Sorry I missed the youtube link the first read through, I would have seen the centerred stick and the Tx.

I know this stuff can be frustrating to work out, for us as well as the guys who designed it.

I don't want to harp on the battery stuff, but what kind of charger do you have?

Do you have a spare RX-18 to try?

Second, I'm not familiar with the DX5, are there any gear switches or mix switches? I know with my DX6i, there are certain throttle fail safes or something that act weird when switching from planes to helis. I think I have to switch off one rate and the mix.

I'm reachin' here, but I feel your pain. Good luck.