Prop Slinging Grease

[Kristin Winter]

I just got back from a run to Minnesota in Maggie, to find grease all over the left nose bowl and back as far as the stabilator. I pulled the spinner and see that it is getting flung on two spots on the spinner, each just forward of the trailing edge of the blades. From there, it works out through the aft edge of the spinner. There is nearly no grease from the blades. It is not clear whether the grease is coming from, just where it ends up on the spinner and then where it exits the spinner. Has anyone seen this before and have a clue as to what is up?

[Zach Grant L1011jock]

Kris,
Ive seen this a couple of times. Both times were shortly after servicing the prop with grease. Both times were when the engine was run at high RPM for extended periods at high altitudes (once was last year coming out to Sacto). What I think happens is a trapped pocket of air in the grease is displaced, and when it lets go, it hammers the grease out against the shank seal causing the unseat. I have been lucky in that both times, the seal reseated and all is well after cleaning up the mess.
-Zach

[Kristin Winter]

Zack,

In your experience, was it obvious where the grease was coming from? What has me mystified is that there is no appreciable grease on the back of the blades. There is just these two puddles of grease inside the spinner, which then works its way out past the backplate.

I suspect that it is significant that this is the first time that I have run the aircraft out of a high and hot place and run the props at 2700 all the way up to 12,500.

It is probably worth a try cleaning it up, regreasing, and test flying.

[Zach Grant L1011jock]

Kris,
I guess I have to say I never really tried to figure out exactly where the grease was coming from. I knew it was coming from the prop, and pulling the spinners for cleaning was necessary, at which point I lost the reference points. I cleaned it up, and then went flying again to see if it was still doing it. On both ocasions it seemed to be a pretty short lived event, ie the grease didn't look "active" on landing. On both ocasions, there was some grease on the blades, but there was lots of grease elsewhere too. On a related note, I had a crank seal that was leaking that had me pulling the prop two or three times before I actually figured out that the prop wasn't the culprit. The reverse flow from the stock Twinco cowls can be a real fooler.

Both of my grease throwing events were on quick turn fuel stops at hot and high airports, followed by max cont. power climbs and 2600 rpm continuous operations at mid/high teen altitudes. I would suggest not regreasing. Clean and fly. If you had an air bubble, its gone now so it shouldn't hammer again. If the grease leak is done, then maybe one or two pumps might be worth it, and then again, it might not. Like oil, a thimble full can look like a major spill.

-Zach

PS- Just got back from MN myself...GPZ

[Kristin Winter]

Zach,

I am not sure whether it is still spitting grease or not. However, enough of it was thrown out to coat the last couple of feet of the stabilator on that side. I am guessing that as much as a quarter cup of grease left the prop. I wonder if it would be safe to fly without regreasing.

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[Piper17P]

[Kristin Winter]