

Jun 18, 2011, 05:30 PM  
Toronto Canada
Joined Dec 2002
5,542 Posts


Jun 18, 2011, 06:05 PM  

Of course!
My setting is far from perfect, it can be improved... any remark is helpful! ImagesView all Images in thread

Jun 18, 2011, 07:52 PM  
Toronto Canada
Joined Dec 2002
5,542 Posts

The Thrust(Ct) and Power(Cp) coefficients are dimensionless coefficients which allow you to determine propeller thrust and absorbed power if you know the RPM, Pitch and Diameter and the air density (rho).
The coefficients in the TR237 Technical Report are determined using Imperial units (Pounds Thrust  Horsepower). http://hdl.handle.net/2060/19930091305 From the Advance graphs, the Thrust and Power may be determined for any airspeed. On the Advance Curves, the Xaxis may be considered airspeed. The Yaxis gives the value of the coefficients for that airspeed. On the Xaxis the Pitch Speed (RPM X Pitch) is equal to an Advance equal to the Pitch/Diameter ratio. A prop with a P/D ratio of 0.8 has a Pitch Speed (RPM X Pitch) with an Advance of 0.8. The Zero Thrust Speed is equal to the Pitch Speed Advance + 0.2. For a prop with a P/D ratio of 0.8, the Zero Thrust Speed occurs at an Advance of 1.0. 
Jun 18, 2011, 07:55 PM  

This explain Cp, Ct and V/nD... :
http://www.mhaerotools.de/airfoils/index.htm Things are not so easy unfortunately, Cp and Ct increase with rpm. This numbers are useful to predict prop's behavior. 
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