Hi Norm,

Thanks for the quick response. As a clarification, the "receiver battery" I mentioned was used to power the Hacker Programming Box; it was not plugged into the receiver (nor was the ESC plugged into the receiver). Only the UBEC was plugged into the receiver. There was no electrical path between the UBEC output and the receiver battery. BTW, "sparks" occurred both when the UBEC was and was not plugged into the receiver.

WIth regard to the aircraft, it's a Goldberg Eagle 63. The estimated AUW is 6 to 6.5lbs. I'm not worried about any of the system specs; I have already ran it through MotoCalc. The predicted current draw is only around 17A and power output is 70W/lb. If anything, the Hacker motor is being underutilized. The Eagle is intended as a trainer for my kids. When they "graduate", I plan on moving the system into a much sportier airplane.

John