F550, hot motors

[carguy4471]

Just built up an F550 using the arf kit. All stock, naza controller, fpv receiver and battery, running 4s 5000mah. Has an x468 gimbal with gopro and using 10in props.

After a 7 minute flight I noticed the motors are very warm/hot. You can touch them but I wouldn't squeeze and hold em. Escs were not even warm, battery not warm at all.

Normal? Or should I be looking into this?

Thanks all!

Sent from my EVO using Tapatalk 2

 

[chipwich]

If you are using the stock props and a 4S pack, per page 7 of the F550 manual and in my experience, use the 8 in props. They spin at a higher RPM and your motors and ESCs won't have to work as hard. There is a side benefit of increased stability. They will be hot anyway, but not as hot.

 

[carguy4471]

Very good sir. I appreciate the input. I read the naza manual and didn't see it. I was thinking that with a load 10in would be better. I'll throw the 8in'ers back on there and go to it.

An a side note, when are the 10in props suitable??

Thanks again!!

 

[chipwich]

No problem carguy, and I still have a mountain of knowledge to climb as well. AP, FPV, MC, GPS, etc. It's a big list. The 10 in stock props are shown for 3S packs, and I assume that it's a weight thing, since they can have the same mAh and C ratings. Some folks report having good success with 10" aftermarket props, like the Graupner 10x5s. I haven't gotten around to trying those yet, but want to. You might have read that the stock props are fragile, and that is no joke. I broke quite a few early on, but realized that I was putting too much torque on the nut and even though I was using a small amount of thread lock on the metal shafts, there is a risk of contamination with the plastic. They just need to be snug and no thread lock anywhere near the props.

In genereal higher amps generate more heat and amps= watts/volts. So given that a loaded up heli should require more watts to lift, a higher voltage battery should generate less amps and heat to lift the same load. But since usually the higher voltage battery weighs more, DJI probably wants props with either less diameter or lower pitch. At least that's the theory. There's probably more to the equation (like number of rotors) and a point of diminishing returns. There is an interesting video done by the quadrocopter guys comparing a 5S and 4S setups which run contrary to the formula above. The consensus supports smaller props for higher cell count.