

Jun 18, 2011, 06:30 PM  
Toronto Canada
Joined Dec 2002
5,487 Posts


Jun 18, 2011, 07:05 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, 08:52 PM  
Toronto Canada
Joined Dec 2002
5,487 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, 08:55 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. 
Thread Tools  
Similar Threads  
Category  Thread  Thread Starter  Forum  Replies  Last Post 
MiniReview  Turbo Ace 915 V2 9g Motor with Pictures, Video, Flight Tests, and Thrust Tests  Tom Z  Micro Helis  96  Aug 12, 2011 08:48 PM 
Wind Tunnel Smoke  zagisrule!  Power Systems  22  Oct 19, 2008 01:54 PM  
Question  Wind Tunnel for kiteboarding tests?  DougE  Sailplane Talk  1  Jan 16, 2008 04:42 PM 
Discussion  Wind Tunnel Tests  Aphorism's Dream  Ornithopters  0  Apr 30, 2007 12:36 PM 
sources of wind tunnel pics  Tim Green  Modeling Science  0  Feb 10, 2003 08:29 PM 