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Prop clocking indexing position

J

johnmcdonnell

Member
I read in most places that the prop should stop in the 4 and 10 o?clock position.

After our prop was re-installed after fixing a seal leak, by an A&P mechanic, it now stops at 2 and 8 o?clock.
Plane runs and flys fine with no unusual vibration.

Questions:
Does it really matter where the prop stops, or is it just convention?
If it does matter? Why?

The plane goes in for condition inspection next week.
Heeding the principle of ?If it ain?t broke, don?t fix it? should I have the prop re-clocked?

Information:
RV 4 with a fixed pitch metal Sensenich on a Lycoming O 360
I am not the original builder.

Your input greatly appreciated.
 
johnmcdonnell said:
I read in most places that the prop should stop in the 4 and 10 o?clock position.

After our prop was re-installed after fixing a seal leak, by an A&P mechanic, it now stops at 2 and 8 o?clock.
Plane runs and flys fine with no unusual vibration.

Questions:
Does it really matter where the prop stops, or is it just convention?
If it does matter? Why?

The plane goes in for condition inspection next week.
Heeding the principle of ?If it ain?t broke, don?t fix it? should I have the prop re-clocked?

Information:
RV 4 with a fixed pitch metal Sensenich on a Lycoming O 360
I am not the original builder.

Your input greatly appreciated.
Click to expand...

10-4 was recommended if you intend to hand prop (brave with an O-360.) Otherwise with a FP prop it doesn't really matter. When I installed EI last year, I changed from 10-4 to 8-2. It didn't seem to matter, although this year I changed back to 10-4. There is some theory out there that clocking can affect vibration, with 10-4 not necessarily the best orientation. Should be an interesting refresh of the discussion.
 
As said before, 10/4 clocking is primarily for hand propping. I've changed F/P clocking to different positions on my RV and saw no change.

Worked on a Cherokee with O-360 where minimum vibrations was with 12/6 clocking.
 
Mel said:
As said before, 10/4 clocking is primarily for hand propping. I've changed F/P clocking to different positions on my RV and saw no change.

Worked on a Cherokee with O-360 where minimum vibrations was with 12/6 clocking.
Click to expand...

Piper sets the location of the prop. Example... 160 hp warriors 12/6. 150 hp warriors 10/4.
 
gasman said:
Piper sets the location of the prop. Example... 160 hp warriors 12/6. 150 hp warriors 10/4.
Click to expand...

?.I read once the 12/6 was to discourage hand propping lawsuits, Not sure I
believe that!:rolleyes: More likely an effort to sell more propellers in engine out
landings? Thanks, Allan..:D
 
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