Tip Stalling Bipe?
Something else to consider...
Maybe your plane DIDN'T tip stall on takeoff. A bipe has a shorter wing than a monoplane, and therefore is more susceptible to torque. Was it the left wing that dropped on takeoff? If it was, there's a good chance that you left the ground before sufficient flying speed was achieved, and the torque of the engine was to strong to be overcome by the short wingspan.