Prop governor

[jwx96]

Thanks for the numbers Bernie. It sounds like you made a good move. Enjoy your new prop!

[jwx96]

The Hartzell 2-blade composite prop is now $25,000. I’m sending my current prop to MT USA in Florida for a faster reseal repair for likely 10% of that cost before considering again the new prop option.

[krellis]

My 2003 DA40 with the Aluminum Hartzel PowerFlow Version prop is 1703 lb and 95.2. I've just replaced the aluminum prop with the Hartzel Composite. Awaiting the final numbers because the prop governor had to be overhauled when the new prop failed to make the required full power RPM. I am very glad I bought the new prop before Hartzell was sold.

One thing to have your shop check is the low pitch stop on the propeller. If that is not set correctly, you can get the symptoms you experienced with not getting full takeoff RPM (or surging upon application of takeoff power).

The Hartzell composite is a great prop. We had it on our second DA40 and I bought a similar version for our experimental RV-7A plus a three blade version for the RV-10. You should experience better takeoff acceleration and deceleration in the pattern and on landing. It's a great speed brake when the power is pulled to idle.

[jwx96]

I heard back from MT USA today. When they opened the prop there was zero grease inside. It was completely dry. The bearings were damaged. They found that a piece of one of the bearing races had broken off. They said they saw signs of heat damage. I'm not sure how this happened. The prop is 390 hrs SMOH in 2021. MT is going to complete the inspection and give me an estimate for cost and time to repair. I'll have to decide if it's better to do that or to replace.

[Rich]

I heard back from MT USA today. When they opened the prop there was zero grease inside. It was completely dry. The bearings were damaged. They found that a piece of one of the bearing races had broken off. They said they saw signs of heat damage. I'm not sure how this happened. The prop is 390 hrs SMOH in 2021. MT is going to complete the inspection and give me an estimate for cost and time to repair. I'll have to decide if it's better to do that or to replace.

Similar to my '09 problem. The major delay (100 days altogether) was that the blade ferrules were damaged and the blades had to be sent to Germany for repair. The ferrules are the steel bases of the blades that actually act as races for the bearings/blade interface. They had to be replaced, which requires an involved process of removing the ferrules and replacement. Temperature differential is involved for an interference fit between the wood cores and the ferrules.
It would seem the most recent overhaul was improperly done. Even if some grease leaked out there would still be some in there. In my case it was crappy grade grease allowed by MT that simply deteriorated.

[dmloftus]

I heard back from MT USA today. When they opened the prop there was zero grease inside. It was completely dry. The bearings were damaged. They found that a piece of one of the bearing races had broken off. They said they saw signs of heat damage. I'm not sure how this happened. The prop is 390 hrs SMOH in 2021. MT is going to complete the inspection and give me an estimate for cost and time to repair. I'll have to decide if it's better to do that or to replace.

Did MT do the overhaul 390 hours ago? I have been really impressed with the guys in Deland.

[jwx96]

I agree. MT USA in DeLand is great. No, the prop was overhauled locally, but they were a MT service center. I’ll post some pictures that MT sent me.

[jwx96]

The "good news" from MT is that they can repair the prop for $3500. They need 4 working days then it'll be on it's way back to Minnesota. Nothing needs to be sent to Germany. I can keep the shipping crate for $450 or ship it back for more. I plan to keep it here to have on hand. I've only flown my plane 6 hrs in the last 90 days because of the maintenance and waiting, but I changed the oil and added Camguard just before the maintenance started and it's been a dry winter so hopefully there won't be too much internal corrosion. I just ordered a DryBot dehydrator, and should have got one earlier, but at least it will be on hand for the next time I have a prolonged down time. Would anyone recommend changing the oil again after the mechanics finish and I start flying again? My annual is May 6 and I'll get an oil change then for sure. Here are some of the photos that MT sent me when they disassembled the hub.

[Steve]

That is amazing - there should be a lot more grease in there. I saw my prop disassembled for its first OH. It had 11 years and 533 hours on it. There was a lot more grease in it, even though it had the original hub sleeves and seals which were prone to spit grease. All of the balls were fine, I think that a couple of the spacers were broken (of course they replace them all anyway during an OH).

The inside of your hub looks so clean that you could eat off it. I am suspecting that the prior OH shop never greased it. You might want to consider sending your photos to the original OH shop.