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V-tail

V-tail is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand V-tail rather than just read about it. In short: The V-tail or vee-tail (sometimes called a butterfly tail or Rudlicki's V-tail) of an aircraft is an unconventional arrangement of the tail control surfaces that replaces the traditional vertical and horizontal surfaces with two surfaces set in a V-shaped configuration. It is not widely used in aircraft design.

V-tail — main illustration
V-tail — illustration

Key takeaways

  • V-tail belongs to science; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect V-tail to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of V-tail from memory before moving on to harder problems.

Reference excerpt

The V-tail or vee-tail (sometimes called a butterfly tail or Rudlicki's V-tail) of an aircraft is an unconventional arrangement of the tail control surfaces that replaces the traditional vertical and horizontal surfaces with two surfaces set in a V-shaped configuration. It is not widely used in aircraft design. The aft edge of each twin surface is a hinged control surface called a ruddervator, which combines the functions of both a rudder and elevator.

History The V-tail was invented in 1930 by Polish engineer Jerzy Rudlicki and was tested for the first time on a Hanriot HD.28 trainer, modified by Polish aerospace manufacturer Plage and Laśkiewicz in the summer of 1931.

Variants The X-shaped tail surfaces of the experimental Lockheed XFV were essentially a V tail that extended both above and below the fuselage.

Conventional The most popular conventionally V-tailed aircraft that has been mass-produced is the Beechcraft Bonanza Model 35, often known as the V-tail Bonanza or simply V-Tail. Other examples include the Lockheed F-117 Nighthawk stealth attack aircraft and the Fouga CM.170 Magister trainer. The Cirrus Vision SF50 jet is a recent example of a civilian aircraft adopting the V-tail. Some gliders, like the Lehtovaara PIK-16 Vasama, were designed with a V-tail, but the production Vasamas had a cruciform tail.

Inverted The Blohm & Voss P 213 Miniaturjäger was one of the first aircraft to have an inverted V-tail. Unmanned aerial vehicles such as the LSI Amber, General Atomics Gnat and General Atomics MQ-1 Predator would later feature this type of tail. In pusher UAVs, with propeller at the back, downward tail fins can provide yaw stability without interfering with the propeller. The Ultraflight Lazair ultralights, of which over 2,000 were produced, featured an inverted V-tail, which also carried the rear landing gear.

Advantages 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. Light jet aircraft such as the Cirrus Vision SF50, the Eclipse 400, the Sonex SubSonex or larger jet aircraft, such as the Northrop Grumman RQ-4 Global Hawk unmanned aerial drone often have the power plant placed outside the aircraft. 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 military aircraft, V-tails reduce the number of right angles on an aircraft, improving its stealth characteristics.

Disadvantages In the mid-1980s, the Federal Aviation Administration re-assessed the V-tailed 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 taking off and landing on the Fouga CM.170 Magister, which has a relatively short fuselage.

Ruddervators

Ruddervators are the control surfaces on an airplane with a V-tail configuration. They are located at the trailing edge of each of the two airfoils making up the tail of the plane. The first use of ruddervators may have been on the Coandă-1910's X-tail, although there is no proof that the aircraft ever flew. The later Coandă-1911 flew with ruddervators on its X-tail. Later Polish engineer Jerzy Rudlicki designed the first practical ruddervators in 1930, tested on a modified Hanriot HD.28 trainer in 1931. The name is a portmanteau of "rudder" and "elevator." In a conventional aircraft tail configuration, the rudder provides yaw (horizontal) control and the elevator provides pitch (vertical) control. Ruddervators provide the same control effect as conventional control surfaces, but through a more complex control system that actuates the control surfaces in unison. Yaw moving the nose to the left is produced on an upright V tail by moving the pedals left which deflects the left-hand ruddervator down and left and the right-hand ruddervator up and left. The opposite produces yaw to the right. Pitch nose up is produced by moving the control column or stick back which deflects the left-hand ruddervator up and right and the right-hand ruddervator up and left. Pitch nose down is produced by moving the control column or stick forward which induces the opposite ruddervator movements.

See also Cruciform tail Pelikan tail T-tail Twin tail

References

External links

Simple Aerodynamics Of The V-Tail, from "Flying the Beech Bonanza" by Eckalbar, John C

Illustrations

V-tail: 1950 V-tailed B35 still operated by the National Test Pilot School at the Mojave Air and Space Port
1950 V-tailed B35 still operated by the National Test Pilot School at the Mojave Air and Space Port
V-tail: Rear view of the Cirrus Vision SF50's V-tail and engine outlet
Rear view of the Cirrus Vision SF50's V-tail and engine outlet
V-tail: The V-tail of a Belgian Air Force Fouga CM.170 Magister
The V-tail of a Belgian Air Force Fouga CM.170 Magister
V-tail: An Ultraflight Lazair showing its inverted V-tail covered with translucent Tedlar
An Ultraflight Lazair showing its inverted V-tail covered with translucent Tedlar
V-tail: A top-down view of the Northrop YF-23 Gray Ghost prototype fighter jet, showing its distinctive wide V-tail and ruddervators
A top-down view of the Northrop YF-23 Gray Ghost prototype fighter jet, showing its distinctive wide V-tail and ruddervators

Worked examples

Example 1 — a first encounter with V-tail

Start with the simplest possible case. Write down what V-tail claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to V-tail before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about V-tail ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of V-tail

In research
V-tail appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry
Engineering practice reuses V-tail in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom
V-tail is common in secondary-school and first-year university syllabi. It links to neighbouring topics Aircraft tail configurations, Polish inventions, V-tail aircraft, so understanding it makes those chapters shorter.
In everyday life
Look for V-tail outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study V-tail in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what V-tail means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain V-tail out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is V-tail in simple terms?

The V-tail or vee-tail (sometimes called a butterfly tail or Rudlicki's V-tail) of an aircraft is an unconventional arrangement of the tail control surfaces that replaces the traditional vertical and horizontal surfaces with two surfaces set in a V-shaped configuration. It is not widely used in air…

Why does V-tail matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study V-tail?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on V-tail.

Tags

  • Aircraft tail configurations
  • Polish inventions
  • V-tail aircraft

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