Yesterday was a scheduled club fun launch day. I decided to test a new engine combination in the model that lead the Bumbling Brothers Flying Circus to a brilliant victory in last weekend's model rocket contest. Last week I used a cluster of engines on the first stage of fairly powerful engines and an upper stage of a relatively low powered engine. The idea was to get the model as high off the ground as possible before staging, where most model rocket disasters occur, with low power in the upper stage to minimize any damage it might do. This worked well, but was not as much fun to watch as it would be to stage at a lower altitude. Since last week's flight flight worked well, I thought I should try cutting the booster power in half (Engines are conveniently available in exactly one half the energy but with the same average thrust as the engines used last week.) and doubling the upper stage engine power. Unfortunately, the doubled upper stage power engine came with half the average thrust combined with a much longer burn.
At launch I was looking through the viewfinder of my camera. It was a perfect launch, even straighter than last week. As I followed the rocket up, I heard the staging with relief. Then I heard the crowd going "Oooh Nooo!" and I knew there was trouble. All six engines had fired, including the upper stage engine. Unfortunately the upper stage engine did not have enough thrust to separate from the booster, so it happily burned away, torching the inside of the booster for a little over a second. This nicely scorched the parachute and streamer backup recovery systems as well as blocking their ejection paths. In a distinct disaster, the upper stage parachute got melted just enough so it failed to open.
Despite all of this, the outside of the model had minimal damage except for the routinely broken escape tower.
And a good time was had by all.