XJet. I noticed this today when I was observing for a guy with a Cloud Dancer 60 with a .61 GMS in it. It was running an 11x7 prop. It wasn't so much metallic but sounded like an irregular big end or main bearing soft rattle similar to what some engines make when they are bubbering rich but this happened at full throttle at normal optimum "flight setting" mixture. It was not loud enough to cause concern that there was anyhing wrong but it was something I noticed nonetheless.

In all other respects, its performance was exemplary.

It was a real "GMS Banner Day" at the field today - A guy's GMS .40 on a "Chinese Trainer" (you know the shop) with an MA 11x6 prop, pulled 12,900 rpm!! That's real grunt for a cheap .40! I helped a guy tune his GMS .47 in a .40 sized "Chinese" CAP today (best NZ$199 ARF I've ever seen) - it was running as sweet as a nut. Another guy's big stik with a .76 went really well too. The more I see of them the more impressed I am with those GMSs.