Figure 13-1.  The Piper Super Cub on the left is a popular tailwheel airplane. The airplane on the right is a Mooney M20, which is a  nosewheel (tricycle gear) airplane.  stop a turn that has been started, and it is necessary to apply  an opposite input (opposite rudder) to bring the aircraft back  to straight-line travel. If the initial rudder input is maintained after a turn has been  started, the turn continues to tighten, an unexpected result  for pilots accustomed to a nosewheel. In consequence, it is  common for pilots making the transition between the two  types to experience difficulty in early taxi attempts. As long  as taxi speeds are kept low, however, no serious problems  result, and pilots typically adjust quickly to the technique of  using rudder pressure to start a turn, then neutralizing the  pedals as the turn continues, and finally using an opposite  pedal input to stop the turn and regain straight line travel. Because of this inbuilt instability, the most important lesson  that can be taught in tailwheel airplanes is to taxi and make  turns at slow speeds. A second strong contrast to nosewheel airplanes, tailwheel  aircraft make lift while on the ground any time there is a  relative headwind. The amount of lift obviously depends on  the wind speed, but even at slow taxi speeds, the wings and  ailerons are doing their best to aid in liftoff. This phenomenon  requires care and management, especially during the takeoff  and landing rolls, and is again unexpected by nosewheel pilots  making the transition. On most tailwheel-type airplanes, directional control while  taxiing is facilitated by the use of a steerable tailwheel,  which operates along with the rudder. The tailwheel steering  mechanism remains engaged when the tailwheel is operated  through an arc of about 30° each side of center. Beyond that  limit, the tailwheel breaks free and becomes full swiveling. In  full swivel mode, the airplane can be pivoted within its own  Because of the relative placement of the main gear and the  CG, tailwheel aircraft are inherently unstable on the ground.  As taxi turns are started, the aircraft begins to pivot on one or  the other of the main wheels. From that point, with the CG aft  of that pivot point, the forward momentum of the plane acts  to continue and even tighten the turn without further steering  inputs. In consequence, removal of rudder pressure does not  Proper usage of the rudder pedals is crucial for directional  control while taxiing. Steering with the pedals may be  accomplished through the forces of airflow or propeller  slipstream acting on the rudder surface or through a  mechanical linkage acting through springs to communicate  steering inputs to the tailwheel. Initially, the pilot should taxi  with the heels of the feet resting on the floor and the balls of  the feet on the bottom of the rudder pedals. The feet should  be slid up onto the brake pedals only when it is necessary to  depress the brakes. This permits the simultaneous application  of rudder and brake whenever needed. Some models of  tailwheel airplanes are equipped with heel brakes rather than  toe brakes. As in nosewheel airplanes, brakes are used to slow  and stop the aircraft and to increase turning authority when  tailwheel steering inputs prove insufficient. Whenever used,  brakes should be applied smoothly and evenly. The main landing gear forms the principal support of the  airplane on the ground. The tailwheel also supports the  airplane, but steering and directional control are its primary  functions. With the tailwheel-type airplane, the two main struts  are attached to the airplane slightly ahead of the airplane’s  center of gravity (CG), so that the plane naturally rests in a  nose-high attitude on the triangle created by the main gear and  the tailwheel. This arrangement is responsible for the three  major handling differences between nosewheel and tailwheel  airplanes. They center on directional instability, angle of attack  (AOA), and crosswind weathervaning tendencies. 13-2 Instability Taxiing Angle of Attack Landing Gear