V-tail

In aircraft, a V-tail or Vee-tail (sometimes called a butterfly tail or Rudlicki's V-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 aft edge of each twin surface is a hinged control surface (sometimes called a ruddervator) which combines the functions of both a rudder and elevators. In aircraft, a V-tail or Vee-tail (sometimes called a butterfly tail or Rudlicki's V-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 aft edge of each twin surface is a hinged control surface (sometimes called a ruddervator) which combines the functions of both a rudder and elevators. The V-tail was invented in 1930 by Polish engineer Jerzy Rudlicki and was tested for the first time at the Hanriot H-28 trainer aircraft, modified by a Polish aerospace manufacturer Plage and Laśkiewicz in the summer of 1931. The X-shaped tail surfaces of the experimental Lockheed XFV were essentially a V tail that extended both above and below the fuselage. Despite its advantages, the V-tail has not become popular on aircraft design. The most popular conventionally V-tailed aircraft that was mass-produced is 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 and the Fouga Magister trainer. The Cirrus Vision Jet is a recent example of a civilian aircraft adopting the V-Tail. Some gliders, like PIK-16 Vasama, were designed with a V-tail, but the production Vasamas had a cruciform tail. The Blohm & Voss P 213 Miniaturjäger was one of the first aircraft having an inverted V-tail. Unmanned aerial vehicles such as the Amber, the GNAT and the MQ-1 Predator would later feature this type of tail.The Ultraflight Lazair ultralights, of which over 2000 were produced, featured an inverted V-tail, which also carried the rear landing gear. Ideally, with fewer surfaces than a conventional three-aerofoil tail or a T-tail, the V-tail is lighter and has less wetted surface area, so thus produces less induced and parasitic drag. However, NACA studies indicated that the V-tail surfaces must be larger than simple projection into the vertical and horizontal planes would suggest, such that total wetted area is roughly constant; reduction of intersection surfaces from three to two does, however, produce a net reduction in drag through elimination of some interference drag. In modern day, light jet general aviation aircraft such as the Cirrus Vision, the Eclipse 400 or the unmanned aerial drone Global Hawk often have the power plant 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 increasing wear on the stabilizer, possibly leading to damage over time. In the mid-1980s, the Federal Aviation Administration grounded the Beechcraft Bonanza due to safety concerns. While the Bonanza met the initial certification requirements, it had a history of fatal mid-air breakups during extreme stress, at a rate exceeding the accepted norm. The type was deemed airworthy and restrictions removed after Beechcraft issued a structural modification as an Airworthiness Directive. V-tailed aircraft require longer rear fuselages than aircraft with conventional empennages to prevent yawing. This tendency, called 'snaking', was apparent on Fouga Magister (which has a relatively short fuselage) on taking off and landing.