Aircraft Construction

Antiservo tab Stabilator pivot point Figure 3-11. Stabilator components. Landing Gear The landing gear is the principal support of the airplane when parked, taxiing, taking off, or landing. The most common type of landing gear consists of wheels, but airplanes can also be equipped with floats for water operations or skis for landing on snow. [Figure 3-12] Wheeled landing gear consists of three wheels—two main wheels and a third wheel positioned either at the front or rear of the airplane. Landing gear with a rear mounted wheel is called conventional landing gear. Airplanes with conventional landing gear are sometimes referred to as tailwheel airplanes. When the third wheel is located on the nose, it is called a nosewheel, and the design is referred to as a tricycle gear. A steerable nosewheel or tailwheel permits the airplane to be controlled throughout all operations while on the ground. Most aircraft are steered by moving the rudder pedals, whether nosewheel or tailwheel. Additionally, some aircraft are steered by differential braking. The Powerplant The powerplant usually includes both the engine and the Figure 3-12. Types of landing gear: floats (top), skis (middle), and wheels (bottom). propeller. The primary function of the engine is to provide the power to turn the propeller. It also generates electrical is a rotating airfoil that produces thrust through aerodynamic power, provides a vacuum source for some flight instruments, action. A high-pressure area is formed at the back of the and in most single-engine airplanes, provides a source of propeller’s airfoil, and low pressure is produced at the face of heat for the pilot and passengers. [Figure 3-13] The engine the propeller, similar to the way lift is generated by an airfoil is covered by a cowling, or a nacelle, which are both types used as a lifting surface or wing. This pressure differential of covered housing. The purpose of the cowling or nacelle develops thrust from the propeller, which in turn pulls the is to streamline the flow of air around the engine and to help airplane forward. Engines may be turned around to be pushers cool the engine by ducting air around the cylinders. with the propeller at the rear. The propeller, mounted on the front of the engine, translates There are two significant factors involved in the design the rotating force of the engine into thrust, a forward acting of a propeller that impact its effectiveness. The angle of a force that helps move the airplane through the air. A propeller 3-7