motors won't spin until half throttle

[quickqestion]

I built this quad about a year ago and I recently wanted to start flying again so I purchased some new propellers and went out to go tune it. I know I used to mess with the settings a lot before but I have forgotten a lot of what I changed. My problem is that the motors only start to spin at about half throttle and then will be able to hover at about 65% throttle. I tried messing around with the input channel value settings (I'm using libre pilot) but that is only affecting how much of the throttle I input will be registered. Any Ideas on how I could fix this?

 

[ElectriSean]

The first thing I would try is calibrating the ESC's to your FC. I'm not familiar with Librepilot, but I'm sure there are some tutorials on YouTube to show you how to get it done.

 

[quickqestion]

I'll try that, is there actually any way to coordinate the throttle and esc outputs though? Would I be able to fix it by manipulating the throttle curve?

 

[ElectriSean]

I'll try that, is there actually any way to coordinate the throttle and esc outputs though? Would I be able to fix it by manipulating the throttle curve?

That is essentially the job of the FC. The term throttle is actually kind of a misnomer when it comes to multirotors, thrust would be more accurate as the FC has to control the throttle signal of all 4 motors to translate all of your stick commands into motion. This is why the ESC's need to be calibrated to the FC and not the radio throttle channel. There should be a way within Librepilot to verify that the radio and receiver are sending the correct ranges to the FC, and the transmitter should be adjusted so that the FC is seeing 1000-2000 on all 4 sticks.