Conical Lycoming Rubbers

[Chris Iriarte]

Thanks Mark. I actually had it in a local shop a couple of years ago, but wouldn't swear it was the best going-over possible. I think I might advance the indexing forward one hole ... it's currently at the (looking from the front towards the tail) 1-7 o'clock position at TDC ... I recall Brian and a Lycoming doc specifying the 11-5 o'clock, TDC from another thread.

Chris

[Gilbert Pierce]

11-5 looking from the front toward the tail, 1-7 sitting in the cockpit. When you shut down, 98% of the time that is the orientation the prop will stop at. #1 blade should be at 11 o'clock position at that point and when put your fingers on top of the blade to prop it if necessary. I think yo need to move it 90 degrees CCW when standing in front of it looking at it.

[Chris Iriarte]

Concur ... on my way to the hangar now!

Chris

11-5 looking from the front toward the tail, 1-7 sitting in the cockpit. When you shut down, 98% of the time that is the orientation the prop will stop at. #1 blade should be at 11 o'clock position at that point and when put your fingers on top of the blade to prop it if necessary. I think yo need to move it 90 degrees CCW when standing in front of it looking at it.

[pa20]

Make it look like this.....

[Jim]

Hi,

Gilbert wrote: "....I think you need to move it 90 degrees..."

I think he meant 60 or 120 degrees, can't really do a 90 on six bolts.

[Chris Iriarte]

Well, it took me two tries, but the position that finally worked was ... (drum roll, please) ... Schwaner's position ("horizontal" at TDC).

I know this hasn't worked for a few folks here, but I moved it from 1-7 o'clock to 11-5 o'clock and the vibe got worse. Pulled it off, advanced it one more position to horizontal and voilá, much smoother. Mind you, still has a 4-cylinder shake, but at least the yoke isn't throbbing anymore.

Now I just have to get used to the prop stopping completely vertical ... looks strange to me.

Chris

[andya]

which prop shop do you use?

[andya]

that's about the place mine stops 95% of the time and the blade is 9-3 at top dead center

[Chris Iriarte]

A local shop in here in NM.

Chris

which prop shop do you use?

[Homer Landreth]

Well, it took me two tries, but the position that finally worked was ... (drum roll, please) ... Schwaner's position ("horizontal" at TDC).

I know this hasn't worked for a few folks here, but I moved it from 1-7 o'clock to 11-5 o'clock and the vibe got worse. Pulled it off, advanced it one more position to horizontal and voilá, much smoother. Mind you, still has a 4-cylinder shake, but at least the yoke isn't throbbing anymore.

Now I just have to get used to the prop stopping completely vertical ... looks strange to me.

Chris

"Advanced it from 11-5 one more position to horizontal" . . . . "I just have to get used to the prop stopping completely vertical" I think you meant say Vertical in both wordings. Anyway, I think you need your prop to go to the prop shop for tracking and balancing. You seem to not be achieving success in stopping vibration. Also, stopping the prop completely vertical will impede the momentum of the first cylinder firing and taking the prop "over the top" to a position where you are using the inertia of the prop swinging down to bring the next cylinder up on it's compression stroke.