Portable Static Thrust Analyser

AIM: To study the Static thrust produced by the electric motor of the RC airplane

Introduction:-Wings give an airplane lift, but they do not drive it forward. In some airplanes, the propeller (turned by an engine/electric motor) drives the plane forward by pushing the air backward. The air, reacting to the action of the propeller, pushes it forward. (For every action, there is an equal and opposite reaction - Newton's Third Law of Motion.) As the propeller is attached to the plane, it pulls the plane through the air. Based on this concept we calculate the static thrust of the airplane by creating the wagon assembly as seen in the diagram below

Apparatus: 1. 2. 3. 4. 5. 6. 7. 8. 9.

Wagon assembly Dc electric out runner motor Radio receiver and transmitter set Electronic speed control Lithium polymer battery Weighing machine Thread Pulley assembly Tachometer

Procedure: • • • • • • • • • • •

The propeller with the motor is mounted on the front assembly of the wagon The motor is connected with lithium polymer battery to run the motor A known weight is kept on the weighing machine and the machine is set to zero using tare button/option on the machine The known weight is connected via thread over a pulley and connected to wagon assembly The motor is powered which in turn turns the propeller The propeller provides the thrust force forward and hence the wagon assembly is pulled forward which increases the tension in the thread connected to weight As a result of the pulling action of the thread the weight raises and weight reduces which is indicated as negative on the weighing machine Thrust=Tension in the rope=weight indicated in the weighing machine On this we determine the thrust produced by the motor of the airplane The experiment is repeated with different propellers and motors On knowing the weight of the airplane the static thrust to weight ratio

Conclusion : The Static thrust to weight ratio and it is directly proportional to the acceleration of the aircraft. An aircraft with a high thrust to weight ratio has high acceleration. For most flight conditions, an aircraft with a high thrust to weight ratio will also have a high value of excess thrust. High excess thrust results in a high rate of climb.