as TWIN) is a Swedish record production and songwriting team, consisting of Niclas Molinder and Joacim Persson, who are working in the genres of pop, R&B and rock.

Production and songwriting discography

2001

Charlotte Perrelli - Miss Jealousy

2002

Amber - Naked

Da Buzz - Wanna Be with Me

Gloria Gaynor - I Wish You Love

2003

No Angels - Pure

Sophie Monk - Calendar Girl

Play - Replay

Snap! - The Cult of Snap!

S Club 8 - Sundown

Belinda - Belinda

2004

American Juniors - American Juniors

Die Schlümpfe - The Smurfs

Charlotte Perrelli - Gone Too Long

Sandy Mölling - Unexpected

Twin (disambiguation)

A twin is one of two offspring produced in the same pregnancy.

Twin may also refer to:

See also

Tail

The tail is the section at the rear end of an animal's body; in general, the term refers to a distinct, flexible appendage to the torso. It is the part of the body that corresponds roughly to the sacrum and coccyx in mammals, reptiles, and birds. While tails are primarily a feature of vertebrates, some invertebrates including scorpions and springtails, as well as snails and slugs, have tail-like appendages that are sometimes referred to as tails. Tailed objects are sometimes referred to as "caudate" and the part of the body associated with or proximal to the tail are given the adjective "caudal".

Function

Animal tails are used in a variety of ways. They provide a source of locomotion for fish and some other forms of marine life. Many land animals use their tails to brush away flies and other biting insects. Some species, including cats and kangaroos, use their tails for balance; and some, such as New World monkeys and opossums, have what are known as prehensile tails, which are adapted to allow them to grasp tree branches.

Tail (disambiguation)

A tail is the section at the rear end of an animal's body, a distinct, flexible appendage to the torso.

Tail or tails may also refer to:

Science and technology

Entertainment

Other uses

See also

Empennage

The empennage (/ˌɑːmpᵻˈnɑːʒ/ or /ˈɛmpᵻnɪdʒ/), also known as the tail or tail assembly, of most aircraft gives stability to the aircraft, in a similar way to the feathers on an arrow; the term derives from the French for this. Most aircraft feature an empennage incorporating vertical and horizontal stabilising surfaces which stabilise the flight dynamics of yaw and pitch, as well as housing control surfaces.

In spite of effective control surfaces, many early aircraft that lacked a stabilising empennage were virtually unflyable. Even so-called "tailless aircraft" usually have a tail fin (vertical stabiliser). Heavier-than-air aircraft without any kind of empennage (such as the McDonnell Douglas X-36) are rare.

Structure

Structurally, the empennage consists of the entire tail assembly, including the tailfin, the tailplane and the part of the fuselage to which these are attached. On an airliner this would be all the flying and control surfaces behind the rear pressure bulkhead.

The front (usually fixed) section of the tailplane is called the tailplane or horizontal stabiliser and is used to provide pitch stability. The rear section is called the elevator, and is usually hinged to the horizontal stabiliser. The elevator is a movable aerofoil that controls changes in pitch, the up-and-down motion of the aircraft's nose. Some aircraft employ an all-moving stabiliser and elevators in one unit, known as a stabilator or "full-flying stabiliser".