A moving object has different parameters like speed, velocity and acceleration. Speed is the measure of how fat a body travels. Let us understand What is Constant Speed which is a special case of speed. A body in motion has Constant Speed when it travels equal distance in equal intervals of time.
For example if a body travels along a straight line such that it travels 2km in 1 hr and 4 km in 2 hrs i.e. 2 km in 2nd hr also and so on. This means that body has constant speed. An object moving in an orbit also possesses constant speed. Planets revolve around sun with constant spd but varying velocity.
This is because velocity is speed with direction and while moving in orbit the direction of the objects keeps on changing at every instance. So objects moving in an orbit have constant spd but varying velocity or we can say have acceleration as acceleration is rate of change of velocity. Formula for constant spd = distance travelled /time taken. Its unit is metre/second or m/s. Constant spd can be represented by speed time graph by a line parallel to the time axis. This is because at every instant the body has a constant or same value of speed.
A propeller converts power of rotation of an engine into thrust. Power of rotation is known as torque. Hence torque is converted into thrust. Torque can be understood as twisting. Propellers are also used in airplanes. In airplanes const. speed propellers operate as a thrust source which helps in moving the plane in forward direction. The special feature of Constant Speed Propeller (s) is that they maintain rpm of propeller by changing the blade angle.
The capability of a propeller to turn its blade at such an angle that the edges of blades face directly the ambient air flow at 90o is known as feathering. Blades of a propeller are designed as wings but it should work while rotation of hub. Chord line of propellers is imaginary line that is drawn from the center of leading edge to the back portion of propeller.
Blade angle is the angle b/w propeller chord and rotational plane. This is fixed in most of the airplanes. For propellers we consider pitch instead of blade angle. By changing the blade angle of the propeller we can change pitch. An efficient propeller has least amount of slippage and converts more horsepower of engine to thrust. Const. speed propellers adjust the propeller pitch to get maximum efficiency all conditions of flight.