My Posts: All Forum Topic
I re-read a couple of your posts/replies and, I am assuming/hoping you are running with the EB kit/modification if you are running 810/800mm blades. If not, your TR and Main blades are going to become "kissin' counsins." As I understand it, the switch between the 14T and 13T pinions was brought about by the switch to the G26 engine coupled with the ability to run longer (720mm) blades. The 11T pinion came around with the EB and EB modification kit (speaking strictly Intrepid here and not the Observer or Twin) for running the 810mm blades. The 11T pinion, to me, would take you below the stock power band if you are not running the longer blades in conjunction with the EB package.
I am on a "horse of a different color," so to speak and am running the shorter, stock-length (33 inches), heavy duty EB tail boom and EB tail rotor gear box with the Hanson 3D Pro engine. This engine has a spec'ed max RPM value of 16,800, so to get into the power band, I dropped down to an 11T pinion. With the 13T, my throttle curve was almost non-existent just to keep the head speed down to a manageable level. I flew yesterday and the 11T pinion coupled with some throttle curve adjustments appears to put me smack dab in the middle of the Hanson's power band (about 13,770 RPM if my math serves me correctly). I was not able to tach it yesterday, however, by sound alone, I can tell that the 11T did the trick. Will get a tach on it once I have a partner with me.
On the vibration issue, I would be hesitant to answer your question, other than to say that if you have vibration (noticeable) at 10K RPM, you are probably going to have it at a higher RPM as well and that you probably need to go looking for the source, i.e. crank shaft run-out, loose items, etc. Since you don't mention the vibration symptoms, it could be anything from engine tuning to TR thrust bearings installed incorrectly. Although a gasser has a bit more inherent vibration, the Intrepid, properly set-up and with a well-tuned engine is an incredibly smooth machine.
"There are those who have...and, those who will" IRCHA #2117, AMA #70068, Turbine Waiver #105