Hartzell Propeller overhaul/inspection

Hi all, thought I would give everyone a heads up wrt when/if you have your constant speed prop overhauled or inspected by a propeller facility. Due to my earlier MT governor failure and engine/prop over speed, I took my prop to Hope Aero near Toronto for a visual inspection. While it was there it was also discovered that one of the prop blade seals was pinched as I was getting a small amount of grease on my RV10 windshield. Hartzell covered this under warranty.
However when Hope Aero re-assembled the front black coloured dome to the hub, it was positioned in a slightly different position. Since the front spinner plate is bolted directly to this black dome, my front spinner/plate screw holes no longer aligned.
So I was faced with a few of options. Return the prop to Hope Aero (not a good one as the prop was torqued and wire tied to the engine), buy a new front plate, or rotate the front plate 90 degrees and re-drill and fasten new #8 nut plates to the new holes. I ended up rotating 90 degrees.......
Bottom line, if you are in this same situation make sure the overhaul facility know the black dome needs to go precisely back in the same position. Kind of a poor design on Vans part IMHO. Wish I had known this before hand.
Rick
#40956
Southampton, Ont

According to the prop shop I used, it is difficult to impossible to realign the holes. They do a lot of RV props and warned me about this when I took the prop in.

This is pretty easy to fix on your existing bulkhead. I used a divider and lightly scribed two circles (circle center being the center of the bulkhead). These lines outline the top and bottom arc of the slot. I then used a rat tail file to elongate the holes keeping within the lines. I only needed a slot about 3/8" long. Cleaned them up with a half round jewelers file and deburred. I don't think it took more than twenty minutes to turn the existing holes into nicely arced slots.

The prop shop told me that certified spinner bulkheads have elongated holes for this very reason. I don't have the experience to know any different.
This worked for me.

Prop O/H

That dome gets torqued on. Its a safe bet that it will be screwed on a little farther that it was before.

Don Broussard

RV-9 Rebuild in Progress

Prop Overhaul

While on this subject, the Hartzell manual, 115N says:

(e) Two blade propellers manufactured after April
1997 (identified by a "B" suffix in the propeller
serial number) are to be overhauled at 2400 hours.
Calendar time is limited to 72 months

Just wondering what the consensus is, if there is any, on a the 72 months time limit on the RV, O-360 Hartzell Blended airfoil combo? I've heard we are not bound to these numbers, being experimental, but is it more common for RV owners to head the 72 months, or not?

I recently bought an RV-8 with a Hartzell CS. I wasn't aware of the SB's or overhaul times at the time of purchase. Mine is 8 years past due but only 650hrs TT. Is this calender time overhaul critical? I tried to get a prop shop just do the 100 hr inspection but they refused. They would only agree to do a $2600 overhaul.

acam37 said:

I recently bought an RV-8 with a Hartzell CS. I wasn't aware of the SB's or overhaul times at the time of purchase. Mine is 8 years past due but only 650hrs TT. Is this calender time overhaul critical? I tried to get a prop shop just do the 100 hr inspection but they refused. They would only agree to do a $2600 overhaul.

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in a word NO. it is really a CYA from their legal dept. if a prop is serviced properly, there is no reason to overhaul do to time. it does make the prop shops and manufactures a lot of money though. during overhaul the blades will be ground. there is only so much metal that can be taken off, so after a few overhauls the blades are scrap.

bob burns
RV-4 N82RB

n82rb said:

in a word NO. it is really a CYA from their legal dept. if a prop is serviced properly, there is no reason to overhaul do to time. it does make the prop shops and manufactures a lot of money though. during overhaul the blades will be ground. there is only so much metal that can be taken off, so after a few overhauls the blades are scrap.

bob burns
RV-4 N82RB

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What Bob said plus more.
The requirement for OH is a recommendation, read your POH for your prop.
It is not a requirement for experimental.
That said, you do have to find a shop willing to just do an inspection/reseal.
another factor is your blades have to be in good condition and the inspection of internals has to be good as well. Example, if the blades have bad nicks or the hub has corrosion then you will need more than an reseal.

I heard a story...totally unverified but makes sense. A prop was taken to the Hartzell factory shop for a reseal/OH and the blades were found un-airworthy. They would not return the blades to the owner! Lots of issues with this story but the take away is you want good sound working equipment, you / we can hope for a reseal but might not get one.
Last reseal I got was about 800.

I have heard of props going a long time without service. But props I know about or have experience with go past the 6 years but do not make 10 before leaking seals put grease on the canopy.
You mileage may vary.

I think part of the reason for the 72 month time limit is due for any concern for corrosion. If you live by the ocean or other places that can cause corrosion faster than other location, my might have more of a reason to have it checked out. People in AZ or CA have less of a concern.

My prop and hub "look" brand new. Zero leaks and zero nicks on the blades. I was thinking about selling the plane and a potential buyer brought the AD to my attention. The prop shop told me that because they were an authorized repair facility, they could not just do a 100hr inspection because of liability.

Have a Hartzell prop on my RV-9A, that I just purchased, that is subject to the requirements of the AD.

While the AD may not be "required" for an experimental aircraft, I asked the seller of the aircraft to have the inspection performed. While I may not continue to follow the 100 hr eddy current requirement, I also didn't want to dive into an aircraft purchase not knowing if I was going to be shelling out over $8k for a prop overhaul and hub replacement.

Everyone I've spoken with about the hub cracking, including a Hartzell authorized repair company, agree that the chance of cracking is highly unlikely. The cracks that they have found are coming from high horsepower aircraft doing the aerobatic/crop dusting flying. In fact, the repair facility I spoke with mention that through all of the inspections they have performed for the AD, they have found 2 that had cracks.

Finding someone to do the Eddy Current shouldn't be difficult, and it's relatively inexpensive around $200.

While I may not do the inspection while I own the aircraft, I'll probably have it completed if I ever try to sell it.

acam37 said:

My prop and hub "look" brand new. Zero leaks and zero nicks on the blades. I was thinking about selling the plane and a potential buyer brought the AD to my attention. The prop shop told me that because they were an authorized repair facility, they could not just do a 100hr inspection because of liability.

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What "AD" are you talking about here? There's an inspection/overhaul time in the manual, but suddenly the conversation switched to mention of some AD???

With the older hubs, there's a 100 hr eddy current inspection required for possible cracks in the flanges. Updating to the "B" hub is the fix for the condition.

Sounds like what acam37 was talking about with the prop shop not wanting to complete it without an overhaul.

RV7A Flyer said:

What "AD" are you talking about here? There's an inspection/overhaul time in the manual, but suddenly the conversation switched to mention of some AD???

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All I wanted to know was some information concerning the 72 month time period for overhaul and see how other RV owners handle it? I've been on the forums a few years now and look at recent posts almost daily. This subject doesn't seem to come up very often so apparently it's not a big issue. I'm not made of money so $2,600 is a big deal for me.

To address the calendar interval (and for that matter, the hours interval, as well) issue: is there any regulatory requirement to comply with *either* of those numbers, for *any* a/c not being operated commercially? Engines, magnetos, fuel pumps, hoses, etc, etc all have time limits and typically, hours limits. But even factory a/c aren't required to comply with those numbers. Is it any different with a prop?

AD's tend to be more of a gray area with experimentals, but we're talking *recommended* OH periods here, right?

Charlie

rv7charlie said:

To address the calendar interval (and for that matter, the hours interval, as well) issue: is there any regulatory requirement to comply with *either* of those numbers, for *any* a/c not being operated commercially? Engines, magnetos, fuel pumps, hoses, etc, etc all have time limits and typically, hours limits. But even factory a/c aren't required to comply with those numbers. Is it any different with a prop?

AD's tend to be more of a gray area with experimentals, but we're talking *recommended* OH periods here, right?

Charlie

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Charlie,
FWIW, based on my conversation with Harzell tech, the 72 months is recommended primarily to check for corrosion, absent of other issues, and if we live in an area or condition (hanger vs outside) that chance of corrosion is much less, it can be pushed back unless we see sign of other issues (i.e. leaking oil)

Hope this helps but I encourage you to talk to Harzell tech for a first hand advise and recommendation. Incidentally, their cost of overhaul is fairly cheaper than the local shop (Redding) that I talked to but then there is a cost of shipping.