[STEVE]

STEVE on October 25, 2021 at 8:20 am #21014

Hi Nate;
The rule of thumb is that the prop should be installed so that the impulse coupling on the magneto clicks when the prop is pulled counter clockwise from what I can describe as the 10 o’clock position to the 7 o’clock position.
We’re still installing props in a position where the engine can be started by manually “propping” the engine.
FWIW your Lycoming engine will be hard to get as smooth as a Continental six cylinder engine. Just the facts.
0.04 IPS is good.
It’s possible that you’re feeling vibration that’s being “transmitted” through contact between the engine and the cowling. The vibration isolators (engine mounts) are designed to isolate the engine from airframe, but one place I would look at is cowling and baffle seals with the cowling. You’re looking for evidence to wear or contact.
Let me know what you find,
Steve

[Nathan Mueller]

Nathan Mueller on October 24, 2021 at 4:54 pm #21011

Does anybody know where a 2-blade propeller should be indexed on a ’77 Cherokee Six 300 with respect to the timing marks on the starter ring gear? I had my plane dynamically balanced at annual this year. The report came back at 0.04 IPS – however, I still feel what seems like a significant amount of vibration in cruise (at least more vibration than an “excellent” rating per the report). Dynavibe’s tech support was extremely responsive, but so far the things they said to check (compressions, airframe vibration, the way the test was performed) appear to not be an issue.

I’m aware that the service manual calls out aligning the propeller blade with the “O” mark on the mounting hole – just want to see if anybody here has the easy answer before I have my mechanic pull the prop to confirm proper indexing.

Thanks!
-Nate