To adequately test the engine in flight you will need to purchase a plane that can take sustained full throttle runs. If you've ever seen how many of the guys push their planes at a rally you would understand this
I agree .. i have my KingCat at full throttle for 1+ min at a time sometimes, especially when doing a full throttle circuit, followed by some verticals, with power on tumbles , etc ... if not at full, im making slow passes at almost idle nice and low .... A boomerang would just blow apart i think ... ( nothing against the boomerang, as they are graeat, but not built for that kind of power ) What would be the best case here would be for the actual problem to be identified on my at400, especially to know if it is a defect on the dud I have, or if it might affect others as per the engines spec/design ...
regards,
Wojtek