Oil leak vs Grease leak MT prop ?

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Steve
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Re: Oil leak vs Grease leak MT prop ?

Post by Steve »

Rich wrote:
Sat Dec 19, 2020 3:25 pm
Steve wrote:
Fri Dec 18, 2020 12:00 am

The other unusual thing (to me) in your photos, is the gray silicone? around the base of the blades. My blade roots don't have anything like that:

IMG_4339.jpg
This gray collar between the blade ferrule and the blade itself is present on mine. It's referred to in the MT manual (6.2.2.4) and is to be kept intact. It's to keep moisture from seeping into the joint between the blade and the ferrule. Quote:

Check that silicone, sealing the blade to the blade ferrule, is not damaged. If a damage is obvious, repair that no moisture can enter into blade body and blade ferrule

Rich:

The silicone between the blade and blade ferrule (I think) refers to this:
IMG_4339.jpg
I was referring to the goopy stuff between the blade ferrule and the ring with the bolt through it (which the 180-17 blades don't have). As we both presume, that stuff doesn't look like factory stock. I will be able to comment more authoritatively on this in the near future, since I have 3 new 183-59b blades on order from the MT factory in Germany to replace my 180-17 blades (but that is another story for a future thread).

Steve
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Re: Oil leak vs Grease leak MT prop ?

Post by Rich »

In re-examining the original pictures, they mostly support my hypothesis about that mating o-ring. What appears to be an oil sheen coating the right upper cowl and right side of the canopy.

However the picture of the right cooling intake area does not. That looks like the historical grease slinging pattern and is out front of the cowling seams. But grease sling dots should be all over the plane, not just this one small area. Note that the left side of the cowling has nothing of note on it. Another characteristic of severe grease-slinging is it produced these little black dots even back on the vertical stabilizer.
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Re: Oil leak vs Grease leak MT prop ?

Post by Davestation »

I didn't see all the pictures on my phone. It's almost certainly coming from the weep hole as Steve pointed out. There's an obvious trail from there across the bulkhead and rearward.

It doesn't have to be a lot, a tablespoon would probably be enough to coat the entire top cowling and windshield.

The original round tips have that giant snap ring at the blade roots, the newer models have the castle looking roots with bolts that get covered in silicone. Those little bolts don't actually get safety wired despite having a hole for one--there's nothing to safety them to. They could have made the silicone look a little prettier though.
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Re: Oil leak vs Grease leak MT prop ?

Post by yl472401 »

Well do, steve, prop will be taken off and send to a prop shop in Ohio for service.

Steve wrote:
Fri Dec 18, 2020 12:00 am
Bryan:

The first photo wins the prize. To me, it appears that the source of oil/grease spatter is the small hole at 7 O'clock on the face of the hub. The older versions of the MTV-12 hub (like mine) do not have this hole. MT added it to try to mitigate the grease spatter issue on these props. There was even a service bulletin to drill a hole in the hub of the older S/Ns to try to reduce the spatter. The fix was actually to bore out the hub, and install steel sleeves for the blades, which seemed to allow for better sealing. I had this done when my prop was overhauled about 7 years ago (hub had to be shipped to Germany for this), and it has been dry as a bone since.

The other unusual thing (to me) in your photos, is the gray silicone? around the base of the blades. My blade roots don't have anything like that:

IMG_4339.jpg

although my blades are 180-17f and I suspect you have the scimitar prop with 183-59b blades. The design of the blade root appears much different, but that sealant doesn't look like a factory job...

Your blades do look like they have a very small amount of grease leakage, but I think the majority of leakage is coming from the previously mentioned hole, and running/being blown aft. Now, as to what is causing it, I think that determination will have to be made by a prop shop. Keep us informed as to what you find.

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Re: Oil leak vs Grease leak MT prop ?

Post by yl472401 »

Pictures from today when the airplane is in the hangar. Image
Image


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Re: Oil leak vs Grease leak MT prop ?

Post by Steve »

Just to close the loop on this from one angle, I had mentioned that the blade roots on Bryan's prop were quite different than mine. I suspected that was due to the fact that I had 180-17f blades, and he had 183-59b blades. Well, my prop just came back from the overhaul shop. I upgraded to 183-59b blades, and the root looks identical to my old blades:
IMG_4476.jpg
IMG_4477.jpg
I asked the technician about the "castle nut" design blade roots, and he asserted that they were used only on MT props for the diesel engines. Something to do with the stronger power impulse in diesels. Bryan, is your prop original to your airplane?

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Re: Oil leak vs Grease leak MT prop ?

Post by yl472401 »

I think it is, I’ll look into the log book. As far as I know there was a repair done previously for prop strike.
It’s still not back yet from over-haul
I’ll post some picture once it is back.


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Re: Oil leak vs Grease leak MT prop ?

Post by Steve »

yl472401 wrote:
Sun Jan 24, 2021 2:47 am
It’s still not back yet from over-haulImage
I feel your pain. I have a good relationship with my local prop shop, and they are usually pretty fast, but mine took over 2 months this time (although 3 weeks of that was negotiating how much they would give me for my old blades, and waiting for the new blades to be shipped from Germany).
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Re: Oil leak vs Grease leak MT prop ?

Post by yl472401 »

Steve wrote:
yl472401 wrote:
Sun Jan 24, 2021 2:47 am
It’s still not back yet from over-haulImage
I feel your pain. I have a good relationship with my local prop shop, and they are usually pretty fast, but mine took over 2 months this time (although 3 weeks of that was negotiating how much they would give me for my old blades, and waiting for the new blades to be shipped from Germany).
Wow, it will take that long ?!ImageImage


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Re: Oil leak vs Grease leak MT prop ?

Post by Steve »

Well, I don't think you will need new blades, so the only parts they would need would be the hub overhaul kit, which most shops that overhaul MT props have in stock. What time estimate did they give you when you asked them to work on it?
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