ElectriCalc computer software for Windows! Shows you how your motor, batteries, gearbox and prop will fly your electric airplane!

An easy to use program with Windows display on your PC. Enter the size and weight of your airplane. Pick a motor from Ecalc's database or add your own motor specs, select the number and type of battery cells, add a gearbox if you want, then a propeller. SEE instantly how well the combination will FLY! Change any value and SEE the results of the change in the performance figures. Thrust, rate of climb, current flow (will your 30 Amp motor controller be aedquate?), airspeed, efficiency, time of the motor run. Reduce the "throttle" setting to see how much power you can save. Ecalc is the answer to an electric flyer's questions. Program comes on CD Rom and works with Windows 95 or later operating systems.

Ecalc is divided into four categies. Power, Motor, Drive, and Flight. Power is the battery setup. Motor is the motor setup. Drive is the prop setup. Flight is the flight performance of the plane.

Start by writing down the flying weight of the plane and the desired performance level.
Click on the Motor Button. Select a motor that you think will work. Note the max current draw in the comments field.
Click on the Battery Button. Select a battery that will work with the motor. Select the proper cell count. Check that the voltage per cell is somewhere between 3.5 and 3.9. This will give more accurate results. Set the throttle at the bottom of this column to 100%.
Enter the flying weight in the flight column.
Now check the prop type in the Drive column.
If you need to increase the cell count on the battery, simply click on the cell count box and use the plu and minus keys to adjust the cell count. Once again, note the change in the motors amp draw. This will also change the weight for the added cell. Make sure to stay within the motors specs on cell count.
Electric setup are figured in watts per pound.

Rule of Thumb:
60-80 watts per pound is a scale power system (30-40 degree climb rate)
80-100 watts per pound is a sport power system (40 to 50 degree climb rate)
100-120 watts per pound is a pattern power system (50-60 degree climb rate)
130 watts and up per pound is a 3D power system (vertical climb rate)
This figure is in the Drive column.

The time listed in the Power column is the run time at wide open throttel. The time listed in the Flight column is cruise time.
If you need to figure stall speeds, you will need the wing area of the plane. After you imput the wing area, the stall speed will be displayed.
For a multi engine plane you will need to divide the total weight of the plane by the number of motors to be used, then calculate it as a single engine plane. The ratio will remain the same. If the plane is running a single battery, don't forget to multiply the amp draw by the number of motors.

Critical RPM's for props are as follows:
APC Slowflyer: 65,000 divided by the diameter.
APC E Props: 145,000 divided by the diameter.

Before you commit to a setup, double check your throttle setting, amp draw, prop type, and flying weight.