New quad flys fine with 3S 4000mah Lipo, but wobbles with 4S 5000mah lipo?

[Joseph Cooper]

Not sure on the reason here, my F450 flys perfectly fine with a 3S lipo, but when I change to a 4S, it gets this wobble which you can hear through the motors. Both are recommended for the quad. What could be the cause of this?

Thanks

 

[tstrike]

prop size, try moving down to a smaller prop.

 

[Joseph Cooper]

Thanks, Just read that I should be using 8" props for 4S and 9 or 10" for 3S. I'll try that.