WLtoys F949 stock motor's lifetime is about 10 hours.
For my case, it was about 3 months , 20 times of flying. Motor become old and weak, It can't fly anymore.
I wanted longer lifetime of my first RC plane, and found upgrade to brushless motor is the best way.
With many failures, I finally made it.
For Brushless motor wiring, I read CapnBry's post on RCgroups (https://www.rcgroups.com/forums/showthread.php?2244563-WLtoys-F949/page56) and followed it.
F949 stock receiver's 3ch port is for brushed motor. (2 pin)
Electric experts might know how to use it, but I don't know how to convert its signal to brushless properly :(
So I used 4ch port (3pin , PWM) of f949 stock receiver, as a main throttle channel, and changed transmitter's left stick direction.
And after I upgraded to brushless motor, the plane become faster and heavier , so front landing gear should be more strong.
I customized with ball pen refiller as main post , it was strong and light.
Motor : 1104 8700kv brushless motor
ESC : XP-7A ESC
Total weight : 58g -> 67g
Minimum cost : about $40
Brushless motor need more electric power, 3.7V 500mah stock battery is not enough to fly long time. Flight time become short. (20min -> 7min)
But with 2 batteries wiring parallelly, flight time is almost 14minutes. I think it's ok.