After extensive beta testing,
the Scorpion Calc software is available for download. This program has the
parameters for all of the Scorpion motors pre-loaded into it, making prop
selection a snap. With Scorpion Calc, you can experiment with different props
and input voltages to see what kind of performance you can expect. The program
currently has a database of 254 propellers ranging from a GWS 3x2 up to a
Mejzlik 32x10, so there is a wide range to choose from. For any given prop and
voltage, Scorpion Calc will give you the RPM, Pitch Speed, Current Draw,
Watts, Motor Efficiency and Estimated Motor Temperature. The fields for Rm,
Io, Kv and motor weight are user selectable, so if you have another motor you
want to simulate, just plug in the values and Scorpion Calc will do the rest.
Scorpion Calc is the work of Louis Fourdan, a French RC modeler and
programmer, that worked with Scorpion to develop this great piece of software.
The best part is that it is available for FREE by going to the
Scorpion Calc
Download Link. The latest version is v3.10.
Here is a screen shot of the Scorpion Calc program in use. In this simulation,
a Scorpion 3020-14 motor is being tested with an APC 11x7E prop, running at 14
volts to simulate a 4-cell Li-Po battery under load. In this screen shot, you
can see that Scorpion Calc predicts that the motor will turn at 9,935 RPM with
a pitch speed of 65.9 MPH. The prop will produce 71.4 ounces of thrust and
absorb 56.78 ounce inches of torque. Further down you can see that the
estimated operating temperature of the motor at this load is 117.5 degrees F,
and that the motor is operating at an efficiency of 75.5%. With this prop, the
motor will draw 41.236 amps of current, which gives an input power to the
motor of 577.3 watts, and based on the 75.5% efficiency of the motor, this
would yield 417.1 watts at the prop. Every time you change a prop, or adjust
the input voltage, Scorpion Calc with re-calculate all of the values for the
new inputs. This makes selecting the right prop for your Scorpion motor as
easy as bolting it on!
