MTV prop clocking

sailvi767 · #1 10-16-2019, 02:56 AM

I posted a while back about a vibration issues I have with a I0540 C4B5 and MTV-9 prop. Everything has been throughly inspected and the prop statically and dynamically balanced. The prop is very smooth at 2700 RPM but vibration increases as prop RPM is reduced. Reading several threads on here and other forums it matches symptoms many have fixed with a change in clocking on the prop. Most of the references I have found deal with 2 blade props. Does anyone have experience with reclocking 3 blade and specifically the MTV prop?
George

paul330 · #2 10-16-2019, 03:51 AM

Sorry to hear that - I have a MTV 12 which is super-smooth .....

IIRC, the boss has 6 lugs, 2 of which are more/less recessed. I think you therefore have the opportunity to rotate the prop through 180 and see if that helps the balance.

Incidentally, why did you go for the -9 rather than the more normal -12?

rocketman1988 · #3 10-16-2019, 07:32 AM

Probably because the MTV 12 is rated for a maximum of 300 HP and the MTV 9 is rated for 450 HP. For those of us who have engines producing 300+ HP, the MTV 12 would be at or beyond it's limit during every takeoff...

The guys at MT recommended the MTV 9 for safety and longevity of the prop...

sailvi767 · #4 10-16-2019, 05:10 PM

I did not know it was easy to reverse the prop 180 degrees. The prop was removed for overhaul before I purchased the aircraft. During the dynamic balance I did it was noted the existing weights on the aircraft were 180 out from where they needed to be. Perhaps they rehung the prop clocked 180 different and I should reclock it. That means another dynamic balance. Trying to wrap my head around if being 180 out from the previous mounting could account for the vibration.