Prop Shop ECI PIREP

[skydvrboy]

So I called around to a few shops for quotes on my eddy current inspection.  First the bad, Yingling quoted me $450 - $550 depending on what they found once the got started.  WTF, this is less than an hour job... I guess they just didn't want to do it.

And the good, I called Redline Aviation in Akron, CO.  He quoted me $150, but said they were backed up for 3 weeks.  When I told him I would by flying through the area to attend a funeral, he told me they could squeeze me in since I lived far away.  Just asked that I call and remind him the day before.  OK, that's more like it.  When I showed up Mark, the technician, got started on it right away. 

I asked if I could help in any way and he said "Sure, come on out."   I didn't do anything to help and got in the way more than anything, but he was happy to answer my questions.  He explained that I would need an overhaul soon and thoroughly explained why.  When I asked about Aeroshell #5 vs #6, he showed me what the difference looked like between the two when they leak out on the inside of my spinner.  He also made a point of showing/instructing me on how to properly put the spinner on so I wouldn't damage it or the prop.

Less than an hour later, it was time to go see Dan, the owner and settle up the bill.  He said "Since you helped, I'll only charge you an hour of labor."  That's pretty generous using the term "help" since I mostly just stood in the cold and got in the way!  I also asked him for a quote for the overhaul and was impressed with the number he gave me.  He then took the time to go through how to package and ship the prop so that it would arrive undamaged.

I know @Cody Stallings in Arkansas has a great reputation around here (if I had been going that way, I would have stopped there without hesitation), but if you find yourself in Colorado and need prop work done, Redline Aviation seemed to be a top notch outfit.

[DXB]

2 hours ago, skydvrboy said:

I asked if I could help in any way and he said "Sure, come on out."   I didn't do anything to help and got in the way more than anything, but he was happy to answer my questions.  He explained that I would need an overhaul soon and thoroughly explained why.  When I asked about Aeroshell #5 vs #6, he showed me what the difference looked like between the two when they leak out on the inside of my spinner.  

I'm curious why you'd need an overhaul soon, and also what you learned about #5 vs #6 leaking past the seals. I have a little liquifying #6 leaking out on one blade.  

[skydvrboy]

Sure, it’s well known that the #6 will leak by the seals.  Most times that can be fixed by switching back to #5. However on the inside of my spinner there was both a thin smeared oil like substance, #6, and a thicker grease buildup. Once the prop starts leaking #5, it’s time for a reseal.

That alone doesn’t mean you need an overhaul though.  The leading edge of my prop also showed white oxidation which he said work hardens as the prop flexes. That can develop a crack that can propagate.  During the overhaul, they grind off this oxidation and repaint so you have malleable metal at the surface.

At least that’s the way I understood it. Perhaps one of our more mechanically inclined members can explain it better or confirm this.

[carusoam]

Great pireps, gents...

extra caution when it comes to corrosion and props...

Aluminum alloys that are used for strength... have a tendency to fall to intergranular type corrosion...

Essentially, it is not surface corrosion that is easily cleaned off when you get around to it...

Essentially it is a corrosion that is trying to root itself deeper into the material... it will have the physical properties of a micro crack...

With all the force of a prop in rotation, and the beginnings of micro cracks... getting corrosion cleaned up as quickly as you find it makes a lot of sense...

Under the right conditions... intergranular corrosion can spread pretty deeply... in a year... (between annuals)

PP thoughts only, not a mechanic...

Best regards,

-a-

[skydvrboy]

FWIW, my prop was zero time overhauled with new blades 3/2000.  It was then IRAN'd 3/2010.  Finally, the hub was inspected and blades dressed 8/2013.  Those were 1325, 425 and 330 hours ago respectively.