My OS .15s have cracks in the case that required surgery with JB Weld. The backplate mounted needle leveraged the threaded hole in the case to the point of failure with 2 engines. A couple of FPs have the lugs sheared off and jammed up carbs. My 2 PAW .15 diesels have been flown over the past 3 summers a combined 2400 combat minutes [2 x 20 minutes for a full length match] and have never needed more than just the dirt blown out of them. The old nylon 8x6 props almost never break, either. The planes only get burn barreled after they get too funky to clean, they're almost impossible to damage badly enough from mid airs to get deep sixed. This is truly SSC combat and all the planes are is 80 mph C/L foamies converted to elevon control and wing tip fins. The PAWS turn the 6 pitch prop about 12,000 rpm, the planes look like they're doing about 40 mph.The motor mounts are aluminum rails that are held to the center rib with 1 bolt, which allows the whole works to swing to the side in a crash, like a hinge. I discovered this feature by accident after losing one of the 2 mount bolts, and noticing that the engine still stayed put during normal flight. The down side is the stench and that diesel fuel takes more effort to get and to store, otherwise it is fun for a change of pace.