Propeller Thrust

1. Propeller Thrust Hiram Gonzalez, Alphonse Sims Kate Menees, Chris Davis, Carolyn Hawk

2. The Objective Use Lab view Instrument to measure the thrust from different size propellers. Find a way to put different size propellers on a motor.

3. How lab view will work We need to find several different variables: Thrust load coefficient, power coefficient, size of the propeller, speed of the motor.

4. What is in Lab View Converting a volt reading from the resistor into Newtons. The distance from the resistor to the pivot point. Distance from the motor to the pivot point.

5. How We Get From Volts to Newtons The resistor will show a change in voltage as the beam tilts. Then we will use the fish scale hooked to the vertical beam to find the pounds displaced. After plotting those numbers on a graph, we can find the slope of the line which is the conversion factor we need for our VI.

6. Comparison of Volts and Pounds

7. Apparatus The apparatus is called a vertical beam thrust balance. It consists of a pump, metal beam, and different propellers. Some of the problems we have to worry about is tare due to gravitational force, (cont.) reflection off the side of the tank, and human error in the conversions factor. The apparatus is supposed to move with the different propellers at a constant speed. Displacement needs to be measured.

8. Picture of the Apparatus

9. Problems in the Project Reflection of the jet of water from the propeller; bouncing off the walls and back to the propeller. Measuring the displacement that will occur when the motor and propeller are turned on. Take into consideration the pitch of the propeller. Shafts had to be made so that the propellers could be interchangeable.

10. New Problems Have had trouble finding AC/DC adapters that work. There is only one in the lab that is functioning properly Set back when the apparatus got knocked over we had to replace the motor because the shaft was bent. We also had to reglue the motor on the vertical beam. The shaft was wanting to move in circles towards the end, so we had to support and stabilize it with a sort of bearing.

11. Thrust Thrust is simply force. This picture is a representation of measuring thrust from a propeller. Instead of using these equations, we’ll use the lbs from the fish scale compared to the volts on the resistor.

12. Propellers Most propellers in the marine industry are made out of aluminum, stainless steel, etc. There are all sorts of propellers in use today and each one has its own design, the most common is the elephant ear blade.

13. Budget Metal for Shafts………………………$6.24 Propellers…………………………….Donated Bilge Pump…………………………..Donated Metal for Apparatus………………….Donated Epoxy………………………………...$4.00 Total………$10.24

14. Other Materials Used Resistor Wave Modulator Other FieldPoint Components Computer Wave Tank

15. Timeline

16. Hypothesis vs. Results The group predicted the large brass propeller would perform the best. After we tested each propeller we found that the plastic propeller performed the best out of the three.

17. Conclusion Although it was the medium-sized plastic propeller that worked best, and not the large brass one as we had hypothesized, we were able to calculate some thrust. If the lab was going to be repeated, things that could be improved include: accounting for the effect that gravity had on the displacement, working more efficiently, (although you can’t predict accidents like the apparatus breaking), and having propellers that have fewer variables.