Yes, it's on the Stinger. Same day I was able to coax a full torque roll out of it it starts acting up
I kept doing them, just had to get out quicker when trouble started. Really strange. I would go vertical for 500 ft and the engine would clear out and act better - then after a long idling approach to pull into hover/TR it would get to half throttle ( enough to hover) without much problem. Then going to full when it was time to get out, it would sputter. Good thing that big wing area keeps it from falling back down too much.
Thanks for the advice - I saw what a low battery on ignition would do a couple weeks ago - just would never get to full throttle. This time 'round - it get's near full RPM - maybe slightly low- it just takes a little effort before it gets spinning full-on.