V-tail

In aircraft, a V-tail (sometimes called a "butterfly tail") is an unconventional arrangement of the tail control surfaces that replaces the traditional fin and horizontal surfaces with two surfaces set in a V-shaped configuration when viewed from the front or rear of the aircraft. The rear of each surface is hinged, and these movable sections, sometimes called ruddervators, combine the tasks of the elevators and rudder.

The arrangement was invented by Polish engineer Jerzy Rudlicki in 1930, and first tested on a modified Hanriot H-28 trainer in 1931.

Design use

The V-tail has not been a popular choice for aircraft manufacturers. The most popular V-tailed aircraft in mass production was the Beechcraft Bonanza Model 35, often known as the "V-tail Bonanza" or simply "V-Tail". Other examples include the F-117 Nighthawk stealth fighter, the Fouga Magister trainer, and the RQ-1 Predator UAV. The X-shaped tail surfaces of the experimental Lockheed XFV were essentially a V tail that extended both above and below the fuselage. Over 2000 Ultraflight Lazair ultralights were produced, all featuring an inverted V-tail.Hunt, Adam & Ruth Merkis-Hunt: "Skeletal Remains", pages 64-70. Kitplanes Magazine, September 2000.]

Advantages

With fewer surfaces than a conventional tail or a T-tail, the V-tail is lighter and produces less drag. In modern day light jet general aviation aircraft such as the Cirrus Jet, Eclipse 400 or the unmanned aerial drone Global Hawk, the power plant is often placed outside the aircraft to protect the passengers and make certification easier. In such cases V-tails are used to avoid placing the vertical stabilizer in the exhaust of the engine, which would disrupt the flow of the exhaust reducing thrust, and wear on the stabilizer, possibly leading to damage over time. ]

Ruddervators have also been used on some airships, such as the US Navy's N class blimps. Accurate pitch trimming of airships can be difficult and this configuration improves clearance beneath the tail.

References