Fan/Blade Design

Question 1

How do the tip and route of the blades differ?

Answer 1

Tip of the blade travels faster than the route as it is further away from the central shaft

Question 2

Which propels more air, the tip or the route of the blade - if the blade is not twisted?

Answer 2

The tip because it travels faster

Question 3

What is the angle of attack?

Answer 3

The angle between the blade and oncoming air. Greater angle of attack = more air propelled

Question 4

Why are blades twisted?

Answer 4

So that the tip and route propel the same amount of air (cancels out the differences in speed). Route has a greater angle of attack.

Question 5

Why is it important that the blades provide the same amount of thrust throughout?

Answer 5

So that each part of the blade is under the same amount of stress - reduces amount of vibration and noise