To model aircraft to make movements, it is necessary to apply a force, which is called a pull. Thrust is produced by using propeller , which is spinning its blades throws back airflow, ie flying in the opposite direction. On 3 Newton's law - every action corresponds an equal and opposite reaction - air flow tends to push the propeller in the opposite direction - in the direction of flight. The resulting lift raises the model in the air.
The main geometric parameters of propeller
The diameter of propeller strong> - this is the diameter of the circle described by the ends of the propeller; half diameter - is the radius of the propeller.
Step propeller - the distance traveled by the screw along the axis of revolution. Step propeller can be constant or variable.
The pace of the screw - a distance that model aircraft flying in one revolution of propeller .
The propeller, installed in front of the model, called the tractor propeller. In certain cases, set screws rear wing; this is called a pusher propeller.
Profile propeller - this section of the blade screws on its working parts. The front part of the profile is called the nose and the opposite part - shank. The distance between the most distant points of the nose and the shank is called the width of the profile, and the line connecting these points is called a chord. Maximum distance perpendicular to the chord of the profile is called the thickness profile.
The basic aerodynamic characteristics propeller
The angle of attack: the profile of the angle of the screw to the air flow
The quality of the profile - the ratio of lift to drag ratio, which is obtained when the air flow around the profile of the propeller.
section of the installation angle: the angle of the cross section with respect to the plane of rotation of the propeller
The propeller must be balanced as an unbalanced propeller can cause vibration model. If the screw to put on the line, then the poorly balanced it tends to rotate in the direction of heavy parts. To the screw is in equilibrium, it is necessary to remove excess material.
Balancing propellers only statically, which is sufficient to reduce vibration.
The company The GreenChip offers you to buy propellers for your model aircraft!