No old fart, one they weren't my engines (most important point) and in both cases they came apart in the air. One was a dual plug 120 that lost the prop, and the resultant over speed did the rest, (The owner advanced the throttle as the a/c lost airspeed) the other I forget the circumstances. The best (for me) self destruct was a McCoy 60 on steroids with a pacifer (dummy here in Oz) fuel tank in duration. It launched and at about 50ft the cylinder parted company with the crankcase, in the process the conrod destroyed what remained og the crank case. I beat the guy (first time ever) made all the sweeter because I was using a Saito 65 (on steroids) which he rubbished the hell out of