G'day Chuck,
That's how I lost my last Katana, battery was 3 years old, but tested fine, first flight of the day, just after take off, nuthin, down she went, I will never let that happen again.
I was lucky with this one, the 1700Mah pack is under the wing tube, in the fuselage, & now so is the 1100Mah pack, perfect balance.
And no worries with RX drop outs, due to low voltage.
I'm using a DX7.
But the other one had a PCM RX, & it stopped working too, aint it funny how RX's won't work if ya don't feed em right.