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SARPLT · 02-24-2015, 05:32 PM

I decided to run it again with a freshly charged 5000 mah 35C battery (6S) to confirm the numbers and I got a similar thrust at 1.58kg, voltage drop was from 25.2 down to 21.92, current was higher at 81 amps and 1812 watts. The motor was getting warm this time. As the Turnigy motor is only rated for 62 amps and 1500 watts this is pushing it well above its recommended limits. I also calibrated the throttle travel on the ESC with no change to the numbers. The stock fan unit has seven blades.

For fun I decided to compare these results with that of another EDF unit that I have setup for another model (HET 5 blade fan with a Typhoon 1680kv). Although this setup is for 8S I ran it using the same battery (6S) and Turnigy 100 amp ESC as above. Surprisingly I got more thrust 1.84kg with less amps, 57 amps. The voltage drop was also less at 22.74, understandable due to the reduced current draw. Wattage was 1335. I had expected all these numbers to be less then the first fan due to a lower kv motor and lower blade count of the fan but I am not quite sure why more thrust was produced. Could this be because of a better quality fan/motor.

I may have to do some further testing and consider other options as my original plan of using the stock fan is no longer viable. Possibly use the HET/Typhoon setup or maybe a CS fan/ 6S motor combination. I will check to see if I can fit one into the mount without too much carving.

Cheers
Marty

02-24-2015, 05:32 PM	#3
SARPLT RCC Senior Contributor I am: MartyZ Join Date: Jan 2013 Location: Brighton ON Radio of choice: Spectrum # of RCs: 8 Feedback: 10 / 100% Posts: 561 Total Props: 1	Re: FlyFly MB 339 Build I decided to run it again with a freshly charged 5000 mah 35C battery (6S) to confirm the numbers and I got a similar thrust at 1.58kg, voltage drop was from 25.2 down to 21.92, current was higher at 81 amps and 1812 watts. The motor was getting warm this time. As the Turnigy motor is only rated for 62 amps and 1500 watts this is pushing it well above its recommended limits. I also calibrated the throttle travel on the ESC with no change to the numbers. The stock fan unit has seven blades. For fun I decided to compare these results with that of another EDF unit that I have setup for another model (HET 5 blade fan with a Typhoon 1680kv). Although this setup is for 8S I ran it using the same battery (6S) and Turnigy 100 amp ESC as above. Surprisingly I got more thrust 1.84kg with less amps, 57 amps. The voltage drop was also less at 22.74, understandable due to the reduced current draw. Wattage was 1335. I had expected all these numbers to be less then the first fan due to a lower kv motor and lower blade count of the fan but I am not quite sure why more thrust was produced. Could this be because of a better quality fan/motor. I may have to do some further testing and consider other options as my original plan of using the stock fan is no longer viable. Possibly use the HET/Typhoon setup or maybe a CS fan/ 6S motor combination. I will check to see if I can fit one into the mount without too much carving. Cheers Marty Last edited by SARPLT; 02-24-2015 at 05:37 PM.