Airplane Propellers – How is Thrust Produced in a Non-Jet Plane?


Home / Airplane Propellers – How is Thrust Produced in a Non-Jet Plane?

A C-130 Super Hercules with scimitar propellers providing thrust for take-off. Photo Credit: Greg Bishop

As opposed to jet airplanes, which are propelled via jet engines, many aircraft make use of propellers, which slice through the air to create thrust.  Within an air mass, airplane propellers move in a motion that is similar to that of a corkscrew – what is called a helical motion.

Aircraft such as the ATR 72, Tupolev Tu-95, and Bombardier Dash 8 use a system that incorporates propellers powered by engines that are equipped with turbochargers (i.e exhaust gas-driven superchargers), and are hence often referred to as “turboprops.” Other aircraft, such as the common single-engine Cessna – 172 use a simple propeller assembly. In this case, the airplane propeller is mounted onto a crankshaft connected to the engine.

Function of Airplane Propellers

Coordinated balance between the four forces acting on an airplane; lift, weight, thrust and drag, enable an aircraft to fly. Propellers are primarily concerned with the force of thrust – engines deliver their energy output through airplane propellers.

Propellers of a C 130J Super Hercules. Photo Credit: Greg Bishop

The internal combustion process in the piston engine of aircraft generates power and develops force. In simpler words, the airplane engine provides the propeller with power; the propeller uses this power to create thrust.

How do Airplane Propellers Work?

To generate thrust, airplane propellers must rotate. Power delivered from the engine helps in achieving this rotation. The engine, a crankshaft, and the propeller, make up the whole thrust-generating assembly. These three work in precise coordination to create thrust as follows.

  1. The airplane engine uses the fuel energy to create mechanical motion of the pistons, moving up and down repeatedly.
  2. This mechanical input impacts the engine crankshaft, as a result of which the crankshaft rotates.
  3. Connected to the engine crankshaft is the airplane propeller (directly, in most general aviation aircraft). This rotational energy of the crankshaft is then transferred to the propeller and the propeller begins to rotate.

Leave a Comment