RoundTwo Posted October 27 Report Posted October 27 The two main differences I have noticed after installing the Hartzell Scimitar on my J is a vibration at cruise and, the prop now stops in a vertical orientation instead is 1/7 or 2/8 like it did with the McCauley. The vibration isn’t noticeable at takeoff power, put as soon as power is pulled back it shows up as RPM is dialed back to 2,400. This could just be a function of resonance frequencies lining up at cruise RPM. The prop is oriented at 3/9 with #1 at TDC and it was dynamically balanced, to within 0.1 IPS, after several hours of flying to let the grease migrate to where it wanted to go. I have read articles discussing the non-standard orientation of 3/9 used on the 201 with the McCauley while most other installations orient 1/7. Any thoughts? I’m thinking I may look for a cheap BT accelerometer to use to see if I can get a better read on magnitude and frequency, just for a better dataset than the butt-o-meter. New Lord engine mounts were installed in 2023. Am I missing anything? Any suggestions of things to look for before taking it in?
Hank Posted October 27 Report Posted October 27 @Cody Stallings is our resident prop guru. He may have some advice for you.
RoundTwo Posted October 27 Author Report Posted October 27 10 minutes ago, Hank said: @Cody Stallings is our resident prop guru. He may have some advice for you. I bought the prop from Cody.
Hank Posted October 27 Report Posted October 27 Just now, RoundTwo said: I bought the prop from Cody. Have you discussed these questions with him? Do that before going somewhere to have it looked at. Other than that, I have nothing that I can contribute. My C has a 3-blade Hartzell prop, so far so good (18 years of ownership).
47U Posted October 27 Report Posted October 27 3 hours ago, RoundTwo said: he prop now stops in a vertical orientation instead is 1/7 or 2/8 like it did with the McCauley. Has the prop installation index been verified? 1
EricJ Posted October 27 Report Posted October 27 See Mooney Service Bulletin M20-206, on converting an IO-360-A1B6D to an -A3B6D. The only difference is how the prop is clocked on the crankshaft flange, and supposedly one way is smoother than the other. 2
RoundTwo Posted October 27 Author Report Posted October 27 On 10/27/2025 at 11:28 AM, Hank said: Have you discussed these questions with him? Do that before going somewhere to have it looked at. Other than that, I have nothing that I can contribute. My C has a 3-blade Hartzell prop, so far so good (18 years of ownership). Cody says it’s most likely an grease imbalance since the prop cavity has never been greased after being flown. I’ve now pumped it full and will hope for a smoother next flight. 1
RoundTwo Posted October 27 Author Report Posted October 27 22 minutes ago, 47U said: Has the prop installation index been verified? The proper index is 3 o’clock – 9 o’clock, and this has been verified. 1
RoundTwo Posted October 27 Author Report Posted October 27 2 hours ago, EricJ said: See Mooney Service Bulletin M20-206, on converting an IO-360-A1B6D to an -A3B6D. The only difference is how the prop is clocked on the crankshaft flange, and supposedly one way is smoother than the other. J model index is different than normal being a 3 o’clock – 9 o’clock index and I can confirm mine is clocked properly.
EricJ Posted October 27 Report Posted October 27 4 minutes ago, RoundTwo said: DJ model index is different than normal being a 3 o’clock – 9 o’clock index and I can confirm mine is clocked properly. It's either a -A1.. or a -A3. Those are the only two options. I've never been able to fully sort out exactly where either puts the prop, though.
PT20J Posted October 27 Report Posted October 27 55 minutes ago, EricJ said: It's either a -A1.. or a -A3. Those are the only two options. I've never been able to fully sort out exactly where either puts the prop, though. 3 puts TDC at about 4 o’clock on the low blade viewed from the rear with a two bladed prop 1
RoundTwo Posted October 27 Author Report Posted October 27 3 hours ago, EricJ said: It's either a -A1.. or a -A3. Those are the only two options. I've never been able to fully sort out exactly where either puts the prop, though. With my engine at #1 TDC, my prop is horizontal, not offset one way or the other.
Shadrach Posted October 28 Report Posted October 28 7 hours ago, RoundTwo said: Cody says it’s most likely pay Greece imbalance since the prop cavity has never been greased after being flown. I’ve now pumped it full and will hope for a smoother next flight. Did Cody tell you to do that? 2
PT20J Posted October 28 Report Posted October 28 The Hartzell prop hub is not supposed to be filled with grease. Hartzell has specific recommendations for greasing but if the hub is over greased the only way to rectify the situation is to disassemble the prop and clean it out. https://hartzellprop.com/MANUALS/131-0000-A.pdf 2
Shadrach Posted October 28 Report Posted October 28 Just as an aside. Vibrations in the cockpit are not always directly related to propeller balance. I was recently dealing with a minor vibration in cruise and a pronounced vibration any time the prop was driving the engine. This was due to some movement in the position of my exhaust pipe and it's hanger. The pipe had migrated ever so slightly in the ball joint causing the hanger to just kiss the firewall. This caused an almost undetectable harmonic in cruise, but at low power with the prop driving the engine, the mounts compressed just enough to increase the contact between the hanger and firewall. It was very noticeable and I had to fully inspect everything ahead of the firewall to catch it. Such a small thing but it had a huge effect on N, V, & H. Make sure that everything firewall forward is tidy and secure with no rubbing or interference. 4
OR75 Posted October 29 Report Posted October 29 (edited) give it some time for the counterweights to re-seat Edited October 29 by OR75
RoundTwo Posted October 29 Author Report Posted October 29 On 10/27/2025 at 9:23 PM, Shadrach said: Did Cody tell you to do that? Yes
RoundTwo Posted October 29 Author Report Posted October 29 On 10/27/2025 at 11:18 PM, PT20J said: The Hartzell prop hub is not supposed to be filled with grease. Hartzell has specific recommendations for greasing but if the hub is over greased the only way to rectify the situation is to disassemble the prop and clean it out. https://hartzellprop.com/MANUALS/131-0000-A.pdf According to the manual supplied with the prop, normal maintenance is to inject up to 30ml of grease, or until grease comes out of the vent hole. Based on the advice provided by Cody, the hub was SLOWLY filled with grease until the excess came out the vent holes. 1
RoundTwo Posted October 29 Author Report Posted October 29 9 hours ago, OR75 said: give it some time for the counterweights to re-seat I’ve got about 50 hours on it since being installed, still buzzing.
RoundTwo Posted October 29 Author Report Posted October 29 16 hours ago, Shadrach said: Just as an aside. Vibrations in the cockpit are not always directly related to propeller balance. I was recently dealing with a minor vibration in cruise and a pronounced vibration any time the prop was driving the engine. This was due to some movement in the position of my exhaust pipe and it's hanger. The pipe had migrated ever so slightly in the ball joint causing the hanger to just kiss the firewall. This caused an almost undetectable harmonic in cruise, but at low power with the prop driving the engine, the mounts compressed just enough to increase the contact between the hanger and firewall. It was very noticeable and I had to fully inspect everything ahead of the firewall to catch it. Such a small thing but it had a huge effect on N, V, & H. Make sure that everything firewall forward is tidy and secure with no rubbing or interference. It would be nice to be able to fly around without the cowl to ensure it isn’t hitting somewhere. 1
Shadrach Posted October 29 Report Posted October 29 18 hours ago, RoundTwo said: According to the manual supplied with the prop, normal maintenance is to inject up to 30ml of grease, or until grease comes out of the vent hole. Based on the advice provided by Cody, the hub was SLOWLY filled with grease until the excess came out the vent holes. From your manual: CAUTION 3: DO NOT ATTEMPT TO PUMP MORE THAN 1 FL. OZ. (30 ML) OF GREASE INTO THE LUBRICATION FITTING. USING MORE THAN 1 FL. OZ. (30 ML) OF GREASE COULD RESULT IN OVER SERVICING OF THE PROPELLER. VERIFY THE OUTPUT OF THE GREASE GUN BEFORE SERVICING THE PROPELLER. CAUTION 4: OVER LUBRICATING AN ALUMINUM HUB PROPELLER MAY CAUSE THE GREASE TO ENTER THE HUB CAVITY, LEADING TO EXCESSIVE VIBRATION AND/OR SLUGGISH OPERATION. THE PROPELLER MUST THEN BE DISASSEMBLED TO REMOVE THIS GREASE. (8) Pump a maximum of 1 fl. oz. (30 ml) grease into the lubrication fitting, or until grease emerges from the hole where the lubrication fitting or hole plug was removed - whichever occurs first. What you've posted and what the manual says are not quite the same. Based on your comments, I don't think that you understand that there is no seal on the hub side of the blade bearing race. I have seen multiple prop issues on multiple airplanes from overservicing. Hopefully, you did not really "fill it up" as that will cause the blade seals to herniate when the piston is actuated. If you think that you can "even out" the grease by pumping both sides until it pushes out the other zerk hole, you are mistaken. Grease pushed into the prop bearing race can migrate out of the race on the hub side before getting to the rear zerk fitting hole. This is why they limit servicing to 1 fl. oz. I hope it works out for you! The Georgia weather may have helped you dodge a bullet as the grease is less viscous at higher temps, so it may have pushed out the back before overfilling... 2 2
1980Mooney Posted October 29 Report Posted October 29 6 hours ago, RoundTwo said: According to the manual supplied with the prop, normal maintenance is to inject up to 30ml of grease, or until grease comes out of the vent hole. Based on the advice provided by Cody, the hub was SLOWLY filled with grease until the excess came out the vent holes. What grease are you using on this new Hartzell Scimitar?
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