Stabilizer (aircraft) - Combined Longitudinal - Directional Stabilization and Control

Directional Stabilization and Control

On some aircraft, horizontal and vertical stabilizers are combined in a pair of surfaces named V-tail. In this arrangement, two stabilizers (fins and rudders) are mounted at 100 - 120° to each other, giving a larger horizontal projected area than vertical one as in the majority of conventional tails. The moving control surfaces are then named ruddervators. The V-tail thus acts both as a yaw and pitch stabilizer.

Although it may seem that the V-tail configuration can result in a significant reduction of the tail wetted area, it suffers from an increase in control-actuation complexity, as well as complex and detrimental aerodynamic interaction between the two surfaces. This often results in an upsizing in the total area that reduces or negates the original benefit. The Beechcraft Bonanza light aircraft was originally designed with a V-tail.

Others combined layouts exist. The General Atomics MQ-1 Predator unmanned aircraft has an inverted V-tail; while the LearAvia Lear Fan had a Y-tail. All twin tail arrangements with a tail dihedral angle will provide a combination of longitudinal and directional stabilization.