I posted some info about my .45 supertigre in a forum asking about pros and cons on them and I just wondered what you guys thought of these happenings:
First, I caught a tree limb on the first day of flying and broke the base of the carb. I JB Welded it on and it ran ok. It would not transition from idle to full without some gurgling and required a little time. When I got it to full or anywhere along the range it ran ok until I tried successive loops or changing the speed; it would die or blubber at that time.
Anywho, I tried it all and I finally ordered a TT.46. Well here's the weird thing. I took the engine apart tonight and as I was wiping everything down I noticed a 1mm hole had been rubbed through the very top of the chamber where it is thinnest and the bolts pass just on the other side to hold down the head. Also you could see where the piston had left the imprint of the screw's threads on the inside of the chamber at the same area. It was showing on all four bolts actually but only that 1 had rubbed all the way through. Also, the sleeve was rubbed to where it was showing an area of brass about 1/2 inch wide by 1/4 inch tall, top to botom.
Did I tweak that engine out that much by one wreck? It wasn't that big of a deal and I was amazed the carb even cracked at the base. I've wrecked engines (OS) much worse than that with no problems. My questions are these: Was my crash THAT bad? Is their manufacturing junk? and from the small amount of description Ive given does this end result seem possible and has anyone else experienced the like? Thanks for any info. Andrew

Have seen several break off the carbs and a friend has one like that with JB weld, runs good. Just remember our planes go much faster and weigh more than we think. You accident was probably about like hitting the case with a hammer, think of that and you can see how damage occurs from seemingly small accidents.

It sounds like your head bolts were way too tight and pulled the threaded part of the cylinder upward and inward pushing the liner into the piston. Or somebody tightened one bolt way ahead of the other three.

Just bad luck that it was damaged that much from your crash. I've broken engines in what seemed like simple dorks, and had engines come through horendous crashes unscathed. The one thing that I've found to keep damage down is an aluminum spinner, costs about $15-$20, but one saved engine would pay for a lot of them.

Dave,

Excellent idea! Never thought of the aluminum spinner acting as a damper or shock absorber. I plan on replacing all my plastic spinners. Thanks...

You're right about that one... I have some pretty weird looking spinner in the basement... alu really helps preventing engine damage.