Mr Piper may be surprised to hear that it was his aeroplane. American Legend AL-3 I'm told. Instructor has posted elsewhere, gist of it being that they had lifted off when they got smacked by something, willy-willy is mentioned as a possibility, but he didn't see anything, although on the nice green airfield they have for once that's not entirely surprising. Fortunately they were in a state to evacuate PDQ and just as well because fire started immediately and was pretty fierce in short order.