How does a propellor create thrust to make the plane move forward?

Question

Hi,

I was just wondering how a propellor creates thrust to make it move forward?

Answer 1

The blades of a propeller are angled so they push the air backwards as the propeller rotates.  They are just like fan blades, only narrow.

Pushing the air backwards makes the plane go forward because of Newton's Third Law of Motion: for every action (air being pushed back) there is an equal and opposite reaction (plane moving forward).

http://en.wikipedia.org/wiki/Newton's_la...

Answer 2

Rapidly rotating blades develop a lift force having a component in the direction of rotation of the axis of rotation that sums to a thrust force in axial direction.

The rotating blade causes the blade to accelerate in t he axial direction so that the fluid that has passed through the propeller moves at a higher speed than that at which it approached the vessel.

In the flow through a propeller, the approaching fluid having the speed (Vf) is accelerated by the propeller to a speed (Vp) at the propeller and to an even greater speed (Vw) is the propeller wake far downstream, resulting in net thrust F.

This increase in momentum of the propelled fluid equals the propeller thrust.