A rotating propeller imparts rearwards motion to a
- small mass of air at high velocity.
- large mass of air at low velocity.
- small mass of air at low velocity.
Explanation
A propeller produces thrust by accelerating a large mass of air rearward by a relatively small amount, giving low velocity change. Moving a large mass at low velocity is more efficient at low aircraft speeds than giving a small mass a high velocity, which is the jet approach rather than the propeller approach.
Jordi asking:
i dont understand
Community Comments (2)
S
Sete1992 Posts: 2 25.05.2022 / 03:39
It helps if you understand Bernoulli's theory which states that when a fluid enters a constriction or a Narrow passage - Pressure and Volume decreases while Velocity Increases. Like putting pressure on a hose pipe when watering your garden;the water comes out faster with less volume on the constriction but after the narrow passage the volume and pressure increases while the Speed/Velocity Decreases. Think of the turning Prop as that Narrow passage where Air Velocity is High but low pressure and Low Volume. As the Air moves further Rearwards the Velocity Decreases and the Volume Increases with Pressure. Therefore, Large Mass of Air at Low Velocity.
J
Jordi Posts: 198 09.06.2022 / 17:26
thank you very much my friend.
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