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Old 08-03-2009, 10:24 AM
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SebM
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Join Date: Dec 2006
Location: Trois-Rivieres, QC, CANADA
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Default RE: Relationship between cell and prop ?

Ok, I understand it better now. So that mean the RPM could be much higher is you increase the cell and reduce the prop. It reduce the load ( amp. draw ) but increase the RPM so better response. The things is how do you know which prop size will manage to get normal amp. draw and not too high RPM ? Testing only with a watt-meter and tach. while trying many prop. ?

Can you check my numbers please ?

I have this motor : http://www.hobbycity.com/hobbycity/s...8_900Kv_/_770W

I will be running it with a 60A ESC and a 4S 5000mah Lipo. So, I guess this motor is 0,35 ohm ? So it will give 14,8/0,35 = 42,28 A

Now I have a 12X8 folding prop in order, I hope it will be ok. The way I understand this is there is no way to tell how much amp this motor/prop combinaison will draw just from the specs, right ? Is the only way with a watt-meter ? I wanted to buy a watt-meter,what do you think of the Watts-up : http://www.hobbycity.com/hobbycity/s...idProduct=6380

If using a watt-meter is the only way to tell if the system is ok what do you do when you start up and don't have many propellers ? My problem was ordering the right prop !