It Prop replacement time! Oh yeah!

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Hunt-man

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Hunt-man
I have a Comanche 250, IO-540, Mccauley prop form 1957. Hub 2D36C28 / Blades 80MM-6
I knew the prop hadn't been looked at in 21 years. Was starting to have the slightest bit of play when wiggling the prop blade but no leaks. My mechanic said he'd sign it off but recommended sending it in for overhaul. Went round and round and I finally said F-it and pulled it since we were doing the annual.

Yes, the blades were less than minimum width at station 1. Yes the hub was oversized. Yes the prop was "declared" obsolete in 1982. Yes it had actually been since 1985 since it was overhauled...

I found some used blades and hub but the estimate was $6000 to piece together an old prop.
Hartzell has some good options but longer blades, 2 1/2" closer to a prop strike and mandatory counter weight change.
McCauley has a nice 3 blade kit. 1 1\2 closer to the ground. $14000
MT has a 3 blade. Same diameter. $16,800

Any experience with MT props? I've heard mixed things, delamination, long part delays...and some happy customers
I'm leaning McCauley.

At least my wife doesn't seem to care at all about the bill. So all is good.
 
I’ve recently become familiar with MT props as both a CFI and A&P. No issues. They are really nice. Don’t be surprised if it changes your max RPM. It reduced the one that I’ve been flying/maintaining from 2700 to 2500RPM max. This is a solid crankshaft 0360
 
Aside from being lighter, much more field repairable than metal props.

But... MT does suck to deal with.
 
I think I'm not going MT. Talked to three pilots that were happy with MT, one brand new prop, one that bought a plane with one and hasn't had an issue and flys only from hard surfaced fields, and another without issues.
My boss owns a DA42 and he will be waiting 6 months for a replacement MT hub, plane is obviously grounded. Another friend had one and had an inadvertent hail encounter that did no damage to the plane but the MT prop delaminated. A flight school Diamond MT prop delaminated and after trying to get parts, they gave up and bought another brand of prop. A MT prop shop said don't buy one. I fly to grass / dirt / beach strips so call me paranoid. The MT was also $2800 more. If it was a bit more rugged I'd do a MT.
 
I'm going to take one last look at Hartzell. But I'd have to change the counterweight on the crank shaft. I'm told this can be done by pulling the #6 cylinder... Has anyone done this? Should I be as scared of a counterweight change as I am.... I have a Lycoming IO-540 and it doesn't need an overhaul yet. Compressions 70+ and borescope good and clean oil.

If no counter weight change then I'll go McCauley 3 blade. But I wish there was a good composite prop or 2 blade option.
 
Is the "MV" Hartzell prop still an available option? I believe the reason the Johnston Aircraft STC requires the counterweight is because that's a C2YK prop like the ones bolted into the Arrows. Hartzell made the "MV" blade changes to the original HC-8xxxx Hartzell props ( hung on these old comanches, to act as a terminating action to AD 97-18-02). It turned them into HC-A(X)MV props, AD free. You'd be looking for HC-A2MVK-1 prop, 2 bladed, page 115 of the Hartzell application guide. No STC required, the Hartzell modification to MV shanks is retroactively applied to the TCDS.

But that's me who's about to exit this side of the hobby over recurring ADs, a minimalist who will never pay de facto service limits O/H money for a consumable like a prop. Your monkey your circus of course, just thought to throw another potential option at ya to stay in the cheaper 2-blade camp. good luck to ya!
 
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donjohnston said:
Please elaborate.
Click to expand...

Perhaps MT now has a full service facility in the USA (?), but a couple of years back if any hub repair work was needed the prop had to go back to Germany.
Any significant composite work also required the blade(s) to go back to Germany.
Finally, I don't think there's much room to file out damage on the leading edges of the blades compared to an aluminum prop - something my mechanic can do on the spot.

One example; friend of mine with a Diamond G1000 DA40 had his plane grounded for almost 6 months when his hangar partner accidentally backed his airplane into the prop. No damage to the Cessna other than the paint on the trailing edge of the elevator where it touched. The MT blade surface (not the metal leading edge) was nicked and MT insisted the blade had to be sent back to them in Germany to have the composite repaired.

The MT props are fantastic, but like many leading edge technology solutions there's often complexities/risks/costs to owning it that are different from the simple old stuff.
 
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MT has a number of service facilities in the USA. Everything from complete overhauls to repairs.

I was not talking about hub repair. I was referring to blade repair. AFAIK, there isn't much hub repair that you do in the field.

There is virtually no "filing out" damage on an MT prop. The only metal on the blade is the nickel leading edge. I'm talking about damage to the blade. Being a pusher, the Velocity props get a lot abuse. I have repaired my prop numerous times. Damage that on a metal blade would require a new blade. Grind it down, layout fiberglass, sand and paint. If you need a new leading edge, there are MT authorized service centers all around the US that can do that in a couple of days. But those nickel leading edges are HARD. Anything that would damage them to where they require replacement would have destroyed a metal blade.

Yes. MT will tell you any damage has to be repaired at one of their service facilities. Which is why I stated that MT sucks to deal with. E/AB don't have to deal with that nonsense.
 
I have a Hartzell 3 blade Top Prop and love it. Quality prop shops want about ~$2200 for IRAN to reseal, dress blades and repaint. For me the MT was very attractive but was turned off by the higher acquisition costs and challenges with repairs.
 
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