I recently built a 250 fpv quad and I'm having a lot of trouble with it. It lifts off and flies fine for maybe 30 seconds and then starts losing power. When this happens it slowly descends, even under full throttle. I brought it home and hooked it up to cleanflight so I could see what the motors are doing. I used the transmitter to control throttle while watching the motors tab. The motors will spin up to max speed and then at least 2, sometimes 3, will immediately start losing speed until they are just barely turning. This only happens when using the transmitter. If I use the master slider in cleanflight they stay at the desired speed.

I've tried calibrating the esc's and switching to betaflight but nothing has helped. BTW, this only happens in angle and horizon mode. Acro mode they hold rpm. I'm a new pilot so I didn't try flying in acro mode yesterday but I did notice it on the bench this morning. The parts I'm using are below.

ZMR250 frame
EMax 2204 2300kv motors
Crazepony 12a esc's from amazon
Full Naze32 board with betaflight 2.7.1
Matek 5in1 v3 pdb
Frsky d4r2
Frsky Taranis X9D plus
Turnigy nanotech 1300 3s 45-90c batteries
Gemfan 5030 3 blade props

I think it may be a problem with the flight controller but I dont know for sure. What do you guys think? Thanks for reading
  

have you checked the failsafe in Betaflight, or maybe your transmitter? if everything is working fine through the motors tab, then I would check the failsafe first then if that doesn't work then swap out the FC.

One thing I would suspect is overheating ESC's.

I figured it out a couple days ago. It was in fact the failsafe. I pinched a receiver wire in between the top plate and a standoff. This was tripping the failsafe, dropping the quad since I had it set to land in cleanflight. I replaced the pinched wire and it flies great now. Thanks for the help.

(07-Jun-2016, 08:56 PM)JDunlap83 Wrote: I figured it out a couple days ago. It was in fact the failsafe. I pinched a receiver wire in between the top plate and a standoff. This was tripping the failsafe, dropping the quad since I had it set to land in cleanflight. I replaced the pinched wire and it flies great now. Thanks for the help.

glad to hear that you're back up and flying.