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The Basic Aerodynamics of Flight

For those learning about the principles of aerodynamics, this article seeks to cover some of the basics. Like how does a propeller work on a plane, and what are the four forces of flight.

Aircraft are complex machines. Each part must work together not only to propel it forward but also to overcome gravity for it to fly. The four forces of flight include thrust, weight, lift, and drag.

If you are concerned that there is an issue with your propeller and want to have a propeller overhaul to optimize the aerodynamics, contact Stockton Propeller. Stockton Propeller is a full-service propeller overhaul and maintenance facility with the needed equipment and expertise to perform your needed maintenance and repairs.

Thrust

One crucial component of an airplane’s aerodynamics is the force of thrust. The propulsive force created by the propeller or rotor works to counteract the effects of two of the other four forces of flight — weight and drag.

Airplane wing and tail flying though a cloudy sky

Your airplane’s propeller generates thrust by utilizing the principle of Newton’s Third Law. Newton’s Third Law states that for every action, there will be an equal and opposite reaction. A propeller or jet engine pushing air to the rear will have the effect of moving the plane forward unless some other force halts it. 

The plane’s propeller will push enough air past it to cause the aircraft to move in the opposite direction of this force. The propeller must work with a high level of efficiency to provide the necessary thrust for takeoff and flight.

The amount of thrust needed will change throughout the flight. As explained below, the weight of the plane’s propeller is just one component of weight to overcome.

You must also accommodate the mass of the fuel needed to power the propeller flight. As the flight continues, fuel is consumed.  As the fuel is consumed, its mass is reduced.  As mass is reduced, less thrust is needed. 

Weight

Another of the four forces of flight is weight. Weight is the force caused by gravity.

This weight includes not only the aircraft itself, but also the mass of the cargo, fuel, pilot, and any passengers. Increased weight means that the aerodynamic forces of thrust and lift must also increase.Diagram of airflow over the wings of an airplane

In propeller flight, the weight of the propeller itself must be accounted for in the mass calculations. Also, weigh or estimate the weight of all cargo, fuel, passengers, and anything else loaded onto the aircraft.

If this weight is not accurately determined, it will affect the plane’s performance.  It will also result in miscalculating the fuel volume needed for the flight, and even the plane’s ability to take off safely.

If the plane cannot generate enough lift and thrust to compensate for the weight, then some weight must be removed. To reduce the excess load, replace materials with stable, yet lighter materials, or carry fewer passengers and less cargo.

Drag

Drag is a rear-facing force caused by the disruption of airflow over the wing, fuselage and other components of the plane. The force of drag must be overcome through the forward momentum of the aircraft. To reduce drag, you may also need to alter the design of the aircraft.

Think about the comparative wind resistance of something like a paper airplane vs. a cup held concave side toward the airflow. The pointed shape of the paper airplane allows the air to flow smoothly over its surface and wings. Paper airplane flying due to aerodynamic principles

On the other hand, the cup will catch the air and not allow it to flow past. Catching or trapping the airflow will result in much more drag. The plane’s shape will allow the air to continue in the direction it was initially flowing without much interruption.

When questioning how does a propeller work on a plane, consider the concept of drag resulting from all aspects of the aircraft. Examine the surface of the plane, as well as the position and shape of the propeller. Optimize the propeller blades to create the least amount of drag possible while creating enough power to propel the plane. 

Lift 

According to NASA, lift “is the force that directly opposes the weight of an airplane and holds the airplane in the air.” Every component of the airplane works together to counteract the effect of gravity on the plane. 

Even with an efficient propeller, a plane in propeller flight would not fly if the rest of the aircraft was not designed to generate lift. 

Lift is a complex and often misunderstood principle. Lift is the force produced by the changes in air pressure above and below the aircraft components, most specifically the wings. 

For lift to take place, a fluid or gas: in this case, the air around the plane is required. In addition to a fluid or gas, you also need a solid to deflect the flow — the airplane wings, flaps, ailerons, among others. The fluid or gas must also be in motion.Diagram of flow of air over a plane flying landscape

In order to understand how does a propeller work on a plane, you need to put the fluid in motion by propelling the aircraft through it.  Planes cannot take off without being powered to generate this initial forward momentum.

The curved shape of the wing creates lift by making the air move faster across the top of the wing and lowering the air pressure.  This reduced pressure results in less force pushing down on the wing while maintaining an upward force under the wing, creating lift.

How Does a Propeller Work on a Plane to Optimize the Forces of Flight?

The propeller, coupled with the engine, is what produces enough thrust to move a plane forward. Once the plane is moving forward, the remaining four forces of flight combine to provide the necessary lift to get the aircraft in the air.

These aerodynamic forces of flight, all working optimally together, result in an efficient and safe voyage.

If your propeller is not operating as efficiently as needed to optimize thrust, contact Stockton Propeller. Stockton Propeller is a full-service propeller overhaul and maintenance facility that can assess your plane and perform any necessary maintenance.