Hot battery, motor, and ESC... what do I need to do?

Gryf

Active member
I should know the answer to this one, since I’ve been building and flying for several years now, but... my FT 3D gets really hot every time I fly it. It has a new 30 Amp ESC, a Funfighter 2825-1950KV motor, and an 8x3.6 prop. So... do I need more prop? Less?

Thanks in advance!

Gryf
 

Ketchup

4s mini mustang
Did you make the slot in the top of the fuselage. I forgot what it’s called but it’s supposed to draw air inside for cooling.
 

Keno

Well-known member
What is the "C" rating of your battery? (no answer required) If it low like in the twenties it might not be able to support the power demands of your motor as the FT 3D is meant to be flown pretty hard. Thus heated battery. You can also check into the prop size recommendations for you motor by typing in 2825 - 1950KV brushless motor on the computer search engine you should be able to get the answer to your question.
 

Bricks

Master member
First off to fly the FT 3D you want a low KV motor 1,000-1200 kv with a bigger prop if you are flying it 3D as you need the air movement from the bigger prop to wash over the control surfaces so they are effective at high alpha speeds.

You really need a Watt meter to determine what you need for a prop. I have a 2212 1450 kv motor 9x45 prop running 3S it pulls 38 amps at 198 watts 4S it pulls 49 amps ( never checked watts as way to many amps ). I drop to a 7X45 prop on 4S I am pulling 18 amps at 316 watts I would not know this with out a watt meter Would be very easy to burn up the motor or ESC with out this information..
 

Gryf

Active member
Did you make the slot in the top of the fuselage. I forgot what it’s called but it’s supposed to draw air inside for cooling.
Hi! Yes, all the cooling apertures are as per the plans, and both the battery and ESC are exposed to full air flow under the power pod anyway.

Gryf
 

Gryf

Active member
Thanks for all the advice. I got to digging around my workbench and found another (larger) motor and prop. I think I’ll give that a try and see what happens. Yeah, it might make things worse, but it’s fun to experiment around. ;-)

Gryf
 

Ketchup

4s mini mustang
Thanks for all the advice. I got to digging around my workbench and found another (larger) motor and prop. I think I’ll give that a try and see what happens. Yeah, it might make things worse, but it’s fun to experiment around. ;-)

Gryf
A larger motor and prop might give you more power, but the esc and battery will get hotter and might even catch on fire.
 

Merv

Site Moderator
Staff member
So warm is OK, but if you cannot hold it for 10 seconds or so, that is too hot.
If it getting too hot. you need a smaller prop or a larger motor and possibly a larger motor.

On my FT3D, I use a Turnigy 3537 or Turnigy 3730, a 50 amp ESC & a 12x3.8 slow fly prop. This will hover at 50% throttle and has unlimited vertical on a 2,200 3S. Both motors work equally well, I get the one that happens to be in stock. The shaft on the 3730 needs to be turned around. Grind a new snap ring groove and flat with a on the shaft and reinstall.
 

Bricks

Master member
So warm is OK, but if you cannot hold it for 10 seconds or so, that is too hot.
If it getting too hot. you need a smaller prop or a larger motor and possibly a larger motor.

On my FT3D, I use a Turnigy 3537 or Turnigy 3730, a 50 amp ESC & a 12x3.8 slow fly prop. This will hover at 50% throttle and has unlimited vertical on a 2,200 3S. Both motors work equally well, I get the one that happens to be in stock. The shaft on the 3730 needs to be turned around. Grind a new snap ring groove and flat with a on the shaft and reinstall.

I think recommending a 2800 size motor for the Ege is to small just not enough power to really 2D at least to me.