The primary purpose of using a "T" tail in aircraft design is to what?

The primary purpose of using a "T" tail in aircraft design is to reduce the effects of slipstream rotation. In conventional tail designs, especially when aircraft have propellers, the airflow from the propeller can cause uneven air distribution over the tail surfaces. This can lead to a phenomenon known as slipstream rotation, which negatively affects stability and control, especially at lower speeds or during takeoff and landing.

A "T" tail design elevates the horizontal stabilizer above the turbulent airflow from the propeller. By positioning the stabilizer in this manner, it can operate in cleaner, undisturbed air, which enhances the effectiveness of the elevators and improves overall aerodynamic performance. This design choice helps maintain better control and stability of the aircraft, making it particularly advantageous for high-wing designs or in aircraft that need to compensate for the rotational forces from the propeller.