Title of Project
Experimentor

Researched by Jalene A.
2004-05



PURPOSE

The purpose of this experiment was to determine how an airplane propeller’s angle of pitch affected thrust.

I became interested in this idea when I found out that flying an airplane costs a lot of money and if the propeller was producing maximum thrust then flying a plane wouldn’t cost as much.

The information gained from this experiment could help pilots and the people who travel because they could get to their destination more quickly and less expensively.


HYPOTHESIS

My first hypothesis was that the 45º pitch would provide the most thrust.

My second hypothesis was that the very low pitch (5º) would provide very little thrust.

My third hypothesis was that the very high pitch (80º) would provide very little thrust also.

I based my hypothesis on an article in the World Book Encyclopedia that said, “Each section of the propeller blades meet the air at the angle that results in the most efficient generation of thrust.”


EXPERIMENT DESIGN

  • The constants in this study were:
  • The airplane model
  • How long the blades are
  • The thickness of the blades
  • The place the experiment is conducted
  • How many blades on each propeller (4 blades)
  • The material(s) used to make the blades
  • The material(s) used to make the airplane

The manipulated variable was the pitch angle of the propeller.

The responding variable was the speed of the model airplane.

To measure the responding variable I used a stopwatch to time the number of seconds the plane took to travel a fixed distance.


MATERIALS


QUANTITY ITEM DESCRIPTION
1 stopwatch
1 model airplane
75-100 legos
5 tinker toys
1 meter stick

PROCEDURES

1. Make the model airplane fuselage from Legos.
2. Make the propeller using Tinker Toys.
3. Put the wooden blades on the propeller hub.
4. Mark a line for the starting line.
5. Then measure 177.5 cm and mark a line for the finish line.
6. Using a protractor card, set all the blades at the angle that is needed for the current test: 5º, 15º, 25º, 35º, 45º, 55º, 65º, 75º, 85º
7. Put the propeller to be tested on to the model airplane.
8. Put the airplane at the starting line.
9. Turn on the airplane motor.
10. Release the airplane and at the same time have someone start the timer.
11. When the airplane gets to the finish line pause the stopwatch.
12. Record the data on the table.
13. Repeat steps 8-12, 7 more times with the same angle.
14. Then repeat steps 6-13 with the next angle.
15. Then repeat steps 6-13 with all remaining angles.
16. Average the results for each angle.


RESULTS

The original purpose of this experiment was to determine how an airplane propeller’s angle of pitch affected thrust.

The results of the experiment were that the 15º angle went faster than any other angle. The 45º angle took more amount of time, than the 15º angle, to get to the finish line. I didn’t get up to the 85º angle because at the 55º angle it took too long to reach the finish line.

See my table and graph


CONCLUSION

My first hypothesis was that the 45º pitch would provide the most thrust.

The results indicate that this hypothesis should be rejected because the 45º angle didn’t provide the most thrust, it provided very little thrust.

My second hypothesis was that the very low pitch (5º) would provide very little thrust.

The results indicate that this hypothesis should be rejected because the 5º angle provided the second most thrust.

My third hypothesis was that the very high pitch (85º) would provide very little thrust also.

The results indicate that this hypothesis should be accepted because the 85º angle did provide little thrust.

Because of the results of this experiment I wonder if a 10º angle would provide more thrust than the 5º angle, but less than the 15º angle.

If I were to conduct this project again I would do more trials than eight. I would put the airplane in the exact same spot when I started every time. I would try not to make a little push at the start so the airplane won’t go faster. I will make sure that the blades are at the right angle and that they are pushed in all the way.

RESEARCH REPORT

Airplanes
We need airplanes to help us transport people and goods. Airplanes carry things, like mail, from one place to another. If we didn’t have airplanes then it would take longer to get our mail. Airplanes also carry people from one place to another. People can get to their destination faster by riding a plane than by a car or boat. If we didn’t have planes then it would take a lot longer to get somewhere that is far away. Airplanes make our lives better.

Definition of Airplane
An airplane is, any of various vehicles that are capable of flight, are held aloft by the force of air flowing around its wings and are driven by jet engines or propellers.

Parts of an Airplane
There are many parts to an airplane. These are some of the parts to a plane: propeller, wings, ailerons, flaps, cockpit, landing gear, fuselage, horizontal stabilizer, elevator, vertical stabilizer, and rudder.

Each part of the airplane does something specific. These are the different things that the parts do. The propeller provides thrust. The wings event lift. The horizontal and vertical stabilizers are used to control the direction of the plane. The flaps are used during the take off. The ailerons are used to turn the plane and keep it level. The rudder changes the direction of the plane from side to side. The fuselage (body) holds things together. The elevators change the pitch. The motor (engine) drives the propeller. The ailerons on the wing tips are used to rotate the body.

Propeller
The propeller is one of the most important parts of an airplane. It helps provide thrust.

Blades
There are different kinds of blades on each propeller, some propellers have lots of blades and some have very few blades. There are 2, 3, 4, and sometimes more blades on a propeller. Small planes have 2-3 blades on a propeller. The larger planes have 3-6 blades on a propeller. The larger the plane the more blades it should have. The smaller the plane the fewer blades it should have.

Definition of Propeller
A propeller is, a rotary devise, usually driven by an engine or a motor, used to propel an aircraft or boat.

Parts of a Propeller
These are the parts to the propeller: tip, trailing edge, leading edge, hub, and root.

The hub connects the propeller to the airplane. The tip separates the leading edge from the trailing edge. The leading edge extends from the hub to the tip. The trailing edge extends from the tip to the hub. The root is the point at which the blades attach to the hub.

Forces of Flight
There are four forces of flight. There is lift, thrust, drag, and weight.

Lift is a force that makes the airplane go up. The wings help the airplane make lift. The wings make lift by the air going below and above the wings. There has to be more lift than drag for an airplane rise in the air.

Thrust is a force that makes the airplane move forward. The propeller makes thrust. When the engine stars to move it moves the propeller. The propeller will pull air back and it makes thrust.

Drag is a force of friction. If drag is bigger than lift it will make the airplane slow down. If lift is bigger than drag then the airplane will go faster.

Weight is like gravity. It pulls that airplane down. If there is more weight than lift then the airplane will start to go to down. If Lift is bigger than weight then the airplane will go father up.
BIBLIOGRAPHY

Adkins, Brian and Brain, Marshal. “How Airplanes Work.” November 10, 2004. <http://travle.howstuffworks.com/airplane.htm.>

Bridges, David. “Propellers.” December 7, 2004. <http://worldbookonline.com/wb/home. >

Challong, Haslam. Flight. New York: 1995. p. 32.

Macaulay, David. Way Things Work. New York: 1988. pp. 106-118

“Propeller Parts.” January 28, 2005. <http://mercurymarine.com.>

Steketee, Drew and Liden van der, Robert. “Airplane.” The World Book Encyclopedia. 1999.


“The Four Forces Of Flight.” November 3, 2004. <http://.fi.edu/flight/own2/forces.htm.>


ACKNOWLEDGEMENTS

I would like to thank the following people for helping make my project possible:
  • My mom for getting the things that I needed.
  • Mr. Newkirk for showing me what to do.
  • My dad for helping when my project wasn’t working.
  • Mrs. Helms for taking pictures and for helping me find information.
  • Mr. Olliver for giving us time in the computer lab to get our work done.

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