Prop Problems!!!!

Cyberpilot10

So I was taking some time today to clean the bugs off my 140. As I was wiping down the prop, I noticed a crack in the paint that was in a straight line from the leading edge on the face going toward the trailing edge. It’s about 2” or 2.5” long. It had a spot that was bubbled in the middle of the crack from corrosion under the paint. I took my fingernail and scraped the paint off the corrosion area. It really looks like the prop is cracked. If you look at the picture and start at the bottom of the crack and follow it up to where the bare aluminum is. It looks like that line extends into the aluminum. It could be where moisture was trapped in the paint crack and corroded the aluminum. But to me it sure looks like the prop is cracked. I took the picture with my cell phone and enlarged it. So it looks big, but it’s really about 2.5” long. I’m grounded until Monday so the mechanic can put some dye penetrant on it and then I will know weather I have a prop for my wall. Hoping for the best, preparing for the worst!!!

Jmcmanna

Ouch...how many hours are on the prop? Do you have a pic from further away so we can visualize it more?

Cyberpilot10

Jim I’m going to run out to the hangar tomorrow and remove the prop! I will get better pictures tomorrow. Looks like I’m grounded until further notice! I have seen the damage a separated prop blade can cause. I’m not going to be the guy sitting behind one when it does if I can help it!

Cyberpilot10

Here is the picture I enlarged.

Jmcmanna

Ouch . Good luck! Maybe a new prop in your near future!

Cyberpilot10

Maybe! Just goes to show that taking the time to wipe your plane down, can be very beneficial in more ways than one! It was definitely a good catch. Maybe it will turn out to be nothing, or I will have a cool prop to hang on my wall! Just looked at new prop prices!!!! Man my wife is going to KILL ME!

Cyberpilot10

Jim the prop log shows it was overhauled 225 hours ago!

Jmcmanna

This might be one of those things that you downplay to the wife.....or it’s time to open a secret checking account for the airplane

Scott Sherer

It certainly looks like a life saving catch on your part. I hope you don't need a new prop but I'm really glad you found it. Tomorrow I'm going to look really hard at my prop!

Cyberpilot10

I pulled it off and scraped some more of the paint off! I’m not convinced either way! Will know for sure Monday

Jmcmanna

Man, it’s so close to the hub....I wonder what would cause that. Hopefully it’s something that can be filed or sanded down and you’re good to go. Definitely better to be safe than sorry on this one!

Kentwkalb

I’m glad I don’t have a painted prop...

Cyberpilot10

Your right Jim, error on the side of caution for sure! Kent, painted props sukkk!!!! I wish mine was polished, but I’m not willing to put the time and effort into mine to do it...

Scott Sherer

And I just had mine painted this year, lol. Oh well!

Joe

Just looking at the pictures, that glossy paint is not propeller paint. The reason the paint is cracked and flaking off is because of the corrosion in the base metal of the propeller, under the paint, is corroding. The prop should have been Alodined (or anodized) when overhauled and painted with Polane paint. It may be fine, it may be horribly corroded? The paint needs to be removed and the propeller inspected by a prop shop.
Where are you located? I work at a prop shop (32 years). We are in in Lake Zurich, ILL and have a driver. We will pick up your prop FOC in the Chi-town, tri-state area.
I have to warn you judging by the looks of that corrosion it appears that it was **not **protected from corrosion when it was painted, regardless of when it was overhauled. That being said I cannot disposition a propeller from a picture on the web.
The FAA frowns upon polished propeller's. See page 2, paragraph 102. (1) of this document:
https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_20-37e.pdf
To be honest with you as someone who has worked on propellers for 32 years I would never, ever leave a propeller as bare metal/polished. There are some really great paints out there for propellers and it is in your best interest to use the correct paint to prevent corrosion. Hartzell, McCauley and Sensenich use Sherwin Williams Polane paint for a reason, liability. No reason to use anything else. Hartzell came out with a great looking Silver Polane that I painted my propeller with. Its not polished but it looks really nice. We do offer paint kits if we are given a little lead time to get them together. We will NOT ship them unless it is in our truck or your car. The ValueJet accident has forever changed shipping Hazmat/flammable products (for good reason). Spruce sells some Tempco prop paints, but I've never tried them,
I own a Cherokee and just took my prop off and brought it to our shop and I added about 6 oz of paint to the leading edge and face of the blades (evenly). I would have done it at the hanger, but it is too cold this time of year. It was just overhauled by our shop 180 hours ago, but the leading edges and face of the blade out at the tip was getting eroded. The leading edges, on tip of the blade, and on the face face/flat side of the blade, on a fixed pitch prop really takes a real beating. Good Paint is the only way to keep erosion from becoming an issue tat leads to corrosion. If you are okay with a thin masked line on the leading edge, on the camber side of the prop blade. You can just scuff with maroon scotch brite pad, clean, use an alodine pen on any bare metal. Then all you have to do is touch up the paint on the leading edge/face as needed with a brush or mask and spray. I'll snap some pics when I'm out at RFD working on my plane tomorrow.

Scott Sherer

Wow, I just had a lesson in prop maintenance! Thanks so much, Joe.

Joe

Scott, You are more than welcome. I live to tell people about such things. Corroded propellers are dangerous!
Oh, Here it is, polishing:

I added a strip of black Polane paint on he camber side of the leading edge to make it much easier for touch up:

Close up of the tip camber side Notice the black paint along the leading edge):

Joe

Can't add another pic....
Tired...

Scott Sherer

Okay Joe, thanks.

Cyberpilot10

Well today the prop was inspected, the area was cleared of the paint and dye penetrant was used. There was no crack in the blade. The paint was cracked due to corrosion, the area was prepared and treated with alodine, and touched up. Thank the Good LORD. So my wife didn’t have to return my Christmas gifts to buy me a new prop for Christmas....... prop was reinstalled and aircraft was returned to service. I put about an hour on it today and will be doing my Solo X-Country in the morning...... thanks for the info Joe! I like the way you brought the black around the leading edge. I can definitely see how that would make touch ups much easier.

Cyberpilot10

Joe do they make a plastic or Vinyl strip that can be applied to the leading edge to protect it from the beating that it takes???

Joe

Really glad to hear your prop is okay.
Yes, Prop Guard: Its just 3M polyurethane tape. It works. I've never installed it. Make sure you follow directions. Scuff, clean, adhesion promoter, and application of the polyurethane tape.
https://www.mcfarlaneaviation.com/products/category/prop-guard-anti-abrasion-boot/

We install polyurethane film on all of the airliner blade heaters, but the Feet Per Minute speed (FPM) out at the tip of a blade is much greater then the FPM speed up near the hub of a heater. We see GA props with that Propguard stuff on the leading edges... Seems to work. Anything you can do to keep the paint from eroding. Or just repaint. Its in your best interest to maintain the paint. One thing that Sensenich recommends is wiping the blade with an oily rag. I do this all the time, every post flight inspection.. If you use auto wax it can have silicone in it and the next time you go to paint the prop the paint may not stick due to the silicones in the wax. Thin film of oil on the blades keeps the corrosive bug juice off and is easily cleaned with normal solvents when paint touch-up is needed.
Great to hear that was not a cracked prop.
Have a great Christmas!

Kentwkalb

Thanks Joe. I will begin the “oily rag” post flight ritual.

Scott Sherer

Looks like we all learned a boat-load of information here. Thanks Joe, your contribution of knowledge is very much appreciated by all of us! Happy holidays to you and everyone!

Joe

You are all very welcome. Happy to help. I'm a pretty busy guy, but perhaps we could have a prop shop tour at some point when the earth is warm. We are in Lake Zurich, ILL.
Scott, if you like, come spring remind me and we'll get a sign up sheet and get group tour.

Jmcmanna

I'm in for the tour!

Scott Sherer

Thanks Joe! Will do!

jimcurns

Wow, this was really good info. Thanks everyone. I might be up for a tour if the timing works. Anything prior to April 14 is best for me.

Jim

Scott Sherer

Joe: Does February 4th constitute Spring yet? We all want to come for the tour! Can you handle 10,000 members, lol?

Joe

On the 3rd I had about 3" of water at the door of my hanger at RFD. It was close to spring, Then, Alas, Winter came back with a vengeance. I can tell you Feb 8th at 8am air temp 4°F wind chill -20°F while I was pumping gas on my way to work... Balmy 10° on the way home
I'm game for a largish tour as long as we have chaperones!

Scott Sherer

Hi Joe,
I'm hoping to get in my hangar this week. There's nothing in front of it but the rubber seals are frozen down to the concrete. Hopefully it will thaw this coming week.