# Some Help with Propellers

1. Jun 11, 2007

### Cerpin Taxt

Does anybody here knows how can i calculate (or plot) the Thrust as an airspeed function?

I guess it'd be something related with Pitch, Diameter, HP, air density...

Or... a way to calculate RPM as a pitch, diameter and power function?

thanks!

2. Jun 11, 2007

### Danger

Welcome to PF, Cerpin. I can't help with this, but others here can. Be patient and they shall appear.

Last edited: Jun 11, 2007
3. Jun 11, 2007

### Cerpin Taxt

thanks!!!

!!!

4. Jun 13, 2007

### xez

Complicated question. The simple answer is, for a
standard propepper which has been empirically analyzed,
look up the values in a table and then your equation is just
interpolation or curve fitting of the actual measured values
applicable to your particular propeller and circumstances.

For more analytical, theoretical, or mathematical models
that try to explain ab initio what effect airspeed has on
thrust of a given propeller, see the following for starters;
it's interesting to see what simplifications are made in
various models, as well as how the model results compare
with empirical data.

http://wright.nasa.gov/airplane/propth.html
http://www.aeromech.usyd.edu.au/aero/propeller/prop1.html
http://www.gylesaero.com/freeware/propcalc.shtml
http://www.jefflewis.net/aviation_theory-theo_prop_eff.html
http://www.epi-eng.com/Prop-Selection.htm [Broken]
https://www.physicsforums.com/archive/index.php/t-12827.html

Last edited by a moderator: May 2, 2017
5. Jun 13, 2007

### xez

http://www.rcuniverse.com/forum/m_608127/printable.htm
https://www.physicsforums.com/archive/index.php/t-143230.html
http://www.motocalc.com/motodown.htm

Here's another report from the NACA server that discusses relations between airspeed, thrust, rpm, and engine power:

NACA Technical Note 237
Propeller Design: A Simple System Based on Model Propeller Test Data III
Fred E. Weick
May 1927