Scorpion Motors calculator (SC) version 3.58 (freeware)
Download from here (post #1):
http://www.rcgroups.com/forums/showthread.php?t=736782

Scorpion catalog :
Scorpion_Calc_v358.exe presents 131 motor references (all outrunners)
History
v3.47     3 addings : HK3226-900 , -1400 , -1600 (8 dec 2011) pictures included
v3.49     1  adding : HK7050-340  (30 jan 2012) picture included
v3.50     minor bug 
v3.51     S1804,HK4525, HK4530, HK4535
v3.52     New coeff. for APC 5x5E
v3.53     SII 5525, SII 5535 and SII6530 added (10 sep 2012)
v3.54     HK 4530-450 (10 jan 2013)
v3.55     HK 2520-1360 (18 jan 2013)
v3.56     Modification of Performances (Efficiency at ESC level) (02 march 2013)
v3.57     S1805-2250 + S2503-1960
v3.58     Bug fixed (pictures button)
Install :
After downloading the zip file ..
Just unzip in any folder.

Contents :
VB6 executable  Scorpion_Calc_v357.exe 
One Scorpion.ini (modified at each pgrm use) to save the preferences and default parameters
To recover the original Scorpion.ini , please Download again from the original source
One SC_readmefirst.txt (this document)

Running :
Simply run the .exe program
remark : it is MANDATORY to keep Scorpion_Calc_v358.exe AND Scorpion.ini in the SAME FOLDER

Mandatory Microsoft Visual Basic 6 library: MSVBVM60.dll (1353 kb) version 6.00.9802
For open/save functions you need Microsoft files for Common Dialog box
Generally the following files are already on the PC
Comdlg32.ocx and Comdlg32.dll (usually in C:\\Windows\System32\ )
If not, you have to download (free) from the web (Google search for Comdlg32).

Uninstall :
There are no key in the Windows register nothing into the operating system.
Just kill manually Scorpion_Calc_v357.exe
You are free to keep or not the .txt or .mmc ASCII documents

Compatibility :
There is no warranty that the .mmc files will be compatible with future versions of the freeware

Screen resolution:
Best image with resolutions close to 1280x720 or 1366x768 pixels
With lower resolutions the Scorpion Calc main window could be trimmed and not comfortable.

Graphs :
Principal graph is showing the efficiency versus the current all at WOT (Wide Open Throttle)
Blue curve = motor efficiency without the effect of temperature rising (zero running time)
Red curve = motor efficiency with the influence of temperature rising (depends of current)
Magenta curve = Speed rpm ratio relatively to no current (virtually idle) situation

Algorithms :
The author is permanently optimizing the empirical formulas and the coefficients to try
to get results as close as possible to the last real world testings.

Anyway the performances are uncertain, particularly concerning the temperature rising.
The algorithm tries to compute the temperature at the copper wire level.
The air flow could get down this figure. It depends of the installation in the plane.

Propellers :
Don't forget the possibility to "filter" the brand, in the menu "preferences"
If you want all brands choose "All" option
Brands : Aeronaut, Align, APC, Graupner, GWS, Mejzlik and some others.

Remark concerning the propeller simulation.
The pitch and the power-static thrust coefficients are uncertain.
So the results concerning the absorbed current(absorbed power), static thrust and pitch speed are approximative.
If you have yourself some test-results, you can use "generic mode" and change the Abbott and thrust coefficients,
in order to get a good fit.
The library presents 291 propellers.

A static thrust and power prop calculator is available via the main menu 'propellers'.
There is no calculation for in-flight performances.
Generally the thrust is going down when the plane speed / air increases and also the consumed power.
As a result of this "unloading" the motor-rpm is slightly going up.

The author accepts to receive propeller samples to test and add on the freeware.

About the author
This freeware was written by Louis Fourdan, who was born in 1939.
Louis is living in Antony, south suburbs of Paris, France. Married, 3 children, 7 grand children.
He graduated with a degree in electrical engineering from Supelec (France) in 1961.
He was an international radar expert (Thomson CSF) with a broad technical spectrum,
from antenna arrays to digital signal processing (DSP) and radar projects.
Louis retired in 1997 and wrote a lot of software for hobbyists using the VB6 platform.
He is knowledgeable about brushless motors for the RC world and particularly keen about solar-powered RC cars.
Louis is the founder-moderator of "Solar-RC-Cars" Yahoo group.
French friends call him "Solar Grampa".
Another one of his hobbies includes Carambole billiards. 