Mooney M20J Propeller Inquiry

[Mehmet Kusmez]

Folks,

I've slow-rolled my airplane search for now, as I have other adventures to embark on first. I still lurk on controller.com, Trade-a-Plane, etc., and I was wondering if anyone had any wisdom on propeller type for the M20J. 

I have read that some of the three-bladed options had vibration problems, although I cannot seem to recall the source. Is this also true for the MT propeller? I would love to hear about anyone's experiences with different propeller types for the M20J. The obvious things I'm interested in are performance, noise, and vibration. I'm an engineer, so I don't mind nerdy.

Mehmet

[toto]

There are a lot of MS threads on propellers. People with MT props seem to love them, but the one minor downside is that they’re lighter .. which moves your CG aft and can be tricky to offset. 

[KSMooniac]

Moving the CG aft is a very good thing on a J, perhaps not on a short body.

The MT is the lightest and smoothest option for a J except the brand new composite Hartzell is a pound or two lighter, I believe. The MT is also a smaller diameter than all of the others, so that offers a bit more ground clearance. There are no vibration concerns or restricted RPM ranges either. With a dynamic balance and a well-balanced engine I got mine down to 0.01 IPS. I've posted extensively here for years on the topic so start looking at my old comments.

Sent from my motorola edge plus 2023 using Tapatalk

[Will.iam]

46 minutes ago, Mehmet Kusmez said:

Folks,

I've slow-rolled my airplane search for now, as I have other adventures to embark on first. I still lurk on controller.com, Trade-a-Plane, etc., and I was wondering if anyone had any wisdom on propeller type for the M20J. 

I have read that some of the three-bladed options had vibration problems, although I cannot seem to recall the source. Is this also true for the MT propeller? I would love to hear about anyone's experiences with different propeller types for the M20J. The obvious things I'm interested in are performance, noise, and vibration. I'm an engineer, so I don't mind nerdy.

Mehmet

If you really want to geek out run AI on propeller charts for optimum rpm and altitude efficiency. 

my McCauley 2 blade had a narrower 90% or better RPM with sweet spot altitude of 18k. My MT-12/188-53 propeller has a 90% over 200rpm band with sweet spot altitude of 20k. But i got mine because of the 5% increased performance for ground roll and climb out as i live on a short airfield with trees and that has paid off in spades for me. 

[Will.iam]

The composite top prop from Hartzell is not STC for my M20K or i would have to really sit down and weigh the advantage of better acceleration over cowl removal for maintenance issues. that 2 blade vs 3 blade would represent. my MT 3 blade is much more prone to scuffing the prop with the cowl when removing and installing the cowl when the blades are lower than horizontal which would not be the case with 2 blades. My top speed inefficiency of having an additional blade was offset by the 13 pounds lighter nose thus moving the CG aft in cruise. The top prop would be even more speed gain with the further aft cg lighter weight, and one less blade drag and maybe with the smitar blade design not that much loss on takeoff roll but alas with no STC for my M20K i stopped researching the top prop.