Cruciform tail Pros and Cons

The tail of an aeroplane is known by a variety of names, including empennage and stabilizer. However, we believe the term stabilizer is more appropriate since it more accurately explains the component's function. In addition to stabilizing the aircraft, the stabilizer provides some control over it. An aeroplane's tail contributes to the stability and control of the aircraft in pitch and yaw. 

In order to achieve both stability and control, an aircraft tail can take a number of different forms. Many tail designs feature a horizontal wing-like structure as well as one or more vertical or near-vertical components. These structures are usually referred to as horizontal and vertical stabilizers, even though some designs don't exactly meet this description. Airplane tail designs include but are not limited to, the conventional tail, T-tail, cruciform-tail, dual-tail, triple-tail, V-tail, inverted V-tail, inverted Y-tail, twin-tail, boom-tail, high boom-tail, and multiple-plane tail designs, but there are many more types. 

Conventional tail designs are the most common. The T-tail is an adaptation of the conventional tail design, which has the horizontal stabilizer attached to the top of the vertical stabilizer. As a result of the horizontal stabilizer being positioned on top of the vertical stabilizer, the vertical stabilizer's aerodynamic efficiency is also improved.

Between the traditional and T-tail designs, the cruciform tail is the obvious choice. The horizontal stabilizer is shifted halfway up the vertical stabilizer in the cruciform configuration. The cruciform tail design has the advantage of clearing the tail's aerodynamics away from the engine's wake while requiring less hardening of the vertical tail section than a T-tail design. 

In the past, the dual-tail style, which places two vertical stabilizers at the ends of horizontal stabilizers, was very popular on large flying boats and twin-engine propeller-driven bombers (such as the North American B-25). Depending upon the situation, this configuration may be advantageous because it places the vertical stabilizers in the prop wash of the wing-mounted propellers. Therefore, very strong directional control can be achieved even at low speeds. 

The triple-tail design is an appealing option when the vertical stabilizer height needs to meet specific limits, such as the height of hangar doors. This design uses two vertical stabilizers at the ends of the horizontal stabilizers, and one on the fuselage. 

Aviation designers have used the V-Tail, also known as the "butterfly" tail, only in rare instances, the most notable example being the Beechcraft Bonanza V-35. The concept of horizontal and vertical stabilizers clearly does not apply to the V tail. The idea behind the V-tail design is that two surfaces could do the same job as three in the traditional tail and its variants. 

The inverted Y tail is a regular tail with a pronounced droop in the horizontal stabilizers. The inverted Y tail was utilized on the F-4 Phantom, a McDonnell Company mainstay, to keep the horizontal surfaces out of the wing wake at extreme angles of attack.