SILVER

The Blades of a Propeller

How the amount of propeller blades make a difference in the efficiency of a boat.
Shloimele Matusof
Grade 6

Hypothesis

I think that the more blades on a propeller, the better performance of the boat. I think so because, each propeller gives thrust to the boat, so the more propellers, the more speed, and stability.

Research

A propeller works by producing thrust against the water and therefore gives a forward motion to the boat. The more thrust against the water, the more power to the boat. A boat propeller consists of blades. Each blade is designed with a sight curve and a particular shape, which helps move the water down and past it. The leading edge is the part of the propeller blade that hits the water first. The trailing edge is the part where the water leaves the blade. The curve of the blade usually begins at the trailing edge and extends all the way to the hub. The curve is also known as the cup. It's what gives the propeller blade its pitch, or angle.                                                                                               

Variables

Controlled Variable: The dimensions of the blades, the boat, and the hub of the propeller

Manipulated Variable: The number of blades on each propeller

Responding Variable: Performance of the boat (speed and stability)

Procedure

Preparation for Experiment

  1. Design the boat and propellers on tinkercad.com.
  2. Download them and process them through Flashprint.
  3. 3D Print the propellers and boat.
  4. Solder the wires to the motor.
  5. Connect them with a rubber band to the 2 batteries
  6. Fill up a bathtub with water

 Experiment

Observations

Senses

Observation

Touch

The motor started vibrating.

The motor slightly heated up

Taste

N/A

Sound

I heard the motor running

I heard the propeller make a splashing sound

Sight

The boat moved slowly across the water

Smell

N/A

 

  • The propeller moved more slowly in the water than in the air
  • When i tested the propeller with 8 blades it took more energy than the other ones.

Analysis

Senses

Observation

Touch

The motor started vibrating.

The motor slightly heated up

Taste

N/A

Sound

I heard the motor running

I heard the propeller make a splashing sound

Sight

The boat moved slowly across the water

Smell

N/A

Conclusion

In conclusion, we can see that as the blades on the propeller increased, the speed of the propeller increased too. These results coincide with my hypothesis since i said in my hypothesis that the more blades the more speed of the boat.

Application

This could be useful for travel and leisure, so boats can travel at the right speed. It can also be useful for shipping cargo overseas. Depending on the amount of propellers we can determine what would be the fastest method to transport the cargo. This can be be useful, especially in situations where the cargo must be transported as soon as possible.

Sources Of Error

One thing that happened were that the propeller’s hub were too loose. To solve this problem, I added some glue gun onto the motor to make it fit tighter. In the beginning i used triple a batteries but it didn't work as well so i switched to double a batteries.

Citations

Deep Blue Yacht Supply. ( December 31, 2020) Boat Propeller. Theory and Propulsion. Retrieved from https://www.deepblueyachtsupply.com/boat-propeller-theory#:~:text=Propeller%20blades%20displace%20water%2C%20to,required%20to%20turn%20the%20blades.&text=The%20propeller%20works%20by%20turning,the%20engine%20into%20an%20action.

Acknowledgement

I would like to thank Mr. Habot for assisting me in putting together and the format of my presentation.

I would like to thank Shmuel and Yosef Kostousov for assisting me in using the 3D printer and providing me with some supplies needed for my project.