Prop Overhaul... when do you?

[Brian Scranton]

Hey guys...I am in need of my 100 hour eddy current inspection, plus I am throwing some grease. Does anyone know anywhere in Colorado that will have a look for me? Last inspection was in Vegas while we played for a few days. I'd love to find something closer to home (KMTJ). 

[Ruth and Brian]

Hello, we are looking at a 1977 M20J that has a B2D34C212 McCauley prop that was overhauled in 2001. Now prop is 645SPOH. We would like to know if it is probably still ok or would it require an OH because of time? It was overhauled before but new blades were installed in 2001.

[Ruth and Brian]

On 9/3/2017 at 12:28 AM, Cody Stallings said:

Being Part 91 it's clear complying with Manufacturers TBO is optional.

There is no doubt the propeller is one of the most highly stressed parts on an Aircraft, however they are built like Tanks.

Very Robust.

To the actual Question now.

Propeller Overhaul.

Overhaul is a word used loosely in the aviation community.

But when you request Overhaul in a Repairstation like mine, your propeller will be put through the rigors of the Manufacturers O/H Manuel for your propeller.

There are many steps, many procedures, many measurements, many mandatory new parts.

When grinding the blades, all damage is to be removed from the blades. A lot of material has to be removed.

After all of this is complete, you will have a fresh O/H Propeller, a Large Invoice an Thinner blades.

Thats the truth of the matter, with no BS.

 

Propeller IRAN

With an IRAN(Inspect Repair As Necessary) the repairman doesn't have his hands tied.

We can remove only the material needed to do what needs to be done. Corrosion Nicks Galding ect.

Your looking for Airworthiness Issues, anything that could compromise safety of flight.

With this, the propeller will have certain parts replaced.

We look at high stress parts an Wear parts: Counter weight bolts, Ball bearings, Actuating pin bolts, ect. They are replaced with new parts, An of course new Orings an seals.

If at any point in the IRAN process something shows the need for MT, PT or ET inspection, we do it.

When complete, the propeller will look like new agin, like an Overhaul.

You will have a Smaller invoice, an thicker blades.

The Catch:

IRAN doesn't Satisfy an O/H.

So if you IRAN, it will be continued time on the previous O/H or New.

Generally speaking, most people wait for a visual cue before removing a propeller for service.

Grease Leak, Red Oil, Loose blade.

I think that weighting a little to long, However I have taken props apart that were almost 30 yrs old, that looked New on the inside.

Then I have taken them apart that weren't even to their TBO(5-6yrs) yet, that I ended up throwing in the trash.

How often it's operated, an how often it's serviced plays a big roll in this.

Hartzell an Oil Filled McCauley propellers seem to have the best life expectancy.

Hartzells can be greased, An the Oil Filled McCauley has a Quart of SAE 30 Oil in it.

Its the McCauleys that have grease in them, that have problems.

They can't be service in the field.

So after 8-10 yrs they spit a little grease out then stop.

When it stops its out of Grease, an corrosion starts.

I will attach a few pictures of a Cessna C-421 Propeller.

The stuff that looks like mud, is actually What's left of the grease.

Bearings show signs of heavy pitting on the surfaces.

 

 

 

 

[Ruth and Brian]

Just now, Ruth and Brian said:

Hello, we are looking at a 1977 M20J that has a B2D34C212 McCauley prop that was overhauled in 2001. Now prop is 645SPOH. We would like to know if it is probably still ok or would it require an OH because of time? It was overhauled before but new blades were installed in 2001.

 

1 minute ago, Ruth and Brian said:

 

 

[Cody Stallings]

It’s tough to say.

At almost 20 years it may not need an overhaul, but it could probably use a reseal. Over that duration of time with on 600hr of operation I’m sure the Orings need to be replaced. 

[larrynimmo]

1 hour ago, Ruth and Brian said:

Hello, we are looking at a 1977 M20J that has a B2D34C212 McCauley prop that was overhauled in 2001. Now prop is 645SPOH. We would like to know if it is probably still ok or would it require an OH because of time? It was overhauled before but new blades were installed in 2001.

just for what its worth...the M20J I bought 2 years ago in a 1981 model with 1545 hours....I changed the engine at 1663m and had the prop fully overhauled at that point.  It wasn't leaking and it looked great with the original 36 year old paint....(overhaul cost $2,500...rebuilder said that is "the going rate"

according to the prop log book, on two separate times, O rings were replaced due to leaks...but no overhaul or resurfacing the blades

[Ruth and Brian]

Thank you. We also saw an 83 with a gear up that has a new prop, but it’s the 3 blade McCauley scimitar. Hear negatives about that though. 

[carusoam]

The only negative you might hear about three blade props on 200hp engines...

• Blade surface area is increased, great for T/O roll, bad for top speed...  a few knots, so not terrible...
• The mismatch of even cylinders and odd blades should have some measurable vibration challenge, but can’t be noticed by the seat of the pants...

PP thoughts only, not much to add... and Welcome aboard/congrats on the first post...

Best regards,

-a-

[Hank]

5 hours ago, carusoam said:

The only negative you might hear about three blade props on 200hp engines...

• Blade surface area is increased, great for T/O roll, bad for top speed...  a few knots, so not terrible...
• The mismatch of even cylinders and odd blades should have some measurable vibration challenge, but can’t be noticed by the seat of the pants...

PP thoughts only, not much to add... and Welcome aboard/congrats on the first post...

Best regards,

-a-

The 3-blade Hartzell on my C was dynamically balanced at install back in '03. I had that checked at annual in 2017, still at .01 ips.

Great climbs, provides hugher than book cruise speeds. At my preferred travel altitudes if 7500-10,000 msl, my little C generally indicates in the mid-140s mph (often 147-148 KTAS). Not sure I believe that a 2-blade would really give 150 KTAS on 180 hp . . . .

[all4thekidz]

On ‎9‎/‎3‎/‎2017 at 2:31 PM, jetdriven said:

The problem is you won't know your blades have been ground to limits and condemned until after it's already happened and then you're out $7000 for a prop.  

This happens quite frequently I don't know percentagewise but when you called in some shops to drop your engine off to have an overhaul,  the price is pretty well known and barring the crank or the case being bad the price is the price... the problem with the prop is they opened it up and do a bunch of stuff to it and then they call you with a price and sometimes it doesn't include a prop when you're done

 For example I called my local prop shop when I had to change the engine out the prop was nine years old and had 1200 hrs. on it and they told me it must be overhauled to be airworthy. I told him the service history of it it was new when it was put on the airplane in and it never hit the ground or been seriously filed on and he said "I don't know it's very iffy send it in and will call you after we find out if the blades pass or not". Repeated questions trying to pin him down he's being very evasive and frankly I had just about zero confidence that I will see a prop at the end of this deal. So I sent it to San Antonio propeller $650 later it was painted static balance and reassembled and it's been going strong for six years now. 

 

this is the problem I had! Prop had about 900 hours but the age was around 12 years, was removed for some major work on the engine so I decided to send the prop for overhaul since it was off and its age not due to any performance issues.  I received the prop back in a BOX along with the blades claiming they were .0050 outside a limit and a replacement prop would cost $$$$$$$.  Now I have a disassembled prop and like working with your doctor I am interested in a second opinion.  Most prop shops are not interested in looking at a disassembled prop!  The wooooos of ownership!!!

TC

[LANCECASPER]

39 minutes ago, all4thekidz said:

this is the problem I had! Prop had about 900 hours but the age was around 12 years, was removed for some major work on the engine so I decided to send the prop for overhaul since it was off and its age not due to any performance issues.  I received the prop back in a BOX along with the blades claiming they were .0050 outside a limit and a replacement prop would cost $$$$$$$.  Now I have a disassembled prop and like working with your doctor I am interested in a second opinion.  Most prop shops are not interested in looking at a disassembled prop!  The wooooos of ownership!!!

TC

So none of us send ours to the same shop - which shop was that?

[N201MKTurbo]

39 minutes ago, all4thekidz said:

this is the problem I had! Prop had about 900 hours but the age was around 12 years, was removed for some major work on the engine so I decided to send the prop for overhaul since it was off and its age not due to any performance issues.  I received the prop back in a BOX along with the blades claiming they were .0050 outside a limit and a replacement prop would cost $$$$$$$.  Now I have a disassembled prop and like working with your doctor I am interested in a second opinion.  Most prop shops are not interested in looking at a disassembled prop!  The wooooos of ownership!!!

TC

Put it back together and take it to a prop shop.

[carusoam]

6 hours ago, all4thekidz said:

this is the problem I had! Prop had about 900 hours but the age was around 12 years, was removed for some major work on the engine so I decided to send the prop for overhaul since it was off and its age not due to any performance issues.  I received the prop back in a BOX along with the blades claiming they were .0050 outside a limit and a replacement prop would cost $$$$$$$.  Now I have a disassembled prop and like working with your doctor I am interested in a second opinion.  Most prop shops are not interested in looking at a disassembled prop!  The wooooos of ownership!!!

TC

Let’s invite the MS prop guy to throw in some ideas...

@Cody Stallings looking for a second opinion on a prop that has been disassembled for inspection... report was a minor out of tolerance on some part of the blade...?

Cody has always been helpful for MSers with prop questions...

Best regards,

-a-

[Cody Stallings]

Need More information.

Depends what is being done to the propeller, an what this said tolerance issue is on the blade.

[carusoam]

@all4thekidz message for you above ^^^^

Best regards,

-a-

[all4thekidz]

After recommendations I took it to another shop and they were content that the prop was good  for another overhaul and therefore I will be in business in short order.  almost 2 years working on this darn "F".  I will not give up!!!!

TC

[Hank]

@all4thekidz--howdy, neighbor!! Where do you keep your plane? I'm in annual right now, so will not pop in for a visit just yet. I'm now based at KALX on the Lake.

[all4thekidz]

Prop overhaul complete.  New tires tubes bearing repacked.  Brakes cleaned and leaks stopped. Altimeter installed. 

Next hurdle is installing bracket next to gear actuator. Then on to steering bushing.  Should be running in about 3 weeks!

I will prevail!

[carusoam]

The first 90% of success comes from positive attitude...  

-a-

[Erik]

On 9/25/2017 at 6:29 AM, Brian Scranton said:

Hey guys...I am in need of my 100 hour eddy current inspection, plus I am throwing some grease. Does anyone know anywhere in Colorado that will have a look for me? Last inspection was in Vegas while we played for a few days. I'd love to find something closer to home (KMTJ). 

Where in Vegas? I can’t find anyone here that does it. 

[MooneyMike]

On 10/18/2020 at 8:44 PM, Erik said:

Where in Vegas? I can’t find anyone here that does it. 

Golden State in San Luis Obispo. The weather is nicer here.