This happened a couple of weeks ago, I watched the video, should have a copy in a few days. A well respected local builder and pilot, been in the hobby a LONG timebuys a 104" P-38. Installs two G-26's, JR 10X, PCM, flys the plane for a year without incident. This year he decides to replace the battery pack with a new unit to insure he has no problems. He buys a new pack, charges it for fifteen hours and installs it. At a giant scale meet, he is now flying the plane for the first time with the new pack. During the take off roll, he feels that something is rotten in Denmark so he attempts to abort the take off. When he throttles back, the plane instead takes off on its own. Banks OVER the spectator area and proceeds to fly around for eight minutes, doing various loops and circles, totally ignoring any input from the transmitter. Plane finally drifts out about a half mile from the field, goes into a death spiral and hits a concrete pad, destroying pretty much everything. The one thing that did survive was the new battery pack. Complete with shorted cell. (6 Volt, around 2000MAH). My perception of mistakes made: 1) He installed the pack without cycling it a couple of times. 2) He didn't check it with some sort of loaded ESV before the first flight 3) He used a single pack and switch assembly on a $2500.00 plane when he should have been using some sort of battery redundancy. The only good thing to come out of this, besides the fact that no one was hurt, is that now he, and all of his friends will be paying much closer attention to their battery packs from now on. The only question I have is if he had two packs and switches, would a dead shorted cell have dragged down the second pack and insuring the same outcome?