Thanks for the input. I was afraid that I might be running hot even with the finned heat sink that I’m using, that was why I wanted to bench test with the nacelles removed. It seems to be working for the couple of minutes the aircraft idles and I haven’t had a loss on landing, which is my greatest fear. Sounds like I need to replace the voltage regulator with a NiMh cell and just use the other LiPo for receiver backup.