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Below are charts illustrating static tests performed on small motors.

The bottom axis represents the motor current and the vertical axis represents the amplitude of the three parameters: thrust, efficiency, and prop RPM. For each parameter read the current and then the thrust, efficiency, and prop RPM on the vertical axis.

Only the Thrust curve has the two motors plotted, however, I believe because the current and thrust data is so similar, the remaining data would be similar too. The Efficiency data is calculated; the rest are measured. The other curves are for the BM2409 motor only.

The two motors are CD/DVD motors used in computers and cost about $10-$20. I use them on the GWS Slow Stick models.










The graph above is a comparison of the 3 blade vs. the typical 2 blade prop.
Compared are a 9x7 3blade and a 10x4.7 2 blade on a $10.00 Tower Pro CD style motor.




The props used on the above graph were the square tipped variety of GWS product line. They appeared to be very efficient until I tested the 10x4.7 GWS slow flyer prop. They were the best so far. The square tipped "DD" props are more apt to bend the delicate motor shafts.













The test setup is pictured above. The stand is a kit suplied by BP Hobbies. The Scale is sold with the stand for $35. When the motor is spinning the thrust is directed down by the pivoting stand and read on the digital scale in ounces or grams.

The prop RPM is read on the tach instrument and the battery current read with a clip-on ammeter(not shown).

The flashlight is used for nightime measurements with the tach. During daylight hours the sunlight works very well. Artifical light does not work. The sensor picks up the 60 hz power frequency and yields erroneous results in the rpm readings.

These motors are rated for 10-15 amps max current. I ran them for a few seconds at the higher currents to see where the maximum thrust occurred at "full throttle" for all motors and prop combinations.


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