# Is thrust linearly related to propeller-pitch?

1. Dec 5, 2015

### Jarfi

Simple question, Given a constant speed, is the thrust of a propeller linearly related to it's pitch?

2. Dec 6, 2015

### rbelli1

No.

Think about the thrust at 0 and 90 degrees.

BoB

3. Dec 6, 2015

### Jarfi

What exactly is the relationship then?

4. Dec 6, 2015

### CWatters

First of all what do you mean by "constant speed"? On a plane flying at a constant speed drag and thrust are usually constant and equal to each other. If you vary the pitch and as a result you change thrust then speed will usually change.

A prop blade is essentially a wing. Thrust from a prop is roughly equivalent to lift from a wing. Perhaps take a look at graphs of lift vs angle of attack. The shape of the curve depends on the wing section. It might be reasonably linear over a narrow range of angles...

Just the first one I could google. I think it's a model aircraft wing section...

5. Dec 8, 2015

### rcgldr

If you search online for "static thrust calculator", most of them don't have an input parameter for pitch, stating that pitch (within reason) doesn't make much difference in a static situation, due to limitations of the induced flow in a static situation.

The pitch comes into play when the prop is moving forwards. As air speed increase, a greater amount of pitch can be used on aircraft with adjustable pitch.

Share this great discussion with others via Reddit, Google+, Twitter, or Facebook