A radio controlled aircraft (model) is controlled remotely by a hand held transmitter & receiver within the aircraft. The receiver controls the corresponding servos that moves the control surfaces based on the position of joystick on the transmitter, which in turn affect the orientation of the plane.
Essentially there are four aerodynamic forces that act on an airplane in flight; these are lift, drag, thrust & weight. In simple words, 1. Drag- it is the resistance of air molecules hitting the airplanes ( the backward force). 2. Thrust- it is the power of airplane’s engine( the forward forces). 3. Lift is the upward forces & weight is the downward forces. Thrust is generated by the airplane’s engine( propeller or jet), weight is created by the natural force on gravity upon the airplane & drag comes from friction as the plane moves through air molecules. Drag is also a reaction to the lift, & this lift must be generated by airplane in flight. This is done by the wings of the airplane.
First of all choose the material for the body- 1. Balsa wood – soft and light, easy to work on, Available in strips, most widely used in air modeling. 2. Thermocole / foam- choose high density thermocole(HDT) it should be very light
Then we need propeller( fixed pitch or variable pitch). Generally variable pitch propeller are used for small motors or for reverse flying. variable pitch Fixed Pitch
Next we need battery and servos. Functions of servos is to move surface of plane & also provide turning capabilities of plane.
RC airplane can be used as- 1. Weather survey 2. Defense or military services
Planes fly by the virtue of Bernoulli principle on their wings. Air being pushed under the wings only accounts for a small portion of the lift forces that make an airplane fly. The real forces results from the partial vaccum created above the wings (Bernoulli's principle). To get the Bernoulli effect, the wings must expose a larger surfaces on top than below the wing. Second we need to maintain a flow of air over and under the wings. This is the job of the engine, which pulls the plane & its wings forward, using a propeller.
The remote control, or RC, transmitter sends signals to a receiver on the airplane. Each transmitter has its own signal so that the signals from the planes don't interfere with each other. The receiver is attached to several control motors called servos, and a battery pack to provide power. The receiver sends signals to the servos based on the position of the transmitter stick. These signals tell each servo precisely what position to move to. A cross section of a typical airplane wing will show the top surface to be more curved than the bottom surface. This shaped profile is called an 'airfoil' (or 'aerofoil') and the shape exists because it's long been proven (since the dawn of flight) that an airfoil generates significantly more lift than opposing drag i.e. it's very efficient at generating lift.
During flight air naturally flows over and beneath the wing and is deflected upwards over the top surface and downwards beneath the lower surface. Any difference in deflection causes a difference in air pressure.
RC planes have several controls, each with a different surface. The rudder steers the plane, the ailerons cause it to bank left and right, the flaps increase and decrease lift, the elevators angle the nose up and down, and the motor controls the power. Each part is attached to the servo by a small control arm which moves the control as the servo turns. To understand how each works upon the airplane, imagine 3 lines (axis- the blue dash line in picture) running through the plane. One runs through the centre of the fuselage from nose to tail (longitudinal axis), one runs from side to side (lateral axis) and the other runs vertically (vertical axis). All 3 axis pass through the Centre of Gravity (CG), the airplane's crucial point of balance.